Bsc nursing 1st year Nutrition unit-3(LIPID)

 UNIT  III

LIPIDS.         AK media

SHORT ESSAY.   

1. DESCRIBE LIPIDS UNDER THE FOLLOWING HEADINGS, CLASSIFICATION, FUNCTION   AND FOOD SOURCES OF FATS.

Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells. Examples of lipids include fats, oils, waxes, certain vitamins (such as A, D, E and K), hormones and most of the cell membrane that is not made up of protein

Classification

1.Very low-density lipoproteins (VLDL), 

2.Hhigh-density lipoproteins (HDL).

Fatty acids (saturated and unsaturated)

Glycerides (glycerol-containing lipids)

Nonglyceride lipids (sphingolipids, steroids, waxes)

Complex lipids (lipoproteins, glycolipids)


The Functions of Fats in the Body

Storing Energy. ...

Insulating and Protecting. ...

Regulating and Signaling. ...

Aiding Absorption and Increasing Bioavailability. ...

Contributing to the Smell, Taste, and Satiety of Foods. ...

Providing Essential Fatty Acids. ...

Attributions: 


Saturated fat  primary sources include:

Red meat (beef, lamb, pork)

Chicken skin.

Whole-fat dairy products (milk, cream, cheese)

Butter.

Ice cream.

Lard.

Tropical oils such as coconut and palm oil.






2.Define lipids and explain the classification of lipids.

Definition

Lipids are molecules that contain hydrocarbons and make up the building blocks of the structure and function of living cells. Examples of lipids include fats, oils, waxes

Classification of Lipids

Lipids can be classified into two main classes:

Nonsaponifiable lipids

Saponifiable lipids


Nonsaponifiable Lipids

A nonsaponifiable lipid cannot be disintegrated into smaller molecules through hydrolysis. Nonsaponifiable lipids include cholesterol, prostaglandins, etc


Saponifiable Lipids

A saponifiable lipid comprises one or more ester groups, enabling it to undergo hydrolysis in the presence of a base, acid, or enzymes, including waxes, triglycerides, sphingolipids and phospholipids.

Further, these categories can be divided into non-polar and polar lipids.

Nonpolar lipids, namely triglycerides, are utilized as fuel and to store energy.


3.  Explain in detail the functions of lipids.

Role of lipids in the body

Lipids have several roles in the body, these include acting as chemical messengers, storage and provision of energy and so forth.

Chemical messengers

All multicellular organisms use chemical messengers to send information between organelles and to other cells. torage and provision of energy Storage lipids are triacylglycerols. These are inert and made up of three fatty acids and a glycerol.

Maintenance of temperature

Layers of subcutaneous fat under the skin also help in insulation and protection from cold. Maintenance of body temperature is mainly done by brown fat as opposed to white fat

Membrane lipid layer formation

Membrane lipids are made of polyunsaturated fatty acids. Polyunsaturated fatty acids are important as constituents of the phospholipids, where they appear to confer several important properties to the membranes. One of the most important properties are fluidity and flexibility of the membrane.

Cholesterol formation

Much of the cholesterol is located in cell membranes. It also occurs in blood in free form as plasma lipoproteins. 

Prostaglandin formation and role in inflammation

The essential fatty acids, linoleic and linolenic acids are precursors of many different types of eicosanoids, including the hydroxyeicosatetraenes, prostanoids (prostaglandins, thromboxanes and prostacyclins), leukotrienes (and lipoxins) and resolvins etc. these play an important role in pain, fever, inflammation and blood clotting.

4. What are the sources of lipids? What is the calorific value and daily requirement of  lipids?

Mono unsaturated fat. This type of fat is found in plant oils. Common sources are nuts (almonds, cashews, pecans, peanuts, and walnuts) and nut products, avocados, extra virgin olive oil, sesame oil, high oleic safflower oil, sunflower oil, and canola oil.

Polyunsaturated fat. This type of fat is found mainly in plant-based foods, oils, and fish. Common sources are nuts (walnuts, hazel nuts, pecans, almonds, and peanuts), soybean oil, corn oil, safflower oil, flaxseed oil, canola oil, and fish (trout, herring, and salmon).

Saturated fat. This fat is found in animal products, dairy products, palm and coconut oils, and cocoa butter. Limit these products to less than 10 percent of your overall dietary fat consumption.

Trans  fatty acids

. Stick margarines, fast foods, commercial baked goods, and some snack foods contain trans fats. Limit your consumption of these products to keep trans fats to less than 1 percent of your fat consumption.

Omega-3 fatty acids(linolenic acid). Good sources of these are canola oil, flaxseed oil, soybean oil, olive oil, nuts, seeds, whole grains, legumes, and green leafy vegetables.

DHA and EPA. Good sources of these are cod liver oil and fish such as tuna, herring, mackerel, salmon, and trout.

Omega-6 fatty acids (linoleic acid). Eggs, poultry, most vegetable oils, wheat germ oil, whole grains, baked goods, and cereals contain these 

fatty acids

    Calorific value and daily requirement of  lipids

Lipids are a concentrated source of energy and provide almost twice the amount of energy than that supplied by proteins and carbohydrates. Children aged between 4-18 years require ~6500 to 14000 kJ per day.

5. Explain in detail digestion and absorption of fats.

The process of fat digestion involves a series of steps that begin the moment food enters your mouth. Heres a look at the process from beginning to end:

DIGESTION

Mouth

The digestion process begins when you start chewing your food. Your teeth break the food into smaller pieces, and your saliva moistens the food so that its easier for it to move through your esophagus and into your stomach. Your saliva also contains enzymes that begin breaking down the fat in your food.

Esophagus

When you swallow, a series of muscle contractions called peristalsis moves the food through your esophagus and into your stomach.

Stomach

Your stomach lining produces acids and enzymes that break down your food further so that the foods can pass to the small intestine.

Small intestine

The majority of fat digestion happens once it reaches the small intestine. This is also where the majority of nutrients are absorbed. Your pancreas produces enzymes that break down fats, carbohydrates, and proteins

ABSORPTION

After the fat has been digested, fatty acids are passed through the lymph system and then throughout the body via your bloodstream to be used or stored for energy, cell repair, and growth. Your lymph system also absorbs fatty acids to help fight infection. Adipose, which is fat tissue, takes triglyceride from the chylomicrons. Each chylomicron gets smaller, eventually leaving a remnant thats rich in cholesterol and taken in by the liver.

6.. Write note on excessive intake and deficiency of fats.

Dietary fat deficiency is rare in healthy people who eat a balanced, nutritious diet. However, some conditions can put you at risk for fat deficiency, such as:

eating disorders

large bowel resection (colectomy)

inflammatory bowel disease

cystic fibrosis

pancreatic insufficiency

an extremely low fat diet

excessive intake of fats causes

Cardiovascular disease. 

Heart attack. Ischemic stroke. 

Congestive heart failure. 

Arrhythmia. 

Heart valve problems. 

Obesity.

III.SHORT ANSWERS

1)What is calorific values of Lipids?

The calorific values of lipids and carbohydrates respectively, are 9.3 k cals/g and 4.5 k cals/g. 

2) What are Refined Oils?

Definition: An oil has been refined by using chemicals that are harmful to us. In short it means to 'purify'. 

AVOID

Canola oil

Vegetable oil

Soybean

Safflower

Corn oils

Margarine (or any other buttery spread)

3)What is Emulsification?

Emulsification is the formation of emulsions from two immiscible liquid phases is probably the most versatile property of surface-active agents for practical applications and, as a result, has been extensively studied.

4)What are the effects of over consumption of Lipids?

Cardiovascular disease. 

Heart attack. Ischemic stroke. 

Congestive heart failure. 

Arrhythmia. 

Heart valve problems. 

Obesity.


5)What is the deficiency of lipids called as?

Wolman's disease, also known as acid lipase deficiency, is a severe lipid storage disorder that is usually fatal by age 1.

What are the differences between essential and non essential fatty acids?

The body is capable of synthesizing most of the fatty acids it needs from food. These fatty acids are known as nonessential fatty acids. However, there are some fatty acids that the body cannot synthesize and these are called essential fatty acids.

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