| Food has been a basic part of our existence. Through the centuries we have acquired a wealth of information about the use of food as a part of our community, social, cultural and religious life. Foods have been grouped depending upon the nutrient content. They are: |
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| Cereals grains : These include rice, wheat, ragi, bajra, maize, jowar, barley. |
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| Pulses and legumes : These include Bengal gram, black gram, green gram, red gram, lenthil (whole as well as dhals), peas, rajma etc. |
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| Fruits : These include mango, guava, papaya, orange, water melon etc. |
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| Vegetables : These include green leafy vegetables (eg. amaranth, spinach, fenugreek leaves, coriander et), root vegetables (like potato, yam, sweet potato etc) and other vegetables such as brinjal, ladies finger, capsicum, drumstick etc. |
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| Milk and milk products : These includes milk, curd, cheese, chicken, egg, meat, fish, etc. |
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| Meat, fish and poultry. |
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| Fats and oils : These includes butter, ghee, hydrogenated fat, cooking oils like groundnut, mustard, coconut etc. |
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| Sugars : This includes sugar and jaggery. |
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| Carbohydrates, proteins, fats, minerals, and vitamins are the six major components of food. To maintain food health, ingesting a diet containing these nutrients in correct amounts is essential. A balanced diet is one which contains different types of foods in such quantities and proportions so that the need for calories, proteins, minerals and vitamins is adequately met and a small provision is made for extra nutrients to withstand short duration of leanness. |
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| Carbohydrates : Starch found in cereals and sugar in sugarcane and fruits are example of carbohydrates in foods. |
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| The chief function of carbohydrates is to provide energy needed by our body. |
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| Those not used immediately for this purpose are stored as glycogen or converted to fat and stored, to be mobilized for energy supply when needed. |
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| Proteins : Casein in milk, albumin in egg and gluten in wheat are examples of proteins occurring in foods. |
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| The main function of protein is the building of new tissues and maintaining and repair of those already built. |
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| Regulatory and protective substances such as enzymes, hormones and antibodies are formed from food proteins. |
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| About 10 % of the total energy is supplies by proteins in the diet. |
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| Protein, when taken in excess of the body’s need, is converted to carbohydrates and fats and is stored. |
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| Fats : Oils found in seeds, butter from milk, and lard from meat are examples of fat found in foods. |
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| Fat are concentrated sources of energy, carrier of fat soluble vitamins and essential fatty acids. |
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| If excess fats are taken in the diet, these are stored as fat reserves in the body. |
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| Energy taken in excess of body needs, be it from carbohydrates, fats or proteins, is stored as fat in the body. |
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| Minerals : Calcium, phosphorous, iron, iodine, sodium and other are the examples of minerals formed in various foods. |
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| Minerals are necessary for body-building, for building of bones, teeth and structural parts of soft tissue. |
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| They also play a role in regulation of processes in the body, e.g. muscle contraction. |
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| Vitamins : Fat soluble vitamins A, D, E, K and water soluble vitamins C and B group are found in foods. |
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| These are needed for growth, normal function and normal body processes. Certain vitamins also acts as antioxidants. |
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| Antioxidant : Antioxidants are compounds that protect cells against the damaging effects of reactive oxygen species, such as singlet oxygen, superoxide, peroxyl radicals, hydroxyl radicals and peroxynitrite. An imbalance between antioxidants and reactive oxygen species results in oxidative stress, leading to cellular damage. Oxidative stress has been linked to cancer, aging, atherosclerosis, ischemic injury, inflammation and neurodegenerative diseases (Parkinson's and Alzheimer's). Some enzymes such as glutathione peroxidase, catalase produced during normal metabolism can act as antioxidants in the body. The recognized dietary antioxidants which helps against free radical damage are vitamin E, vitamin C, selenium and carotenoids. |
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| Free radical : Free radials are reactive species which have one or more extra free floating electrons, rather than having all matched pairs, and are therefore unstable and highly reactive. |
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| Fibre : Dietary fibre is defined as that part of plant material in our diet which is resistant to digestion. |
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| Cellulose, hemicellulose and pectins which are components of the skins of fruits, covering of seeds and the structural parts of edible plants are usually referred to as ‘fibre’. |
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| Fibre has the ability to absorb water, thereby serving a useful purpose in helping with the elimination of intestinal wastes. |
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| They stimulate the peristaltic (rhythmic) movements of the gastrointestinal tract by adding bulk to the intestinal contents. |
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| Flavonoids : Flavonoids are polyphenolic compounds found in fruits, vegetables, and certain beverages (tea, coffee, beer, wine and fruit drinks) that have diverse beneficial biochemical and antioxidant effects. Their dietary intake is quite high compared to other dietary antioxidants like vitamins C and E. |
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| The flavonoids have been reported to have antiviral, anti-allergic, anti-platelet, anti-inflammatory, antitumor and antioxidant activities. |
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| Flavonoids may help provide protection against diseases caused by oxidative stress by contributing, along with antioxidant vitamins and enzymes, to the total antioxidant defense system of the human body. |
