By-Dr. Santosh Jain Passi : Adequate food, clothing and shelter are the basic necessities of life of which, food is the most important one. Food not only satisfies hunger but also provides nutrients for various activities and keeps us healthy. Food, after ingestion, digestion and absorption is capable of being utilized by the body for its various functions. It provides the nutrients to maintain body functions and health.
Nutrition is the science of food and its relationship to health. The concept of health as defined by the World Health Organisation is, “the state of complete physical, social and mental well being and not merely absence of disease or infirmity. Nutrition and health are not synonymous, but without good nutrition, health cannot be at its best.
Nutrition is the science which deals with the nature and distribution of nutrients in food, their metabolic effects and the consequences of inadequate food intake.
Nutrients are chemical compounds in foods that are absorbed and used to promote health. Some nutrients are essential because they cannot be synthesized by the body and thus must be derived from the diet. Essential nutrients include vitamins, minerals, amino acids, fatty acids and some carbohydrates as sources of energy. Non-essential nutrients are those that the body can synthesize from other compounds, although they may also be derived from the diet.
Nutrients are generally divided into macronutrients and micronutrients. Macronutrients constitute the bulk of the diet and supply energy as well as essential nutrients needed for growth maintenance and activity. Carbohydrates, facts, proteins, macro minerals and water are macronutrients. Micronutrients include vitamins (both water soluble and fat soluble) and essential trace minerals. Adequate supply of these nutrients is the fundamental basic requirement for positive health, functional efficiency and productivity.
Intake of good and adequate food enhances nutritional status and consequently the health of the human being. Good and adequate food is that which provides all the nutrients according to the needs of the body. Good nutrition through a well balanced diet provides essential and non-essential nutrients in correct balance, which are further utilized to promote the highest level of physical and mental health.
Nutrition is important not only for promoting proper physical growth and development but also for ensuring adequate immuno-competence and cognitive development.
Vegetarian diets are more nutritious. Plant products are rich sources of complex carbohydrates (dietary fibre), vitamins like B-carotene, vitamin E, ascorbic acid, thiamin, riboflavin and folic acid; and several minerals particularly iron, calcium, sodium, potassium and iodine. They are also rich sources of phytochemicals and antioxidants. Moreover, most of the foodstuffs from plant origin (except oils and oilseeds) do not contain high quantity of fat; and the fat present is, to a greater extent is rich in unsaturated fatty acids – MUFAs and PUFAs ; which are rather essential for maintaining good health and some of them are therefore named as essential fatty acids. Vegetarian foodstuffs do not contain cholesterol.
Vegetarianism can help in the prevention of coronary artery diseases by keeping the blood cholesterol levels within normal range. Liver is the chief site of cholesterol synthesis in our body. A part of cholesterol synthesized in the liver gets incorporated into bile acids and bile salts. Bile is secreted in the gut to help digestion and absorption of food. It is reabsorbed and taken up by the liver after digestion of food. Dietary fibre interrupts this cycle by preventing reabsorption of bile salts from the gut. The latter are then excreted with undigested food. By enhancing cholesterol excretion, fibre also reduces the availability of cholesterol in the liver for incorporating into cholesterol rich particles (lipoproteins) for release in the circulating blood. Recently it has also been proposed that fermentation of fibre by the intestinal bacteria results in the formation of short chain fatty acids (SFAcs) which may inhibit cholesterol synthesis in the liver. This is attributable to the fact that whole cereals, pulses (with husk) and several fruits and vegetables are rich sources of dietary fibre.
Further fruits and vegetables are rich sources of B-carotene, vitamin E, vitamin C and phytochemicals which have antioxidant properties i.e. they prevent oxidation of blood cholesterol which is the principal form of cholesterol that gets deposited in the walls of our arteries. These cardio-protective agents also prevent cellular damage caused by free radicals and hence can be helpful in increasing the cell life.
Vegetarian diets can also help in the treatment/management of diabetes. Dietary fibre regulates the rate of glucose absorption from the gut thereby preventing a peak rise in blood glucose after meals. The sharp drop in blood glucose during the in-between meal times can also be prevented because fibre delays gastric emptying. Further, chromium and certain vitamins have been found to be associated with improved insulin efficiency. Thus, vegetarian diets can help in improved glucose tolerance and reduce the requirement of drugs/insulin in certain patients.
A vegetarian diet can help in reducing the risk of suffering from cancer because dietary fibre gets bound to several chemicals/toxic agents and results in their excretion. Several vitamins and minerals also help in maintaining the integrity of the cell walls thereby preventing damage to various cell components such as DNA and RNA which may initiate the tumor process.
Consumption of plant foods also reduces the chances of developing hypertension. Fibre present in plant foods, gets bound to some amount of dietary sodium and results in its excretion. Being low in saturated fats and not containing cholesterol, plant foods prevent a rise in blood cholesterol. Hypercholesterolemia results in the deposition of cholesterol in the arteries and indirectly causes elevation of blood pressure.
Vegetarian meals provide a greater feeling of satiety/stomach fullness and this is helpful in weight management.
Research studies have indicated that incorporating soluble fibre such as 15 grams guar-gum (obtained from the seeds of cluster beans) in the daily dietaries for a period of four weeks can help in reducing total cholesterol by 13 per cent and post-prandial blood glucose by 21 per cent. Substituting 50 gram of whole bengal gram flour for wheat flour can help in reducing total cholesterol by 6.2 per cent. Similar positive effects have been observed in case of soyaflour and oat bran supplementation.
However, a purely vegetarian diet, which does not include milk and milk products can be low in proteins. The major sources of protein in plant foods are pulses and nuts. Cereals are moderate sources, while fruits and vegetables are poor sources. Therefore to ensure an adequate intake of protein in the diet one must consume atleast 2-3 servings of whole pulses and a few nuts (almonds). Sprouting of whole pulses, incorporating cereal pulse combinations and fermentation of cereals and pulses can help in improving the bio-availability of proteins and hence help in balancing the diet.
Vegetarianism offers many health benefits. In view of the currently prevalent lifestyle and dietary errors it is a good option to adopt vegetarianism for maintaining good health.