Explain the classification, sources, function, requirements and deficiencies of fats.

Fats are basically subgroup of lipids and are known as triglycerides. These oily substances are  found beneath the skin and surrounding the organs are the primary energy depots of animals. They are highly complex compounds composed of carbon, hydrogen & oxygen. They are present in nearly all the foods that we eat, adding a special taste and flavor to the food.

Classification:

A fat molecule consists of two kinds of parts: a glycerol backbone and three fatty acid tails. Fatty acids can be classified in various ways as follows:

Based on the degree of saturation : 

1. Saturated fatty acids – have no double or triple bonds between the carbon atoms. Oils and fats with saturated fatty acids are solid at room temperature e.g. Ghee, butter, palm kernel oil, coconut oil

sources:

It is mostly in animal foods, such as milk, cheese, and meat. Poultry and fish have less saturated fat than red meat. Saturated fat is also in tropical oils, such as coconut oil, palm oil, and cocoa butter. You'll find tropical oils in many snacks and in nondairy foods, such as coffee creamers and whipped toppings. Foods made with butter, margarine, or shortening (cakes, cookies, and other desserts) have a lot of saturated fat. Saturated fat can raise your cholesterol. 

2. Unsaturated fatty acids – have one or more double bonds between the carbon atoms.

i.  Monounsaturated fatty acids (MUFA) – have a single double bond in between the carbon atoms e.g. Oleic Acid present in palmolein, groundnut oil, olive oil, sesame oil, cottonseed oil, red palm oil, mustard oil etc.

ii. Polyunsaturated fatty acids (PUFA) – have two or more double bonds between the carbon atoms. Sunflower oil, corn oil & safflower oil are rich sources of PUFA.

• Omega-3 fatty acids are found in foods from plants like soybean oil, canola oil, walnuts, and flaxseed. They are also found in fatty fish and shellfish as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Salmon, anchovies, herring, sardines, Pacific oysters, trout, Atlantic mackerel, and Pacific mackerel are high in EPA and DHA and lower in mercury. A healthy diet includes 8 ounces or more of these types of fish a week, averaging 250 mg a day of these omega-3 fatty acids.footnote2
• Omega-6 fatty acids are found mostly in liquid vegetable oils like soybean oil, corn oil, and safflower oil.

3. Trans fatty acid - An unhealthy isomer, made during the process of hydrogenation of oils. Vanaspati is an example of hydrogenated fat. The naturally occurring isomer of unsaturated fatty acids is the cis form.

Sources: 

• Processed foods.
• Snack foods, such as chips and crackers.
• Cookies.
• Some margarine and salad dressings.
• Foods made with shortening and partially hydrogenated oils

Based on Nutritional properties: 

Essential fatty acids – are the ones which are very important for growth & development but cannot be synthesized by the body. Linoleic (omega 6) and linolenic acid (omega 3) are the two essential fatty acids. Thus, they must be supplied by the diet. Rich food sources of essential fatty acids are- soyabean, safflower, sunflower,cotton seed oil, and other cooking oils, oily fish like cod, salmon, cereals and legumes, nuts, etc.

Non – essential fatty acids – are the ones which can be synthesised in the body & are not required from the diet. Stearic, palmitic & oleic acids are the non-essential fatty acids.

· Fats in our diet can also be classified on the basis of their visibility as:

Invisible fats – fats which are a part of foods and hence not visible to the eye for instance. the fat

present in fish, milk & milk products, meat, egg, nuts & oilseeds.

Visible fats – are the added to food during preparation & processing. These are fats

that can be seen. e.g. oils, ghee, butter, vanaspati & cream

Function:

1.Dietary fat has a very important role to play in our bodies. Fats are the chief source of energy

for the body. Excess fat is stored inside the body (in the abdomen, surrounding the organs &

laced throughout the muscle tissue) as a reserve of energy to be used in times of need.

2.Fats are concentrated sources of energy. One gram fat provides 9kcal; twice the amount as

compared to carbohydrates & proteins. Adding some fat to food increases its energy density,

thereby reducing the bulk of the diet. This is especially important for small children who

cannot have a large quantity of food at a meal. Example adding some ghee to the dal or

kheer served to the small child, willmake it energy dense.

3.Fat is an integral part of the structure of the human body; all body cells contain fat in their cell

membranes. Amongst healthy & non-obese men & women; 15-25% of the total body weight

is fat.

4.Essential fatty acids and long chain PUFA synthesized from these like EPA, DHA and

Arachidonic acid perform vital functions in the body. They lead to formation of other

substances in the body which are needed for the regulation of a number of vital functions

like blood pressure, blood clotting, immune responses, inflammatory responses and

regulation of body temperature, etc. DHA is important for normal development &

maturation of the retina of the eye & brain development during the first 1000 days.

5.The stored fat acts like an insulator preventing the body from losing heat easily, thus helping

to regulate body temperature.

6.Adipose tissue provides a protective cushioning/ padding around the delicate internal organs

of the body such as liver, heart & kidneys.

7.It keeps the gastrointestinal tract lubricated helping in smooth movement of food.

8.Fat provide higher satiety value to the meals as it reduces gastric motility, meaning that the

movement of the ingested food out of the stomach slows down thereby giving a feeling of

fullness for a longer time.

9.Dietary Fat is required for the absorption of fat soluble vitamins – A, D, E and K. A zero fat

diet is considered unhealthy.

10. Fat provides variety & flavour to the food thereby increasing the palatability of the food.

Health Significance of Fats:

- Consuming the right combination of fats & oils in appropriate quantities is important. Ideally

calories from fat should be between 20-30% of the total calories, with less than 10% calories

coming from saturated fats. Eating too little fat can result in poor absorption of fat soluble

vitamins (Vitamins A, D, E & K) as well as overdependence on carbohydrates to provide the

energy resulting in a very bulky diet. Unsaturated fatty acids like PUFA and MUFA help to

decrease the risk of heart diseases by lowering total cholesterol and LDL (Bad) cholesterol

levels. Omega 3 fatty acids prevent inflammation and accumulation of fatty material in blood

vessels thus protecting against heart diseases. They also prevent thrombosis or clotting of blood

thus reducing the risk of strokes.

.On the other hand, excessive intake of fat can lead to weight gain & obesity. There is increased

risk of cardiovascular diseases and certain types of cancers. Excessive consumption of saturated

fatsraises the total and LDL cholesterol levels. They have also been shown to contribute to

insulin resistance. Hence, they increase the risk of heart disease and diabetes. Trans fats also

increase the risk of heart disease by increasing LDL cholesterol, decreasing HDL (Good)

cholesterol, increasing inflammation and insulin resistance in the body.

Enumerate the role of water in maintenance of electrolyte balance.

Role of Dietary Fiber in Human Health

Explain the classification, source, function, requirements and deficiencies of Riboflavin, Thiamine, Niacin and Folic acid.

Explain the classification, sources, functions, requirements and deficiency of fats.

Nutrients are the “chemical components of food that are capable of performing specific functions related to body’s ability to work, grow, develop and maintain good health when supplied in appropriate amounts.” A diverse diet, i.e. a diet which contains a variety of food items from different food groups can provide us many different nutrients which are needed to perform important functions in the body.

Nutrients can be broadly classified as Macronutrients and Micronutrients – based on the amount in which they are required by our body. Both macronutrients and micronutrients are extremely important for our body as each nutrient has specific roles to play. Carbohydrates, protein, fat and water are considered to be macronutrients, needed by our body in quantities ranging from few grams to kilograms.

Sources of Fat:

Cooking Oil, Ghee, Butter, Fatty Meat

Lipids are a heterogenous group of substances including fats, oils and fat-like substances that are greasy in texture, and soluble in organic solvents. Lipids are concentrated sources of energy in our diet. They are the second largest contributors to energy intake, providing 20 - 30% of the total energy intake. Lipids in our diet are mostly fats (or triglycerides), followed by phospholipids and cholesterol esters. Fats are highly complex compounds composed of carbon, hydrogen & oxygen. They are present in nearly all the foods that we eat, adding a special taste & flavor to the food. Each gram of fat provides 9 kcal. Fatty Acids are the main constituents of all lipids.

Types of Fatty Acids

Fatty acids can be classified in various ways as follows:

1. Based on the degree of saturation

As we have mentioned earlier that fatty acids are the main constituent of fats. Saturation here means that whether the fatty acids contain carbon –carbon double or triple bonds. The fatty acids are classified into two types of fatty acids based on saturation.

· Saturated fatty acids – have no double or triple bonds between the carbon atoms. Oils and fats with saturated fatty acids are solid at room temperature e.g. Ghee, butter, palm kernel oil, coconut oil.

· Unsaturated fatty acids – have one or more double bonds between the carbon atoms.

Ø Monounsaturated fatty acids (MUFA) – have a single double bond in between the carbon atoms e.g. Oleic Acid present in palmolein, groundnut oil, olive oil, sesame oil,cottonseed oil, red palm oil, mustard oil etc.

Ø Polyunsaturated fatty acids (PUFA) – have two or more double bonds between the carbon atoms. Sunflower oil, corn oil & safflower oil are rich sources of PUFA.

Trans fatty acid - An unhealthy isomer, made during the process of hydrogenation of oils. Vanaspati is an example of hydrogenated fat. The naturally occurring isomer of unsaturated fatty acids is the cis form.

2. Based on chain length

Based on the length of the carbon chain, fatty acids can be classified as short, medium and long chain fatty acids.

• Short chain fatty acids are usually less than 6 carbon atoms in length. Examples include butyric acid found in milk fat, ghee and butter. These are rapidly digested and can be directly absorbed from the intestines into the blood circulation.

• Medium chain fatty acids contain between 6 and 10 carbon atoms. Examples include caproic, caprylic and capric acids present in milk fat and also coconut oil and palm, kernel oil, which is considered to be a rich source of medium chain fats. These are also rapidly digested and directly absorbed from the intestines into the blood circulation.

• Long chain fatty acids have 12 or more carbon atoms. These include lauric, myristic, palmitic, stearic, oleic, linoleic and linolenic acids. These are found in all the vegetable oils we use for cooking. Most fatty acids present in animal tissues contain 16-26 carbon atoms.

3. Based on Nutritional properties

· Essential fatty acids – are the ones which are very important for growth & development but cannot be synthesized by the body. Linoleic (omega 6) and linolenic acid (omega 3) are the two essential fatty acids. Thus, they must be supplied by the diet. Rich food sources of essential fatty acids are- soyabean, safflower, sunflower,cotton seed oil, and other cooking oils, oily fish like cod, salmon, cereals and legumes, nuts, etc.

· Non – essential fatty acids – are the ones which can be synthesised in the body & are not required from the diet. Stearic, palmitic & oleic acids are the non-essential fatty acids.

· Fats in our diet can also be classified on the basis of their visibility as:Invisible fats – fats which are a part of foods and hence not visible to the eye for instancethe fat present in fish, milk & milk products, meat, egg, nuts & oilseeds.

· Visible fats – are the added to food during preparation & processing. These are fats that can be seen. e.g. oils, ghee, butter, vanaspati & cream.

Functions of Fats

1.Dietary fat has a very important role to play in our bodies. Fats are the chief source of energy for the body. Excess fat is stored inside the body (in the abdomen, surrounding the organs & laced throughout the muscle tissue) as a reserve of energy to be used in times of need.

2.Fats are concentrated sources of energy. One gram fat provides 9kcal; twice the amount as compared to carbohydrates & proteins. Adding some fat to food increases its energy density, thereby reducing the bulk of the diet. This is especially important for small children who cannot have a large quantity of food at a meal. Example adding some ghee to the dal or kheer served to the small child, willmake it energy dense.

3.Fat is an integral part of the structure of the human body; all body cells contain fat in their cell membranes. Amongst healthy & non-obese men & women; 15-25% of the total body weight is fat.

4.Essential fatty acids and long chain PUFA synthesized from these like EPA, DHA and Arachidonic acid perform vital functions in the body. They lead to formation of other substances in the body which are needed for the regulation of a number of vital functions like blood pressure, blood clotting, immune responses, inflammatory responses and regulation of body temperature, etc. DHA is important for normal development & maturation of the retina of the eye & brain development during the first 1000 days.

5.The stored fat acts like an insulator preventing the body from losing heat easily, thus helping to regulate body temperature.

6.Adipose tissue provides a protective cushioning/ padding around the delicate internal organs of the body such as liver, heart & kidneys.

7.It keeps the gastrointestinal tract lubricated helping in smooth movement of food.

8.Fat provide higher satiety value to the meals as it reduces gastric motility, meaning that the movement of the ingested food out of the stomach slows down thereby giving a feeling of fullness for a longer time.

9.Dietary Fat is required for the absorption of fat soluble vitamins – A, D, E and K. A zero fat diet is considered unhealthy.

10. Fat provides variety & flavour to the food thereby increasing the palatability of the food.

Food Sources of Fats:

Health Significance of Fats

Consuming the right combination of fats & oils in appropriate quantities is important. Ideally calories from fat should be between 20-30% of the total calories, with less than 10% calories coming from saturated fats. Eating too little fat can result in poor absorption of fat soluble vitamins (Vitamins A, D, E & K) as well as overdependence on carbohydrates to provide the energy resulting in a very bulky diet. Unsaturated fatty acids like PUFA and MUFA help to decrease the risk of heart diseases by lowering total cholesterol and LDL (Bad) cholesterol levels. Omega 3 fatty acids prevent inflammation and accumulation of fatty material in blood vessels thus protecting against heart diseases. They also prevent thrombosis or clotting of blood thus reducing the risk of strokes.

On the other hand, excessive intake of fat can lead to weight gain & obesity. There is increased risk of cardiovascular diseases and certain types of cancers. Excessive consumption of saturated fatsraises the total and LDL cholesterol levels. They have also been shown to contribute to insulin resistance. Hence, they increase the risk of heart disease and diabetes. Trans fats also increase the risk of heart disease by increasing LDL cholesterol, decreasing HDL (Good) cholesterol, increasing inflammation and insulin resistance in the body.

Explain the importance, composition and nutritive value of pulses in human diet.

 

Pulses are edible fruits or seeds of pod-bearing plants belonging to the family of the leguminous. The major pulses which find important place in our dietaries are red gram dhal, bengal gram, black gram dhal, green gram dhal and masoor dhal. Some are used as whole grams. Cow pea, rajmah and dry peas also belong to leguminous family.

Pulses are the “poor man’s meat”. Pulses can play an important role in bridging the protein gap. An alternate name for pulses is “legumes”. The term gram is commonly used for dry legume seeds with husk, while split decorticated grains are called “dhal”.

Importance of Pulses:

Pulses are an important source of protein, especially for vegetarians or for people who do not get enough protein by eating meat, fish or dairy. 

Furthermore, pulses are a healthy choice for meat-eaters, helping cut off excess fat from diets, and contain zero cholesterol. 

They are also a good source of dietary fibre, vitamins and minerals, especially iron and zinc.  

In terms of gram-for-gram nutritional value, pulses are also far cheaper than meats or other sources of protein, offering an economical alternative. 

Pulse crops such as lentils, beans, peas and chickpeas are an important source of plant-based proteins and amino acids for humans and animals. They also provide other important nutrients; • Pulses play as part of sustainable food production aimed towards food security and nutrition. They are part of a healthy diet to address all forms of malnutrition • Pulses are thought to have positive effects on the prevention of non- communicable diseases such as obesity, diabetes, coronary conditions and cancer • Pulses are recommended in many dietary guidelines such as Health Canada’s Eating Well with Canada’s Food Guide, the MyPlate system of the United States Department of Agriculture (USDA), the Eatwell Plate of the Food Standards Agency in the UK and Nutrition Australia’s Healthy Living Pyramid • Pulses are an important part of vegetarian diets and are often used as meat replacement.

Composition of Pulses:

Pulses have the same calorific value as that of cereals. However, the protein content and health benefits of pulses are double as that found in cereals.

– The fat content  is about 2 grams of fat for 100 grams of pulses.
– The whole pulses are a significant source of Vitamin B complex.
-The amount of iron present in pulses is high. It has about 10.
– Pulses have about 60 grams of carbs for every 100 grams of pulses.
-the amount of calcium present in pulses is about 100 to 200 mg for every 100 grams of pulses.
-pulses have zinc
-copper present
-some pulses also have magnesium

 

Nutritive Value of Pulses:

i. Energy: Pulses give 340 calories per 100g which is almost similar to cereal calorie value.

ii. Protein: In a vegetarian diet, pulses are important sources of protein. They give about 20-25 percent protein. The proteins of pulses are of low quality since they are deficient in methionine and tryptophan. Pulses are rich in lysine. The most effective combination to achieve maximum supplementary effect is 5 parts of cereal proteins and one part of pulse protein. In terms of grains 8 parts of cereals and 1 part of pulses. This combination gives a protein quality equivalent to animal protein.

iii. Carbohydrates: Pulses contain 55 to 60 percent starch. Soluble sugars, fibre and unavailable carbohydrates are also present.

iv. Lipids: Pulses contain 1.5 per cent lipids on moisture free basis. They contain high amounts of polyunsaturated fatty acids. Along with cereals, they meet the requirements of essential fatty acids for an adult. Apart from linoleic acid, most legume seed oils contain high proportion of linolenic acid. They undergo oxidative rancidity during storage resulting in loss of protein solubility, off flavour development and loss of nutritive quality. Oleic, stearic and palmitic acids are also present.

v. Minerals: Pulses are important sources of calcium, magnesium, zinc, iron, potassium and phosphorus; 80 per cent of phosphorus is present as phytate phosphorus. Phytin complexes with proteins and minerals and renders them biologically unavailable to human beings and animals. Processing such as cooking, soaking, germination and fermentation can reduce or eliminate appreciable amounts of phytin.

vi. Vitamins:Legume seeds are excellent source of B complex vitamins particularly thiamine, folic acid and pantothenic acid. Like cereals they do not contain any vitamin A or C but germinated legumes contain some vitamin C.

Conclusion:

India is the largest producer of pulses in the world, yet it is also the largest importer of pulses. The issue with India is that it is more vegetarian than any other society in the world and pulses are also the most economic source of protein for Indians. Consequently, our dietary dependence on pulses as the main source of protein is enormous.