PROTEIN

Protein is a macro-nutrient required mainly for growth and repair functions of body. They also provide energy when stores of carbohydrates and fats are diminished. They produce 4 calories per gram which is equal to that of carbohydrates and half that of fats. Proteins are made up of amino acids. There are 20 amino acids present in human body out of which about half are essential amino acids. These essential amino acids should be taken from diet as the body cannot produce them by itself. 

Sources of Protein

Proteins are present in both animal and plant foods. They are abundant in meat, eggs, milk, fish, cereals, pulses, nuts etc. Animal proteins are better than plant proteins as all the essential amino acids are present in animal proteins in appropriate amount while plant proteins usually lack one or more amino acids. E.g. cereals lack the essential amino acid lysine while pulses are deficient in another essential amino acid methionine. The combination of both cereals and pulses can be a good trick for vegetarians but even than they’re not as good source of protein as animal proteins due to difference in quantity of different amino acids while they’re present in appropriate amount in animal protein. Therefore, a diet should constitute some animal proteins to remain healthy. 

Importance of Protein

·         Proteins are major constituents of muscles, bones, skin, hair, blood cells, immune system, many hormones, enzymes etc.

·         Proteins are the second most abundant kind of molecules in the body after water.

·         A healthy male between 19-70 years of age requires 56 grams of protein per day for remaining healthy while women of same age needs 46 grams of protein per day.

Protein during Exercise

The normal value for protein required by the body is 0.8 g/kg body weight. During exercise, this normal amount should be increased to repair the damage caused by hard exercise. Normal Aerobic exercise or endurance training don’t cause much wear and tear to body muscles but if they’re exercised for prolonged  time than it is  required to repair muscle break down by consuming extra amount of proteins in their diet. They should consume protein a maximum of 1.4 g/kg body weight.

On the other side, Anaerobic exercise or strength training cause much wear and tear to body muscles and large quantity of proteins are required along with anaerobic exercise to repair damaged muscle cells. The strength trainers should consume a maximum protein of 1.8 g/kg body weight to repair amino acid loss and enhance the synthesis of muscle protein. Doing strength training without taking extra amount of good proteins can be very harmful for body. 

Protein Deficiency

Severe protein deficiency can cause general learning disability and kwashiorkor (especially in children). The symptoms of kwashiorkor include fatty liver, diarrhea, apathy, swelling of belly, flaky skin etc. proteins are required by many parts and systems of body as mentioned above, so performance of all these organs and systems decreases with decrease in protein intake or consuming low quality protein (vegetarians who consume no animal foods).

Hormones effects on Protein Metabolism

Many hormones increase the retention of proteins (anabolism) in the body. These include growth hormone, insulin, testosterone and estrogen while few cause their breakdown (catabolism). Cortisol is most important among them. 

FATS & OILS

Fats & oils are macro-nutrients needed by human body to produce energy and perform different body functions. Fats are solid at room temperature while oils are liquid at room temperature. They both are collectively called lipids. Lipids mostly include triglycerides (neutral fat), phospholipids and cholesterol.

Triglycerides are used to provide energy to the body while phospholipids and cholesterol are used to form membranes of all body cells and also to perform other functions of cells. Cholesterol are also precursors to many hormones.

There are three main types of fats present in the food. These are: saturated fat, unsaturated fat and Trans fat. Saturated and unsaturated fats are naturally present in different foods while trans fats are made by hydrogenation of vegetable oils. 

Storage of Fats

Additional triglycerides are stored in the adipose or fat tissues of body. They remain inside the adipose tissue in liquid form and can be easily transported to blood when required. These cells also help to heat insulate the body during cold. 

Importance of Fats

·       Fats provide 9 calories/gram energy which is more than double to carbohydrates (4 calories/gram).

·         Cholesterol are precursors to many hormones including testosterone, estrogen, cortisol etc.

·         Vitamin A, Vitamin D, Vitamin E and Vitamin K are fat-soluble vitamins and they can only be digested, stored and transported through fats.

·         Fats promote healthy cell function, insulate body organs and maintain normal body temperature during cold weather.

·         Fats promote sebum production and thus maintain healthy skin and hair growth.

·         Fats protect vital organs like kidneys against physical shock etc.

Precautionary Measures

High intake of fats especially saturated and trans fats are very injurious for health. They can cause obesity, high blood pressure, atherosclerosis (development of plaque on arterial walls) and also few types of cancer including colon cancer. Therefore, their quantity in the food should be minimized to low levels. Oils should be given preference over fats as they’re easily digestible and transportable in the body. 

Presence in Foods

Most of the foods contain both saturated and unsaturated fats but saturated fats are more abundant in animal foods including cream, butter, egg yolk, fatty meat etc and few vegetable foods including coconut oil, palm kernel oil, cottonseed oil etc. Unsaturated fats are present mostly in plant foods e.g. canola oil, soybean oil, olive oil, sunflower oil, corn oil etc and also in few animal foods especially oily fish. 

Essential Fatty Acids

There are two types of unsaturated fats: monounsaturated and polyunsaturated fats. Omega-3 fatty acids and Omega-6 fatty acids are two essential fatty acids that should be taken by every individual in the food to remain healthy. These two essential fatty acids are present in oily fish, canola oil, pumpkin seeds, sunflower oil, walnuts etc. 

CARBOHYDRATES

Carbohydrates are one of the macro-nutrients, needed by body in larger amounts for energy production. They provide 4 calories of energy per gram. They are made from carbon, hydrogen and oxygen atoms. There are three main types of carbohydrates present in food. These are monosaccharide, disaccharides and polysaccharides.

Monosaccharide or simple sugars are sweet in taste and present in sugary foods. They are the simplest kind of carbohydrates and can’t be hydrolyzed further. Therefore, they provide instant energy to the body. They are naturally present in large amounts in fruits, honey etc. Their main forms are glucose (present especially in grapes and other fruits) and fructose (present in honey, molasses and fruits).  

Disaccharides or complex sugars are made from joining of two monosaccharides. The two main types of disaccharides are sucrose and lactose. Sucrose is present in sugar-cane and made from the combination of glucose and fructose. Lactose is present in the mammalian milk and composed of glucose and galactose. Lactose is less sweet than sucrose due to the presence of galactose.

Polysaccharides or starches are carbohydrates that are produced by joining of large number of monosaccharide. They are complex carbohydrates therefore their digestion and release of energy is slower than sugars. They are most commonly found in cereals (wheat, rice, maize, oats), pulses (chickpea, mung, lentils), peas, beans, bananas, potatoes, nuts etc. 

Body Storage of Carbohydrates

If carbohydrates are consumed in amounts more than required to produce energy, then these extra carbohydrates are stored in body as glycogen or fat. Glycogen is mostly stored in muscles and liver. When the maximum amount of glycogen is stored in body (12-24 hours energy supply), then additional carbohydrates are converted in liver into fats and stored in fat cells. 

Healthy Tips

·         Simple sugars, especially glucose, should be used when instant energy is required for body. It is also used in hospitals to supply instant energy to several patients.

·         World Health Organization (WHO) recommends acquiring more than 50% of total energy from carbohydrates but it should not be more than 10% from sugars.

·         Diabetic patients should avoid sugars in their food as it triggers the glucose level in blood. They can get energy from starchy foods.

·         Starchy foods are also good source of dietary fibers. They keep the GIT healthy.

·         Carbohydrates also satiate the body.