In order to survive, humans have developed a very complex system of eating and living. Food plays a very important role in the diet of a human being. The word “food” literally means “food”. Food is food used to give nutrition to an organisms, to enable him/her to carry out his functions normally. In simple words, food is the primary source of nourishment for man. It comprises all the meals we eat, in which protein, carbohydrates, fat, vitamins and minerals are the principal elements.

Protein, carbohydrates, vitamins, minerals and fibers constitute the main constituents of food energy. Carbohydrates are the main source of energy in our daily energy needs. These include rice, wheat, cereals, pasta, potatoes, pulse, seeds, nuts, fruits, vegetables and legumes. Fruits constitute the largest group of carbohydrates and are available fresh or dried. Oats, beans, grains, bread, noodles, cereals, beans, pulses, fish, meat, milk, cheese, diary, butter, cheese, milk, sugar, honey and fruit juice constitute the supply of nitrogen for carbohydrates.

Proteins are the major component of food energy. Protein is made up of amino acids and is found in animal products (meat, milk, eggs, fish and poultry), vegetables and fruits. The five main protein components of the body – albumin, globulins, pectins, whey and cholesterol – combine in the digestive tract of animals and humans to digest protein. Some of the other nutrients that are important for the body’s health and may be included in the diet are vitamins A, C, D, E and K, beta-carotene, minerals magnesium, boron, iodine and potassium.

Vitamins, too, are important to maintain good health. Milk is the only exception to this rule as vitamin D is primarily produced by sunlight. However, milk products contain other nutrients that are vital to human health. Some of these include calcium, which is needed to strengthen bones; vitamin A, vitamin B-complex and vitamin D. Beta-carotene and lycopene, an essential fat-soluble vitamin are obtained from foods such as carrots, cantaloupe and spinach. Fruits and vegetables also provide a wide range of other nutrients including antioxidants, dietary fibers, carotenoids, flavonoids and other polyphenols.

Other than vitamins, food sources of vitamin B-complex include liver, egg yolk, provitamin B-12 and other dairy products. Vitamin C improves immune function and is needed for collagen formation. Folic acid, iron and other trace minerals are also important for good health.

Many food sources of vitamin A are liver, spinach, green peppers, strawberries, oranges, cantaloupe, tomatoes, carrots, peaches and other fruits and vegetables. Some vitamin A occurs naturally in animal products like liver, kidney and beef. Vitamin B-complex comes primarily from animal source foods and includes eggs, dairy products, milk products. Vitamin D occurs in fortified milk and orange juice. Since most American diets do not provide a wide variety of these vitamins and minerals, it is important to eat a wide variety of fruits and vegetables.