Bsc nursing 1st year Nutrition unit-6 Vitamin
UNIT VI
VITAMINS
I.LONG ESSAYS ESSAYS
1)DEFINE VITAMINS, CLASSIFY VITAMINS; EXPLAIN THE DIETARY SOURCES DAILY REQUIREMENTS OF VITAMIN A
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second.
CLASSIFICATION OF VITAMINS
Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.[24] Because they are not as readily stored, more consistent intake is important. Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.
SOURCES
For the most part, vitamins are obtained from the diet, but some are acquired by other means: for example, microorganisms in the gut flora produce vitamin K and biotin; and one form of vitamin D is synthesized in skin cells when they are exposed to a certain wavelength of ultraviolet light present in sunlight. Humans can produce some vitamins from precursors they consume: for example, vitamin A is synthesized from beta carotene; and niacin is synthesized from the amino acid tryptophan.The Food Fortification Initiative lists countries which have mandatory fortification programs for vitamins folic acid, niacin, vitamin A and vitamins B1, B2 and B1
How much vitamin A do needed?
The amount of vitamin A you need depends on your age and sex. Average daily recommended amounts are listed below in micro grams (mc g) of retinol activity equivalents (RAE).
Life Stage
Recommended Amount
*Birth to 6 months
..400 mc g RAE
*Infants 712 months
..500 mc g RAE
*Children 13 years
..300 mc g RAE
*Children 48 years
..400 mc g RAE
*Children 913 years
..600 mc g RAE
*Teen boys 1418 years
..900 mc g RAE
*Teen girls 1418 years
..700 mc g RAE
*Adult men
..900 mc g RAE
*Adult women
..700 mc g RAE
*Pregnant teens
..750 mc g RAE
*Pregnant women
..770 mc g RAE
*Breastfeeding teens
..1,200 mc g RAE
*Breastfeeding women
..1,300 mc g RAE
2)DEFINE VITAMINS. CLASSIFY VITAMINS; EXPLAIN THE DIETARY SOURCES DAILY REQUIREMENTS, ABSORPTION, FUNCTIONS, DEFICIENCY OF VITAMIN D
..A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second.
Classification of vitamins
Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.] Because they are not as readily stored, more consistent intake is important.[25] Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.
Good sources of vitamin D
Oily fish such as salmon, sardines, herring and mackerel.
Red meat.
Lliver.
Egg yolks.
Fortified foods such as some fat spreads and breakfast cereals.
How much vitamin D do needed?
The amount of vitamin D you need each day depends on your age. Average daily recommended amounts are listed below in micrograms (mcg) and International Units (IU):
Life Stage
Recommended Amount
*Birth to 12 months
..10 m cg (400 IU)
*Children 113 years
..15 mc g (600 IU)
*Teens 1418 years
..15 mc g (600 IU)
*Adults 1970 years
..15 mc g (600 IU)
*Adults 71 years and older
..20 mc g (800 IU)
*Pregnant and breastfeeding teens and women
..15 mc g (600 IU)
# Functions of Vitamin D
Vitamin D is both a nutrient we eat and a hormone our bodies make. It is a fat-soluble vitamin that has long been known to help the body absorb and retain calcium and phosphorus; both are critical for building bone. Also, laboratory studies show that vitamin D can reduce cancer cell growth, help control infections and reduce inflammation. Many of the bodys organs and tissues have receptors for vitamin D, which suggest important roles beyond bone health, and scientists are actively investigating other possible functions.
# Defeciency of vitamin D
People who are obese tend to have lower blood vitamin D levels. Vitamin D accumulates in excess fat tissues but is not easily available for use by the body when needed. Higher doses of vitamin D supplementation may be needed to achieve a desirable blood level. Conversely, blood levels of vitamin D rise when obese people lose weight.
People who have undergone gastric bypass surgery, which typically removes the upper part of the small intestine where vitamin D is absorbed.
Conditions resulting from prolonged vitamin D deficiency:
Rickets: A condition in infants and children of soft bones and skeletal deformities caused by failure of bone tissue to harden.
Osteomalacia: A condition in adults of weak and softened bones that can be reversed with supplementation. This is different than osteoporosis, in which the bones are porous and brittle and the condition is irreversible.
Toxicity
Vitamin D toxicity most often occurs from taking supplements. The low amounts of the vitamin found in food are unlikely to reach a toxic level, and a high amount of sun exposure does not lead to toxicity because excess heat on the skin prevents D3 from forming. It is advised to not take daily vitamin D supplements containing more than 4,000 IU unless monitored under the supervision of your doctor.
3)DEFINE VITAMINS. MENTION FAT SOLUBLE VITAMIN. EXPLAIN VITAMIN K IN DETAIL.
# Definition of vitamins
A vitamin is an organic molecule that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet.
*Fat-soluble vitamins
Fat-soluble vitamins are stored in the body's cells and are not excreted as easily as water-soluble vitamins. They do not need to be consumed as often as water-soluble vitamins, although adequate amounts are needed. If you take too much of a fat-soluble vitamin, it could become toxic. Your body is especially sensitive to too much vitamin A from animal sources (retinol) and too much vitamin D. A balanced diet usually provides enough fat-soluble vitamins.
Fat-soluble vitamins
Nutrient.
Function
Sources.
Vitamin A (and its precursor*, beta-carotene)
*A precursor is converted by the body to the vitamin.
Needed for vision, healthy skin and mucous membranes, bone and tooth growth, immune system health
Vitamin A from animal sources (retinol): fortified milk, cheese, cream, butter, fortified margarine, eggs, liver
Beta-carotene (from plant sources): Leafy, dark green vegetables; dark orange fruits (apricots, cantaloupe) and vegetables (carrots, winter squash, sweet potatoes, pumpkin)
Vitamin D
Needed for proper absorption of calcium; stored in bones
Egg yolks, liver, fatty fish, fortified milk, fortified margarine. When exposed to sunlight, the skin can make vitamin D.
Vitamin E
Antioxidant; protects cell walls
Polyunsaturated plant oils (soybean, corn, cottonseed, safflower); leafy green vegetables; wheat germ; whole-grain products; liver; egg yolks; nuts and seeds
Vitamin K
Needed for proper blood clotting
Leafy green vegetables such as kale, collard greens, and spinach; green vegetables such as broccoli, brussels sprouts, and asparagus; also produced in intestinal tract by bacteria
Vitamin k
Vitamin K refers to a group of fat-soluble vitamins that play a role in blood clotting, bone metabolism, and regulating blood calcium levels.
The body needs vitamin K to produce prothrombin, a protein and clotting factor that is important in blood clotting and bone metabolism. People who use blood-thinning medications, such as warfarin, or Coumadin, should not start consuming additional vitamin K without first asking a doctor.
Deficiency is rare, but, in severe cases, it can increase trusted Source clotting time, leading to hemorrhage and excessive bleeding.
Vitamin K1, or phylloquinone, comes from plants. It is the main type Trusted Source of dietary vitamin K. A lesser source is vitamin K2, or menaquinone, which occurs in some animal-based and fermented foods.
USES
Phylloquinone, also known as vitamin K1, is found in plants. When people eat it, bacteria in the large intestine convert it to its storage form, vitamin K2. It is absorbed in the small intestine and stored in fatty tissue and the liver.
Without vitamin K, the body cannot produce prothrombin, a clotting factor that is necessary for blood clotting and bone metabolism.
Most Americans are not at riskTrusted Source of a vitamin-K deficiency. It is most likely to affect newborns and those with a malapsorption problem, due, for example, to short-bowel syndrome, cystic fibrosis, celiac disease, or ulcerative colitis.
Newborns normally receive a vitamin K injection to protect them from bleeding in the skull, which could be fatal.
The recommended adequate intake for vitamin K depends on age and gender. Women aged 19 years and over should consume 90 microgramsTrusted Source (mcg) a day, and men should have 120 mcg.
4)EXPLAIN THE DIETARY SOURCES, FUNCTIONS, DEFICIENCY MANIFESTATIONS AND DAILY REQUIREMENTS OF VITAMIN C.
Vitamin C, also known as ascorbic acid, has several important functions.
These include:
Helping to protect cells and keeping them healthy
Maintaining healthy skin, blood vessels, bones and cartilage
Helping with wound healing
Lack of vitamin C can lead to scurvy.
Good sources of vitamin C
Vitamin C is found in a wide variety of fruit and vegetables.
Good sources include:
Citrus fruit, such as oranges and orange juice
Strawberries
Blackcurrants
Broccoli
Brussels sprouts
Potatoes
* How common is vitamin C deficiency?
Scurvy due to vitamin C deficiency is rare in the UK.
There are certain groups of people who are more at risk of vitamin C deficiency. They include:
People dependent on drugs and/or alcohol who may not have a healthy, balanced diet.
People who go on very restrictive diets.
People living on a low income who tend not to buy foods with a high vitamin C content.
People with a medical condition that affects the body's ability to digest and absorb food, such as Crohn's disease and ulcerative colitis.
Older people who may eat a less varied diet.
Smokers. Smoking affects the absorption of vitamin C from foods and also vitamin C is used up in the body more quickly in those who smoke.
Pregnant and breastfeeding women because they need higher amounts of
vitamin C
* What are the symptoms of vitamin C?
* The first symptoms of vitamin C deficiency tend to be:
..Tiredness and weakness.
..Muscle and joint pains.
..Easy bruising.
..Spots that look like tiny, red-blue bruises on your skin.
Other symptoms can include:
..Dry skin.
..Splitting hair.
..Swelling and discoloration of your gums.
..Sudden and unexpected bleeding from your gums.
..Nosebleeds.
..Poor healing of wounds.
..Problems fighting infections.
..Bleeding into joints, causing severe joint pains.
..Changes in your bones.
..Tooth loss.
..Weight loss.
How much vitamin C do needed?
The amount of vitamin C you need each day depends on your age. Average daily recommended amounts for different ages are listed below in milligrams (mg).
Life Stage
Recommended Amount
*Birth to 6 months
..40 mg
*Infants 712 months
..50 mg
*Children 13 years
..15 mg
*Children 48 years
..25 mg
*Children 913 years
..45 mg
*Teens 1418 years (boys)
..75 mg
*Teens 1418 years (girls)
..65 mg
*Adults (men)
..90 mg
*Adults (women)
..75 mg
*Pregnant teens
..80 mg
*Pregnant women
..85 mg
*Breastfeeding teens
..115 mg
*Breastfeeding women
..120 mg
If you smoke, add 35 mg to the above values to calculate your total daily recommended amount.
5)DESCRIBE THE DIETARY SOURCES, DEFICIENCY MANIFESTATIONS AND DAILY REQUIREMENTS OF THIAMINE.
SOURCES of Thiamine (Vitamin B1)
Food
Food sources of Thiamine include whole grains, meat, and fish. Breads, cereals, and infant formulas in the United States and many other countries are fortified with thiamin.The most common sources of thiamine in the U.S. diet are cereals and bread. Pork is another major source of the vitamin. Dairy products and most fruits contain little Thiamine. About half of the thiamine in the U.S. diet comes from foods that naturally contain Thiamine; the remainder comes from foods to which Thiamine has been added.
Heating foods containing Thiamine can reduce their Thiamine content. For example, bread has 20%30% less Thiamine than its raw ingredients, and Pasteurization reduces Thiamine content (which is very small to begin with) in milk by up to 20% . Because Thiamine dissolves in water, a significant amount of the vitamin is lost when cooking water is thrown out. Processing also alters Thiamine levels in foods; for example, unless white rice is enriched with Thiamine, it has one tenth the amount of Thiamine in unenriched brown rice
#Recommended Intakes
Intake recommendations for Thiamine and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies (formerly National Academy of Sciences). DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:
Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
Table 1 lists the current RDAs for Thiamine. For infants from birth to 12 months, the FNB established an AI for Thiamine that is equivalent to the mean intake of Thiamine in healthy, breastfed infants.
Table 1: Recommended Dietary Allowances (RDAs) for Thiamine
*Age
*Male
*Female
*Pregnancy
*Lactation
Birth to 6 months*
.. 0.2 mg
.. 0.2 mg
712 months*
0.3 mg
0.3 mg
*13 years
0.5 mg
0.5 mg
*48 years
0.6 mg
0.6 mg
*913 years
0.9 mg
0.9 mg
*1418 years
1.2 mg
1.0 mg
1.4 mg
1.4 mg
*19-50 years
1.2 mg
1.1 mg
1.4 mg
1.4 mg
*51+ years
1.2 mg
1.1 mg
6)DESCRIBE THE DIETARY SOURCES, DEFICIENCY MANIFESTATIONS AND DAILY REQUIREMENTS OF RIBOFLAVIN.
Riboflavin also called vitamin B2 is important for the growth, development, and function of the cells in your body. It also helps turn the food you eat into the energy you need.
How much riboflavin do I need?
The amount of riboflavin you need depends on your age and sex. Average daily recommended amounts are listed below in milligrams (mg).
Life Stage
Recommended Amount
*Birth to 6 months
0.3 mg
*Infants 712 months
0.4 mg
*Children 13 years
0.5 mg
*Children 48 years
0.6 mg
*Children 913 years
0.9 mg
*Teen boys 1418 years
1.3 mg
*Teen girls 1418 years
1.0 mg
*Men
1.3 mg
*Women
1.1 mg
*Pregnant teens and women
1.4 mg
*Breastfeeding teens and women
1.6 mg
#What foods provide riboflavin?
Riboflavin is found naturally in some foods and is added to many fortified foods. You can get recommended amounts of riboflavin by eating a variety of foods, including the following:
Eggs, organ meats (such as kidneys and liver), lean meats, and low-fat milk
Green vegetables (such as asparagus, broccoli, and spinach)
Fortified cereals, bread, and grain products
#What kinds of riboflavin dietary supplements are available?
Riboflavin is found in multivitamin/multimineral supplements, in B-complex dietary supplements, and in supplements containing only riboflavin. Some supplements have much more than the recommended amounts of riboflavin, but your body cant absorb more than about 27 mg at a time.
Am I getting enough riboflavin?
Most people in the United States get enough riboflavin from the foods they eat and deficiencies are very rare. However, certain groups of people are more likely than others to have trouble getting enough riboflavin:
Athletes who are vegetarians (especially strict vegetarians who avoid dairy foods and eggs)
Pregnant women and breastfeeding women and their babies
People who are vegan
People who do not eat dairy foods
People with a genetic disorder called riboflavin transporter deficiency. This disorder prevents the body from properly absorbing and using riboflavin, causing riboflavin deficiency
7)WHAT ARE THE SOURCES AND FUNCTIONS OF VITAMIN K?
Sources of vitamin K
Several foods are rich in vitamin K-1, and vitamin K-2 is much less common. Bacteria in the gut can convert some K-1 into K-2.
Fermented foods are a good source of vitamin K-2.
Also, because it is fat-soluble, organ meats and high-fat dairy products contain fairly substantial quantities of vitamin K-2. Conversely, lean meats, such as poultry, are not good sources of K-2.
Dietary sources of vitamin K-1 include:
*Dark leafy green vegetables, such as spinach, kale, and collards
*Lettuce
*Turnips
*Broccoli
*Carrots
*Vegetable oils
*Blueberries
*Grapes
# Dietary sources of vitamin K-2 include:
*Natto, a traditional Japanese dish of fermented soybeans
*Sauerkraut
*Dairy products, especially hard cheeses
*Liver and other organ meats
*Beef
*Pork
*Egg yolks
*Chicken
*Fatty fish, such as salmon
Functions
*The body needs both types of vitamin K to produce prothrombin, a protein that plays crucial roles in blood clotting, bone metabolism, and heart health. Vitamin K also helps facilitate energy production in the mitochondria of cells.
*Vitamin K-1 is primarily involved in blood coagulation. K-2 may have a more diverse range of functions in the body.
*In a long-term study involving 36,629 participants, researchers observed an association
*between high intakes of vitamin K-2 and a reduced risk of developing peripheral arterial disease (PAD), particularly in people with high blood pressure. However, the authors concluded that K-1 had no effect on PAD risk.
*Vitamin K has antioxidant properties. It protects cellular membranes from damage due to excess free radicals, in a process known as peroxidation. Blood thinning medication, such as warfarin, can lower the antioxidative potential of vitamin K.
8)WHAT ARE WATER SOLUBLE VITAMINS? WRITE A NOTE ON FUNCTIONS AND DEFICIENCY OF THIAMINE.
Water soluble vitamins
Thiamine
Thiamine functions in the body in the form of Thiamine pyrophosphate (TPP), the coenzyme for the transfer of active aldehyde in carbohydrate metabolism and decarboxylation of α-keto acids such as pyruvate. The requirement for thiamine is directly correlated with carbohydrate intake and increases as the metabolic rate increases due to pregnancy, lactation, or increased physical exercise. The 1980 RDA of 0.5 mg/1,000 kcal was set to maintain normal levels of TPP-dependent erythrocyte transketolase activity and urinary excretion. For those whose total caloric intake is less than 2,000 kcal, at least 1.0 mg/day is recommended.
Riboflavin
In its coenzyme forms (flavin mononucleotide and flavin adenine dinucleotide), riboflavin functions in oxidation-reduction reactions in energy production, in the respiratory chain, and in many other metabolic pathways. Richest food sources of riboflavin include liver, milk, dark-green leafy vegetables, and enriched breads and cereals.
Niacin
In nutrition literature, the term niacin is used generically to encompass the active forms of this vitamin, nicotinic acid and nicotinamide; however, estimates of niacin requirements take into account preformed niacin as well as that obtained as equivalent (NE) in the body from tryptophan metabolism. For this purpose, it is estimated that when 60 mg of tryptophan are consumed by an adult, enough is oxidized to produce 1 mg of niacin (NRC, 1980).
Vitamin B6
Vitamin B6 is the generic term used for pyridoxine, pyridoxal, and pyridoxamine, the coenzyme forms of which are pyridoxal phosphate and pyridoxamine phosphate. Vitamin B6-dependent enzymes are needed in a wide range of reactions, most of which involve amino acid metabolism. The 1980 RDAs were based on a ratio of 0.02 mg of vitamin B6 per gram of protein consumed. The allowance for adult females was therefore set at 2.0 mg/day, assuming a protein intake of 100 g/day; for adult males, it was set at 2.2 mg/day, assuming a protein intake of 110 g/day. A lower allowance presumably would be appropriate for those with lower protein intakes.
Vitamin B12
Vitamin B12 substances are physiologically active cobalamins. The coenzyme (5'-deoxyadenosyl) and methyl forms of this vitamin are essential for the recyling of the active folate coenzyme, for the methylation of homocysteine to form methionine, and for metabolism of propionate. Vitamin B12 is also essential in the metabolism of fatty acids and aliphatic amino acids through its role in the isomerization of methylmalonyl-CoA to succinyl-CoA.
Folacin (Folic Acid or Folate)
Folacin intakes have been studied very little, because values for this vitamin in food composition tables are imputed. In addition, present analytical methods for this vitamin are not very reliable. There is also some concern that the 1980 RDA for folacin is unrealistically high (DHHS-USDA, 1986).
THIAMINE DEFICIENCY
Thiamin deficiency (causing beriberi) is most common among people subsisting on white rice or highly refined carbohydrates in developing countries and among alcoholics. Symptoms include diffuse polyneuropathy, high-output heart failure, and Wernicke-Korsakoff syndrome. Thiamin is given to help diagnose and treat the deficiency.
Early symptoms of thiamin deficiency are nonspecific: fatigue, irritability, poor memory, sleep disturbances, precordial pain, anorexia, and abdominal discomfort.
Different forms of beriberi cause different symptoms.
✓Dry beriberi refers to peripheral neurologic deficits due to thiamin deficiency. These deficits are bilateral and roughly symmetric, occurring in a stocking-glove distribution. They affect predominantly the lower extremities, beginning with paresthesias in the toes, burning in the feet (particularly severe at night), muscle cramps in the calves, pains in the legs, and plantar dysesthesias. Calf muscle tenderness, difficulty rising from a squatting position, and decreased vibratory sensation in the toes are early signs. Muscle wasting occurs. Continued deficiency worsens polyneuropathy, which can eventually affect the arms.
✓Wernicke-Korsakoff syndrome, which combines Wernicke encephalopathy and Korsakoff psychosis, occurs in some alcoholics who do not consume foods fortified with thiamine. Wernicke encephalopathy consists of psychomotor slowing or apathy, nystagmus, ataxia, ophthalmoplegia, impaired consciousness, and, if untreated, coma and death. It probably results from severe acute deficiency superimposed on chronic deficiency. Korsakoff psychosis consists of mental confusion, dysphonia, and confabulation with impaired memory of recent events. It probably results from chronic deficiency and may develop after repeated episodes of Wernicke encephalopathy.
✓Cardiovascular (wet) beriberi is myocardial disease due to thiamin deficiency. The first effects are vasodilation, tachycardia, a wide pulse pressure, sweating, warm skin, and lactic acidosis. Later, heart failure develops, causing orthopnea and pulmonary and peripheral edema. Vasodilation can continue, sometimes resulting in shock.
✓Infantile beriberi occurs in infants (usually by age 3 to 4 weeks) who are breastfed by thiamin-deficient mothers. Heart failure (which may occur suddenly), aphonia, and absent deep tendon reflexes are characteristic.
✓Because thiamine is necessary for glucose metabolism, glucose infusions may precipitate or worsen symptoms of deficiency in thiamine-deficient people.
9)WHAT ARE FAT SOLUBLE VITAMINS? WRITE A NOTE ON VITAMIN A.
Vitamins can be classified based on their solubility.
Most are water-soluble, meaning they dissolve in water. In contrast, the fat-soluble vitamins are similar to oil and do not dissolve in water.
Fat-soluble vitamins are most abundant in high-fat foods and are much better absorbed into your bloodstream when you eat them with fat.
There are four fat-soluble vitamins in the human diet:
*Vitamin A
*Vitamin D
*Vitamin E
*Vitamin K
This article provides a comprehensive overview of the fat-soluble vitamins, their health benefits, functions and main dietary sources.
Role and Function of Vitamin A
Vitamin A supports many critical aspects of body function, including:
*Vision maintenance: Vitamin A is essential for maintaining the light-sensing cells in the eyes and for the formation of tear fluid (2Trusted Source).
*Immune function: Vitamin A deficiency impairs immune function, increasing susceptibility to infections (3Trusted Source, 4Trusted Source).
*Body growth: Vitamin A is necessary for cell growth. Deficiency may slow or prevent growth in children (5Trusted Source).
*Hair growth: It is also vital for hair growth. Deficiency leads to alopecia, or hair loss (6Trusted Source).
*Reproductive function: Vitamin A maintains fertility and is vital for fetal development
Dietary Sources
*Vitamin A is only found in animal-sourced foods. The main natural food sources are liver, fish liver oil and butter.
Recommended Intake
*The table below shows the recommended daily allowance (RDA) for vitamin A. The RDA is the estimated amount of vitamin A that the vast majority (about 97.5%) of people need to meet their daily requirements.
*This table also shows the tolerable upper intake limit (UL), which is the highest level of daily intake considered safe for 97.5% of healthy people (11Trusted Source)
RDA (IU / mcg)
UL (IU / mcg)
Infants
06 months
1,333 / 400
2,000 / 600
712 months
1,667 / 500
2,000 / 600
Children
13 years
1,000 / 300
2,000 / 600
48 years
1,333 / 400
3,000 / 900
913 years
2,000 / 600
5,667 / 1700
Women
1418 years
2,333 / 700
9,333 / 2800
1970 years
2,333 / 700
10,000 / 3000
Men
1418 years
3,000 / 900
9,333 / 2800
1970 years
3,000 / 900
10,000 / 3000
✓Vitamin A Deficiency
*Dry eyes: Severe deficiency may cause xerophthalmia, a condition characterized by dry eyes caused by reduced tear fluid formation (2Trusted Source).
*Blindness: Serious vitamin A deficiency may lead to total blindness. In fact, it is among the most common preventable causes of blindness in the world (14Trusted Source).
*Hair loss: If you are vitamin A deficient, you may start to lose your hair (15Trusted Source).
*Skin problems: Deficiency leads to a skin condition known as hyperkeratosis or goose flesh (16Trusted Source).
*Poor immune function: Poor vitamin A status or deficiency makes people prone to infections (3Trusted Source).
SHORT ESSAYS
1)Explain functions of Vitamin A.
*Helping your body's natural defence against illness and infection (the immune system) work properly
*Helping vision in dim light
*Keeping skin and the lining of some parts of the body, such as the nose, healthy
*Vitamin A helps form and maintain healthy teeth, skeletal and soft tissue, mucus membranes, and skin. It is also known as retinol because it produces the pigments in the retina of the eye.
*Vitamin A promotes good eyesight, especially in low light. It also has a role in healthy pregnancy and breastfeeding.
Vitamin A plays a role in a variety of functions throughout the body, such as:
✓Vision.
✓Gene transcription.
✓Immune function.
✓Embryonic development and reproduction.
✓Bone metabolism.
✓Haematopoiesis.
✓Skin and cellular health.
✓Teeth.
2)Explain deficiency and hypervitaminosis of Vitamin A
*Hypervitaminosis A, or vitamin A toxicity, occurs when you have too much vitamin A in your body. This condition may be acute or chronic. Acute toxicity occurs after consuming large amounts of vitamin A over a short period of time, typically within a few hours or days.
*Chronic toxicity occurs when large amounts of vitamin A build up in your body over a long period of time. Symptoms include changes to vision, bone pain, and skin changes.
*Chronic toxicity can lead to liver damage and increased pressure on your brain. Hypervitaminosis A can be diagnosed using blood tests to check your vitamin A levels. Most people improve simply by decreasing their intake of vitamin A.
✓Excess amounts of vitamin A are stored in your liver, and it accumulates over time. Most people develop vitamin A toxicity by taking high-dose dietary supplements, possibly due to mega vitamin therapy.
✓A mega vitamin therapy involves consuming very large doses of certain vitamins in an attempt to prevent or treat diseases.
✓It may also be caused by long-term use of certain acne treatments that contain high doses of vitamin A, such as isotretinoin (Sotret, Absorica).
✓Acute vitamin A toxicity is usually the result of accidental ingestion when it occurs in children.
3)Explain functions of Vitamin D
*Vitamin D which acts both as a nutrient and a hormone is a quintessential element highly significant for a host of bodily functions thanks to its wide range of therapeutic efficacies.
*Calcium, being the building block of bones is absorbed by the body due to the presence of Vitamin D which is extremely beneficial in the natural growth and remodelling of bones. It reduces the risk of fracture, strengthen the bones, maintain overall body balance and provides the body with a strong and perfect skeletal structure.
*Researches also show the importance of vitamin D in getting strong muscles. A by-product of Vitamin D helps in the contraction and relaxation of muscles. Thus, providing strength and supporting the skeletal frame of the body.
*Vitamin D is also essential for the dental health. It prevents tooth decay and loss, strengthen the gums and reduces risk of any oral infection.
*Vitamin D, being a fat-soluble vitamin plays a vital role in regulating the renal functions and protecting the kidney from any infections. It plays a major role in cellular growth, repair and metabolism. A sensible exposure to sunlight is very effective in wound healing and repair.
*Vitamin D also plays a key role in reducing obesity and maintaining proper weight. The abundance of vitamin D in the body restores the function of the appetite hormone leptin, which gives you a feeling of fullness and reduces the tendency of snacking all the time, thus aiding in weight loss.
4)Mention deficiency and hypervitaminosis of Vitamin D
✓A number of regions have published guidelines defining vitamin deficiencies and advising specific intakes for healthy people, with different recommendations for women, men, infants, the elderly, and during pregnancy and breast feeding including Japan, the European Union, the United States, and Canada. These documents have been updated as research is published. In the US, Recommended Dietary Allowances (RDAs) were first set in 1941 by the Food and Nutrition Board of the National Academy of Sciences. There were periodic updates, culminating in the Dietary Reference Intakes.Updated in 2016, the US Food and Drug Administration published a set of tables that define Estimated Average Requirements (EARs) and (RDAs). RDAs are higher to cover people with higher than average needs. Together, these are part of Dietary Reference Intakes. For a few vitamins, there is not sufficient information to set EARs and RDAs. For these, an Adequate Intake is shown, based on an assumption that what healthy people consume is sufficient. Countries do not always agree on the amounts of vitamins needed to safeguard against deficiency. For example, for vitamin C, the RDAs for women for Japan, the European Union (called Population Reference Intakes) and the US are 100, 95 and 75 mg/day, respectively. India sets its recommendation at 40 mg/day
# Vitamin deficiency is the condition of a long-term lack of a vitamin. When caused by not enough vitamin intake it is classified as a primary deficiency, whereas when due to an underlying disorder such as malabsorption it is called a secondary deficiency. An underlying disorder may be metabolic as in a genetic defect for converting tryptophan to niacin or from lifestyle choices that increase vitamin needs, such as smoking or drinking alcohol. Governments guidelines on vitamin deficiencies advise certain intakes for healthy people, with specific values for women, men, babies, the elderly, and during pregnancy or breastfeeding. Many countries have mandated vitamin food fortification programs to prevent commonly occurring vitamin deficiencies.
# Conversely hypervitaminosis refers to symptoms caused by vitamin intakes in excess of needs, especially for fat-soluble vitamins that can accumulate in body tissues.
# The history of the discovery of vitamin deficiencies progressed over centuries from observations that certain conditions for example, scurvy could be prevented or treated with certain foods having high content of a necessary vitamin, to the identification and description of specific molecules essential for life and health. During the 20th century, several scientists were awarded the Nobel Prize in Physiology or Medicine or the Nobel Prize in Chemistry for their roles in the discovery of vitamins.
5)Write a short essay on Vitamin E
✓Vitamin E is a group of eight fat soluble compounds that include four tocopherols and four tocotrienols. Vitamin E deficiency, which is rare and usually due to an underlying problem with digesting dietary fat rather than from a diet low in vitamin E, can cause nerve problems. Both the tocopherols and tocotrienols occur in α (alpha), β (beta), γ (gamma) and δ (delta) forms, as determined by the number and position of methyl groups on the chromanol ring. All eight of these vitamers feature a chromane double ring, with a hydroxyl group that can donate a hydrogen atom to reduce free radicals, and a hydrophobic side chain which allows for penetration into biological membranes.
✓Vitamin E may have various roles as a vitamin. Many biological functions have been postulated, including a role as a fat-soluble antioxidant. In this role, vitamin E acts as a radical scavenger, delivering a hydrogen (H) atom to free radicals. As it is fat-soluble, vitamin E is incorporated into cell membranes, which are therefore protected from oxidative damage.
✓Vitamin E affects gene expression and is an enzyme activity regulator, such as for protein kinase C (PKC) which plays a role in smooth muscle growth with vitamin E participating in deactivation of PKC to inhibit smooth muscle growth.
Deficiency
*Vitamin E deficiency is rare in humans, occurring as a consequence of abnormalities in dietary fat absorption or metabolism rather than from a diet low in vitamin E. One example of a genetic abnormality in metabolism is mutations of genes coding for alpha-tocopherol transfer protein (α-TTP). Humans with this genetic defect exhibit a progressive neurodegenerative disorder known as ataxia with vitamin E deficiency (AVED) despite consuming normal amounts of vitamin E. Large amounts of alpha-tocopherol as a dietary supplement are needed to compensate for the lack of α-TTP. Vitamin E deficiency due to either malabsorption or metabolic anomaly can cause nerve problems due to poor conduction of electrical impulses along nerves due to changes in nerve membrane structure and function. In addition to ataxia, vitamin E deficiency can cause peripheral neuropathy, myopathies, retinopathy and impairment of immune responses.
6.Write a short essay on Vitamin K
Vitamin K refers to a group of fat-soluble vitamins that play a role in blood clotting, bone metabolism, and regulating blood calcium levels.The body needs vitamin K to produce prothrombin, a protein and clotting factor that is important in blood clotting and bone metabolism. People who use blood-thinning medications, such as warfarin, or Coumadin, should not start consuming additional vitamin K without first asking a doctor. Deficiency is rare, but, in severe cases, it can increase clotting time, leading to hemorrhage and excessive bleeding.Vitamin K1, or phylloquinone, comes from plants. It is the main type of dietary vitamin K. A lesser source is vitamin K2, or menaquinone, which occurs in some animal-based and fermented foods.
USES
* Phylloquinone, also known as vitamin K1, is found in plants. When people eat it, bacteria in the large intestine convert it to its storage form, vitamin K2. It is absorbed in the small intestine and stored in fatty tissue and the liver.
* Without vitamin K, the body cannot produce prothrombin, a clotting factor that is necessary for blood clotting and bone metabolism.
* Most Americans are not at risk of a vitamin-K deficiency. It is most likely to affect newborns and those with a malapsorption problem, due, for example, to short-bowel syndrome, cystic fibrosis, celiac disease, or ulcerative colitis.
* Newborns normally receive a vitamin K injection to protect them from bleeding in the skull, which could be fatal.
* The recommended adequate intake for vitamin K depends on age and gender. Women aged 19 years and over should consume 90 micrograms (mcg) a day, and men should have 120 mcg.
SOURCES
*10 sprigs of parsley contains 90 micrograms (mcg)
*A 3-ounce serving of natto contains 850 mcg
*A half-cup serving of frozen and boiled collard greens contains 530 mcg
*One cup of raw spinach contains 145 mcg
*1 tablespoon of soybean oil contains 25 mcg
*A half-cup serving of grapes contains 11 mcg
*A hard-boiled egg contains 4 mcg
7.Define Vitamins. Classify vitamins
Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Water-soluble vitamins dissolve easily in water and, in general, are readily excreted from the body, to the degree that urinary output is a strong predictor of vitamin consumption.Because they are not as readily stored, more consistent intake is important.Fat-soluble vitamins are absorbed through the intestinal tract with the help of lipids (fats). Vitamins A and D can accumulate in the body, which can result in dangerous hypervitaminosis. Fat-soluble vitamin deficiency due to malabsorption is of particular significance in cystic fibrosis.
A vitamin is an organic molecule (or a set of molecules closely related chemically, i.e. vitamers) that is an essential micronutrient which an organism needs in small quantities for the proper functioning of its metabolism. Essential nutrients cannot be synthesized in the organism, either at all or not in sufficient quantities, and therefore must be obtained through the diet. Vitamin C can be synthesized by some species but not by others; it is not a vitamin in the first instance but is in the second. The term vitamin does not include the three other groups of essential nutrients: minerals, essential fatty acids, and essential amino acids. Most vitamins are not single molecules, but groups of related molecules called vitamers. For example, there are eight vitamers of vitamin E: four tocopherols and four tocotrienols. Some sources list fourteen vitamins, by including choline,[3] but major health organizations list thirteen: vitamin A (as all-trans-retinol, all-trans-retinyl-esters, as well as all-trans-beta-carotene and other provitamin A carotenoids), vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B7 (biotin), vitamin B9 (folic acid or folate), vitamin B12 (cobalamins), vitamin C (ascorbic acid), vitamin D (calciferols), vitamin E (tocopherols and tocotrienols),and vitamin K (phylloquinone and menaquinones).[4][5][6]
8)What are fat soluble vitamins
The fat-soluble vitamins, A, D, E, and K, are stored in the body for long periods of time and generally pose a greater risk for toxicity than water-soluble vitamins when consumed in excess. Eating a normal, well-balanced diet will not lead to toxicity in otherwise healthy individuals. However, taking vitamin supplements that contain megadoses of vitamins A, D, E and K may lead to toxicity.
Vitamin A
Vitamin A, also called retinol, has many functions in the body. In addition to helping the eyes adjust to light changes, vitamin A plays an important role in bone growth, tooth development, reproduction, cell division, gene expression, and regulation of the immune system.
Vitamin D
Vitamin D plays a critical role in the bodys use of calcium and phosphorous. It works by increasing the amount of calcium absorbed from the small intestine, helping to form and maintain bones. Vitamin D benefits the body by playing a role in immunity and controlling cell growth and may protect against osteoporosis, high blood pressure, cancer, and other diseases.
Vitamin E
Vitamin E benefits the body by acting as an antioxidant, and protecting vitamins A and C, red blood cells, and essential fatty acids from destruction. Research from decades ago suggested that taking antioxidant supplements, vitamin E in particular, might help prevent heart disease and cancer. However, newer findings indicate that people who take antioxidant and vitamin E supplements are not better protected against heart disease and cancer than non-supplement users. Many studies show a link between regularly eating an antioxidant rich diet full of fruits and vegetables, and a lower risk for heart disease, cancer, Alzheimers Disease, and several other diseases.
Vitamin k
Vitamin K is naturally produced by the bacteria in the intestines, and plays an essential role in normal blood clotting, promoting bone health, and helping to produce proteins for blood, bones, and kidneys.
Food Sources for Vitamin K
Good food sources of vitamin K are green, leafy-vegetables such as turnip greens, spinach, cauliflower, cabbage and broccoli, and certain vegetables oils including soybean oil, cottonseed oil, canola oil and olive oil. Animal foods, in general, contain limited amounts of vitamin K.
9.What is the role of Vitamin A in vision?
*Vitamin A plays a crucial role in vision by maintaining a clear cornea, which is the outside covering of your eye.
*This vitamin is also a component of rhodopsin, a protein in your eyes that allows you to see in low light conditions. Vitamin A deficiency is rare in developed countries, but if unaddressed can lead to a serious condition called xerophthalmia.
*Xerophthalmia is a progressive eye disease which begins with night blindness.
*If vitamin A deficiency continues, your tear ducts and eyes can dry out. Eventually, your cornea softens, resulting in irreversible blindness Vitamin A may also help protect against other eye afflictions. Some studies suggest that diets high in vitamin A may be associated with a reduced risk of cataracts and age-related macular degeneration (AMD).For general eye health, vitamin-A-rich foods are recommended over supplements.
*Sweet potatoes are an excellent source, as are leafy green vegetables, pumpkins and bell peppers
10.What are functions of Vitamin C
Functions
✓A natural antioxidant, vitamin C plays a key role in scavenging free radicals from the body and thereby takes part in reducing damage from inflammation and oxidation and hence is a key component for fighting a multitude of pathological conditions and infections.
✓Vitamin C is an absolute requirement when it comes to wound healing and collagen synthesis. Vitamin C and its supplements have marked effect on reducing the risks of cancer, cardiac and respiratory diseases. Vitamin C rich foods also play a key role in the production of collagen, a protein found in bones, tissues and blood vessels.
✓Historical studies suggest the vitamin C is extremely effective in preventing and treating scurvy a disease caused due to lack of vitamin C. It is also extremely beneficial for treating tuberculosis, HIV infection, gum disease, bronchitis, asthma, liver damage, inflammation of the urinary bladder and prostate gland, infertility, restless leg syndrome, metal poisoning, gout, tetanus infection, nerve pain and swine flu.
✓Several studies also suggest the usefulness of vitamin C in treating Alzheimers disease, dementia, depression, autism, attention deficit-hyperactivity disorder (ADHD), schizophrenia, chronic fatigue syndrome, psychoses and Parkinsons disease.
✓Additionally, scientific researches have concluded the significance of vitamin C in promoting cardiovascular health. It is used for lowering high blood pressure, high cholesterol, preventing blood coagulation in the veins and arteries, preventing hardening of arteries and normalising the irregular heartbeat. Regular intake of vitamin C also reduces the risk of heart attack and strokes.
✓Vitamin C is also found beneficial in healing burn wounds, treating cataract, glaucoma, age-related macular degeneration, vision defects, constipation, gastritis, stomach ulcer, dysentery, Lymes disease, arthritis, back pain, joint inflammation, osteoporosis, heatstroke, hay fever and dental problem.
11.List the deficiencies of Vitamin C
°Rough, Bumpy Skin. ...
°Corkscrew-Shaped Body Hair. ...
°Bright Red Hair Follicles. ...
°Spoon-Shaped Fingernails With Red Spots or Lines. ...
°Dry, Damaged Skin. ...
°Easy Bruising. ...
°Slowly Healing Wounds. .. Painful, Swollen Joints.
°Weak Bones
°Bleeding Gums and Tooth Loss
°Poor Immunity
°Persistent Iron Deficiency Anemia
°Fatigue and Poor Mood
°Unexplained Weight Gain
°Chronic Inflammation and Oxidative Stress
12.Mention the B complex Vitamins and sources
Consuming adequate amounts of the eight B complex vitamins puts you on the path to a healthy diet. Some top sources of B vitamins include meat (especially liver), seafood, poultry, eggs, dairy products, legumes, leafy greens, seeds and fortified foods, such as breakfast cereal and nutritional yeast.
Vitamin B complex is composed of eight B vitamins:
°B-1 (thiamine)
°B-2 (riboflavin)
°B-3 (niacin)
°B-5 (pantothenic acid)
°B-6 (pyridoxine)
°B-7 (biotin)
°B-9 (folic acid)
°B-12 (cobalamin)
SOURCES
*Milk.
*Cheese.
*Eggs.
*Liver and kidney.
*Meat, such as chicken and red meat.
*Fish, such as tuna, mackerel, and salmon.
*Shellfish, such as oysters and clams.
*Dark green vegetables, such as spinach and kale.
*Vegetables, such as beets, avocados, and potatoes
*Whole grains and cereals
*Beans, such as kidney beans, black beans, and chickpeas
*Nuts and seeds
*Fruits, such as citrus, banana, and watermelon
*Soy products, such as soy milk and tempeh
*Blackstrap molasses
*Wheat germ
*Yeast and nutritional yeast
13.Mention deficiency disorders of B complex vitamins
Most people get enough B vitamins by eating a balanced diet. However, its still possible to be deficient.
The following symptoms may be a sign that youre not getting enough B vitamins:
✓skin rashes
✓cracks around the mouth
✓scaly skin on the lips
✓swollen tongue
✓fatigue
✓weakness
✓anemia
✓confusion
✓irritability or depression
✓nausea
✓abdominal cramps
✓diarrhea
✓constipation
✓numbness or tingling in the feet and hands
If you're experiencing any of these symptoms and aren't sure why, make an appointment to see your doctor.
Although its possible that you're experiencing a vitamin B deficiency, these symptoms also overlap with many other underlying conditions. Your doctor can make a diagnosis and advise you on any next steps.
Can being deficient increase your risk of certain conditions?
If you're deficient in B vitamins you may experience a range of symptoms depending on which B vitamins you're lacking.
If left untreated, deficiency could increase your risk of developing:
✓Anemia
✓Digestive issues
✓Skin conditions
✓Infections
✓peripheral neuropathy
Vitamin B-12 deficiency, in particular, may increase your risk of neuropsychiatric disorders.Researchers are also investigating its role in hyperhomocysteinemia and atherosclerosis.
Babies born to women who were deficient in folic acid during pregnancy are more likely to have birth defects.
14.Mention sources, requirements and deficiency of vitamin C
Good sources of vitamin C
°Citrus fruit, such as oranges and orange juice.
°Peppers.
°Strawberries.
°Blackcurrants.
°Broccoli.
°Brussels sprouts.
°Potatoes.
Requirements
°Age. Male. Female
9-13 year. 45mg. 45mg
14-18 year. 75mg. 65mg
19+year. 90mg. 75mg
Smokers
Individuals who smoke require 35 mg/day more vitamin C than nonsmokers.
Defeciencies
°Rough, Bumpy Skin. ...
°Corkscrew-Shaped Body Hair. ...
°Bright Red Hair Follicles. ...
°Spoon-Shaped Fingernails With Red Spots or Lines. ...
°Dry, Damaged Skin. ...
°Easy Bruising. ...
°Slowly Healing Wounds. ...
°Painful, Swollen Joints.
°Weak Bones
15.What is vitamin K. Sources, uses and requirements
Vitamin K refers to a group of fat-soluble vitamins that play a role in blood clotting, bone metabolism, and regulating blood calcium levels.The body needs vitamin K to produce prothrombin, a protein and clotting factor that is important in blood clotting and bone metabolism
Uses
Phylloquinone, also known as vitamin K1, is found in plants. When people eat it, bacteria in the large intestine convert it to its storage form, vitamin K2. It is absorbed in the small intestine and stored in fatty tissue and the liver.
Without vitamin K, the body cannot produce prothrombin, a clotting factor that is necessary for blood clotting and bone metabolism.
Most Americans are not at riskTrusted Source of a vitamin-K deficiency. It is most likely to affect newborns and those with a malapsorption problem, due, for example, to short-bowel syndrome, cystic fibrosis, celiac disease, or ulcerative colitis.
Newborns normally receive a vitamin K injection to protect them from bleeding in the skull, which could be fatal.
The recommended adequate intake for vitamin K depends on age and gender. Women aged 19 years and over should consume 90 microgramsTrusted Source (mcg) a day, and men should have 120 mcg.
Recommendations
Life Stage. | Recommended Amount
Adult men 19 years and older.| 120 mc g
Adult women 19 years and older|90mcg
Pregnant or breastfeeding teens|75mcg
Pregnant or breastfeeding |90mcg
women
16.Explain vitamin A. deficiency & effects.
Vitamin A deficiency can result from inadequate intake, fat malabsorption, or liver disorders. Deficiency impairs immunity and hematopoiesis and causes rashes and typical ocular effects (eg, xerophthalmia, night blindness).
Primary vitamin A deficiency is usually caused by
°Prolonged dietary deprivation
It is endemic in areas such as southern and eastern Asia, where rice, devoid of beta-carotene, is the staple food. Xerophthalmia due to primary deficiency is a common cause of blindness among young children in developing countries.
Secondary vitamin A deficiency may be due to
°Decreased bioavailability of provitamin A carotenoids
°Interference with absorption, storage, or transport of vitamin A
Interference with absorption or storage is likely in celiac disease, cystic fibrosis, pancreatic insufficiency, duodenal bypass, chronic diarrhea, bile duct obstruction, giardiasis, and cirrhosis. Vitamin A deficiency is common in prolonged protein-energy undernutrition not only because the diet is deficient but also because vitamin A storage and transport is defective.
Signs and symptoms of vitamin A deficiency
✓Impaired dark adaptation of the eyes, which can lead to night blindness, is an early symptom of vitamin A deficiency.
✓Xerophthalmia (which is nearly pathognomonic) results from keratinization of the eyes. It involves drying (xerosis) and thickening of the conjunctivae and corneas.
✓Superficial foamy patches composed of epithelial debris and secretions on the exposed bulbar conjunctiva (Bitot spots) develop. In advanced deficiency, the cornea becomes hazy and can develop erosions, which can lead to its destruction (keratomalacia).
✓Keratinization of the skin and of the mucous membranes in the respiratory, gastrointestinal, and urinary tracts can occur. Drying, scaling, and follicular thickening of the skin and respiratory infections can result.
Immunity is generally impaired.
The younger the patient, the more severe are the effects of vitamin A deficiency. Growth retardation and infections are common among children. Mortality rate can exceed 50% in children with severe vitamin A deficiency.
17.Mention Sources, requirements, deficiency disorders of thiamine
Sources
Sources of Thiamine
Food
Food sources of thiamine include whole grains, meat, and fish. Breads, cereals, and infant formulas in the United States and many other countries are fortified with thiamine .The most common sources of thiamine in the U.S. diet are cereals and bread. Pork is another major source of the vitamin. Dairy products and most fruits contain little thiamine. About half of the thiamine in the U.S. diet comes from foods that naturally contain thiamine; the remainder comes from foods to which thiamine has been added.
Heating foods containing thiamine can reduce their thiamine content. For example, bread has 20%30% less thiamine than its raw ingredients, and pasteurization reduces thiamine content (which is very small to begin with) in milk by up to 20%. Because thiamine dissolves in water, a significant amount of the vitamin is lost when cooking water is thrown out . Processing also alters thiamine levels in foods; for example, unless white rice is enriched with thiamine, it has one tenth the amount of thiamine in unenriched brown rice
Requirements
°Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
°Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
°Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
°Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
Thiamine Deficiency
✓In addition to insufficient intakes of thiamine from the diet, the causes of thiamine deficiency include lower absorption or higher excretion rates than normal due, for example, to certain conditions (such as alcohol dependence or HIV/AIDS) or use of some medications.
✓In its early stage, thiamine deficiency can cause weight loss and anorexia, confusion, short-term memory loss, and other mental signs and symptoms; muscle weakness; and cardiovascular symptoms (such as an enlarged heart).
✓The most common effect of thiamine deficiency is beriberi, which is characterized mainly by peripheral neuropathy and wasting. People with this condition have impaired sensory, motor, and reflex functions. In rare cases, beriberi causes congestive heart failure that leads to edema in the lower limbs and, occasionally, death
✓A more common manifestation of thiamine deficiency in the United States is Wernicke-Korsakoff syndrome . This disorder is about 810 times more common in people with chronic alcoholism than in the general population, but it can also develop in patients who have severe gastrointestinal disorders, rapidly progressing hematologic malignancies, drug use disorders, or AIDS.
18.Mention sources, requirements, deficiency disorders of Riboflavin
Recommendations
Intake recommendations for riboflavin and other nutrients are provided in the Dietary Reference Intakes (DRIs) developed by the Food and Nutrition Board (FNB) at the Institute of Medicine of the National Academies . DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy people. These values, which vary by age and sex, include:
°Recommended Dietary Allowance (RDA): Average daily level of intake sufficient to meet the nutrient requirements of nearly all (97%98%) healthy individuals; often used to plan nutritionally adequate diets for individuals.
°Adequate Intake (AI): Intake at this level is assumed to ensure nutritional adequacy; established when evidence is insufficient to develop an RDA.
°Estimated Average Requirement (EAR): Average daily level of intake estimated to meet the requirements of 50% of healthy individuals; usually used to assess the nutrient intakes of groups of people and to plan nutritionally adequate diets for them; can also be used to assess the nutrient intakes of individuals.
°Tolerable Upper Intake Level (UL): Maximum daily intake unlikely to cause adverse health effects.
Sources of Riboflavin
Food
Foods that are particularly rich in riboflavin include eggs, organ meats (kidneys and liver), lean meats, and milk. Green vegetables also contain riboflavin. Grains and cereals are fortified with riboflavin in the United States and many other countries .The largest dietary contributors of total riboflavin intake in U.S. men and women are milk and milk drinks, bread and bread products, mixed foods whose main ingredient is meat, ready-to-eat cereals, and mixed foods whose main ingredient is grain. The riboflavin in most foods is in the form of FAD, although the main form in eggs and milk is free riboflavin .
About 95% of riboflavin in the form of FAD or FMN from food is bioavailable up to a maximum of about 27 mg of riboflavin per meal or dose.The bioavailability of free riboflavin is similar to that of FAD and FMN . Because riboflavin is soluble in water, about twice as much riboflavin content is lost in cooking water when foods are boiled as when they are prepared in other ways, such as by steaming or microwaving
Riboflavin Deficiency
Riboflavin deficiency is extremely rare in the United States. In addition to inadequate intake, causes of riboflavin deficiency can include endocrine abnormalities (such as thyroid hormone insufficiency) and some diseases.The signs and symptoms of riboflavin deficiency (also known as ariboflavinosis) include skin disorders, hyperemia (excess blood) and edema of the mouth and throat, angular stomatitis (lesions at the corners of the mouth), cheilosis (swollen, cracked lips), hair loss, reproductive problems, sore throat, itchy and red eyes, and degeneration of the liver and nervous system. People with riboflavin deficiency typically have deficiencies of other nutrients, so some of these signs and symptoms might reflect these other deficiencies. Severe riboflavin deficiency can impair the metabolism of other nutrients, especially other B vitamins, through diminished levels of flavin coenzymes Anemia and cataracts can develop if riboflavin deficiency is severe and prolonged
19.Mention sources, requirements, deficiency disorders of Vitamin B3
*Liver. Liver is one of the best natural sources of niacin. ...
°Chicken Breast. Chicken, especially the breast meat, is a good source of both niacin and lean protein. ...
°Tuna. ...
°Turkey. ...
°Salmon. ...
°Anchovies. ...
°Pork. ...
°Ground Beef.
*Chicken breast: 59% of
the RDI
*Light tuna, canned in oil: 53% of
the RDI
*Beef: 33% of the RDI
*Smoked salmon: 32% of
the RDI
*Peanuts: 19% of the RDI
*Lentils: 10% of the RDI
REQUIREMENTS
Infants
06 months: 2 mg/day*
712 months: 4 mg/day*
*These figures represent the Adequate Intake (AI), which is similar to RDI but based on weaker scientific evidence.
Children
13 years: 6 mg/day
48 years: 8 mg/day
913 years: 12 mg/day
Adolescents and adults
Men 14 years and older: 16 mg/day
Women 14 years and older: 14 mg/day
Pregnant women: 18 mg/day
Breastfeeding women: 17 mg/day
According to the Office of Dietary Supplements (ODS)Trusted Source, a person who lacks vitamin B-3 may experience:
°A pigmented rash on skin that is exposed to the sun
°Rough appearance to the skin
°Bright red tongue
°Fatigue or apathy
°Vomiting, constipation, and diarrhea
°Circulatory problems
°Depression
°Headache
°Memory loss
^In severe cases, hallucinations
A severe lack of vitamin B-3 can result in pellagra. The condition can be fatal.
Factors that can lead to low levels of B-3 include:
°Having a diet low in tryptophans or a condition that reduces the bodys ability to convert tryptophan to niacin, such as Hartnup disease or carcinoid syndrome
°undernutrition, for example, due to alcohol use disorder, anorexia, and inflammatory bowel disease
°A low intake of vitamin B-2, B-6, or iron, as this can reduce the amount of tryptophan that converts to niacin
20.Mention sources, requirements, deficiency disorders of Vitamin B9
Sources
Foods that contain high amounts of folate include:
°Leafy, green vegetables, such as broccoli and spinach.
°Brussels sprouts.
°Peas.
°Citrus.
°Fruits, such as bananas and melons.
°Tomato juice.
°Eggs.
°Beans.
REQUIREMNTS
RDA: The Recommended Dietary Allowance for folate is listed as micro grams (mcg) of dietary folate equivalents (DFE). Men and women ages 19 years and older should aim for 400mcg DFE. Pregnant and lactating women require 600mcg DFE and 500mcg DFE, respectively.
The symptoms of folate deficiency are often subtle. They include:
°fatigue
°gray hair
°mouth sores
°tongue swelling
°growth problems
The symptoms of anemia that occur due to folate deficiency include:
°persistent fatigue
°Weakness
°Lethargy
°Pale skin
°Shortness of breath
°Irritability
°Chronic disease
°Celiac disease
°Certain types of cancers
°Severe kidney problems that require dialysis
21.Mention sources, requirements, deficiency disorders of Vitamin B12
Sources
What foods provide vitamin B12?
Vitamin B12 is found naturally in a wide variety of animal foods and is added to some fortified foods. Plant foods have no vitamin B12 unless they are fortified. You can get recommended amounts of vitamin B12 by eating a variety of foods including the following:
*Beef liver and clams, which are the best sources of vitamin B12.
*Fish, meat, poultry, eggs, milk, and other dairy products, which also contain vitamin B12.
*Some breakfast cereals, nutritional yeasts and other food products that are fortified with vitamin B12. To find out if vitamin B12 has been added to a food product, check the product labels.
Requirements
The amount of vitamin B12 you need each day depends on your age. Average daily recommended amounts for different ages are listed below in micro grams (mcg):
Life Stage. Recommended
Amount
Birth to 6 months. 0.4mcg
Infants 7-12 months. 0.5mcg
Children 1-3 years. 0.9mcg
Children 4-8 years. 1.2mcg
Children 9-13 years. 1.8mcg
Teens 14-18 years. 2.4mcg
Adults. 2.4mcg
Pregnant teens and women. 2.6 mcg
Breastfeeding teens and . 2.8 mcg
women
Deficiency symptoms
Vitamin B-12 deficiency occurs when the body does not receive enough vitamin B-12.
It can result in irreversible and potentially severe damage, especially to the nervous system and brain.
Even slightly lower-than-normal levels of vitamin B-12 can trigger deficiency symptoms, such as depression, confusion, memory problems, and fatigue. However, these symptoms alone are not specific enough to diagnose vitamin B-12 deficiency.
Other symptoms of vitamin B-12 deficiency include constipation, loss of appetite, and weight loss.
Once symptoms escalate, they can include neurological changes, such as numbness and tingling in the hands and feet. Some people may have difficulty maintaining balance.
Infants who lack vitamin B-12 may demonstrate unusual movements, such as face tremors, as well as reflex problems, feeding difficulties, irritation, and eventual growth problems if the deficiency is left untreated.
Vitamin B-12 deficiency carries a serious risk of permanent nerve and brain damage. Some people with insufficient vitamin B-12 have a higher risk of developing psychosis, mania, and dementia.
Insufficient vitamin B-12 can also lead to anemia. The most common symptoms of anemia are fatigue, shortness of breath, and an irregular heartbeat. People with anemia might also experience:
A sore mouth or tongue
Weight loss
Pale or yellowing skin
Diarrhea
Menstrual problems
III.SHORT ANSWERS
1)DEFINE PRO-VITAMINS.
A provitamin is a substance that may be converted within the body to a vitamin. The term previtamin is a synonym. The term "provitamin" is used when it is desirable to label a substance with little or no vitamin activity, but which can be converted to an active form by normal metabolic processes.
2)WHAT ARE CAROTENE
The term carotene (also carotin, from the Latin carota, "carrot" is used for many related unsaturated hydrocarbon substances having the formula C40Hx, The two primary isomers of carotene, α-carotene and β-carotene, differ in the position of a double bond (and thus a hydrogen) in the cyclic group at one end (the right end in the diagram at right). β-Carotene is the more common form and can be found in yellow, orange, and green leafy fruits and vegetables. As a rule of thumb, the greater the intensity of the orange colour of the fruit or vegetable, the more β-carotene it contains. Carotene protects plant cells against the destructive effects of ultraviolet light. β-Carotene is an antioxidant.
3)DEFINE NIGHT BLINDNESS.
Night blindness (nyctalopia) is the inability to see well at night or in poor light such as in a restaurant or movie theater. It is often associated with an inability to quickly adapt from a well-illuminated to a poorly illuminated environment.
4)DEFINE EXOPHTHALMIA
Xerophthalmia is a progressive eye disease caused by vitamin A deficiency. Lack of vitamin A can dry out your tear ducts and eyes. Xerophthalmia can develop into night blindness or more serious damage to your cornea, the outer layer of your eye.
5)WHAT IS THE CAUSE OF RICKETS
The most common cause of rickets is a lack of vitamin D or calcium in a child's diet. Both are essential for children to develop strong and healthy bones. Sources of vitamin D are: sunlight your skin produces vitamin D when it's exposed to the sun, and we get most of our vitamin D this way.
6(MENTION THE CAUSE OF OSTEOMALACIA
Vitamin D deficiency is the most common cause of osteomalacia worldwide. Certain surgeries. Normally, the stomach breaks down food to release calcium and other minerals that are absorbed in the intestine.
7)VITAMIN E HAS SELENIUM SPARING ACTION. GIVE REASON.
The importance of maintaining adequate levels of Se, vitamin C and vitamin E is underscored by studies indicating that low antioxidant status may be associated with increased risk of developing various diseases. Se has been shown to spare both AA and AT.
8)WHAT IS CAUSED BY TONICITY OF VITAMIN A
The tonicity of a solution is related to its effect on the volume of a cell. Solutions that do not change the volume of a cell are said to be isotonic. A hypotonic solution causes a cell to swell, whereas a hypertonic solution causes a cell to shrink.
9)WHAT IS SOURCES OF VITAMIN D
Salmon. Salmon is a popular fatty fish and great source of vitamin D.
Herring and sardines. Herring is a fish eaten around the world.
Cod liver oil. Cod liver oil is a popular supplement.
Canned tuna. Many people enjoy canned tuna because of its flavor and easy storage methods. ...
Egg yolks. ...
Mushrooms. ..
10)DEFINE BERI BERI
A disease in which the body doesn't have enough vitamin B1 (thiamin). Beriberi is usually caused by poor diet or alcoholism. Symptoms include loss of appetite, weakness, pain in the limbs, shortness of breath and swollen feet or legs.
11)WHAT IS CHEILOSIS
Cheilosis is a condition where the corners of the mouth become inflamed, which can lead to cracking and pain at the corners of the mouth. The cracks can split and bleed; they can also make it difficult to yawn, chew, or talk. It can happen to people of any age group. It is also called cheilitis, angular cheilitis, angular cheilosis, and perleche.
12)DEFINE PELLAGRA
A deficiency disease caused by a lack of nicotinic acid or its precursor tryptophan in the diet. It is characterized by dermatitis, diarrhoea, and mental disturbance, and is often linked to over-dependence on maize as a staple food.
13(DEFINE PERNICIOUS ANEMIA
Pernicious anemia is defined as a type of vitamin B12 deficiency that results from impaired uptake of vitamin B-12 due to the lack of a substance known as intrinsic factor (IF) produced by the stomach lining.
Pernicious anemia is a condition caused by too little vitamin B12 in the body. It is one form of vitamin B12 deficiency anemia.
14)WHAT IS VITAMIN B12
Vitamin B₁₂, also known as cobalamin, is a water-soluble vitamin involved in the metabolism of every cell of the human body. It is one of eight B vitamins. It is a cofactor in DNA synthesis, and in both fatty acid and amino acid metabolism.
15(DEFINE MEGALOBLASTIC ANEMIA
Megaloblastic anemia is a condition in which the bone marrow produces unusually large, structurally abnormal, immature red blood cells (megaloblasts). Bone marrow, the soft spongy material found inside certain bones, produces the main blood cells of the body -red cells, white cells, and platelets.
16)DEFINE SCURVY
A disease caused by a deficiency of vitamin C, characterized by swollen bleeding gums and the opening of previously healed wounds, which particularly affected poorly nourished sailors until the end of the 18th century.
17)DEFINE WERNICKES ENCEPHALOPATHY
Wernicke encephalopathy (WE) is an acute neurological condition characterized by a clinical triad of ophthalmoparesis with nystagmus, ataxia, and confusion. This is a life-
threatening illness caused by thiamine deficiency, which primarily affects the peripheral and central nervous systems.
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