Nutrition in Humans

For healthy growth and development of the body, you need to eat food that provides enough of all essential nutrients. Nutrients are the chemical substances present in the food which nourish the body.

Nutrients are broadly divided into three groups:

  1. Energy-yielding nutrients: carbohydrates and fats

  2. Body-building nutrients: proteins

  3. Growth-regulating nutrients: vitamins and minerals

1. Carbohydrates

Carbohydrates are the main source of energy. Carbohydrates may be in the form of sugars, starch or cellulose.

  • Sugar: Fruits, milk, sugarcane

  • Starch: Potato, wheat, rice, sweet potato

  • Cellulose (Roughage): Salads and raw vegetables

2. Fats

Fats keep the body warm and help in the transport of fat-soluble vitamins. Some common sources of fats are edible oil, ghee, butter, meat and nuts like groundnuts. One gram of fat on oxidation given about 37 kilo joules (9 kilocalorie) of energy.

3. Proteins

Growth of body tissues is the main function of proteins. A glass of milk or a bowl of cooked pulses (dals) or an egg are rich in proteins.

4. Vitamins

Vitamins are necessary for normal growth, and maintenance of the body, and are required in relatively small amounts. Deficiency of a particular vitamin causes disease. Overdose of certain vitamins, such as vitamins A and D, is harmful. Vitamins may be water-soluble or fat-soluble.

  • Water-soluble: Vitamins B-complex (B1, B2, B4, B12) and C
  • Fat-soluble: Vitamins A, D, E and K

5. Minerals

Minerals such as iron, calcium, sodium, potassium, and iodine are required by the body in small quantities.

6. Dietary Fibres

Dietary fibres are also known as roughage. Roughage is mainly provided by plant products. Whole grains and pulses, potatoes, fresh fruits and vegetables are main sources of roughage. Roughage does not provide any nutrient to our body, but is an essential component of our food and adds to its bulk. This helps our body get rid of undigested food, helps in bowel movement and prevents constipation.

7. Water

Water is an important part of diet. It makes 65-70% of the body weight. Water regulates the body temperature, and provides is a medium for biochemical reactions taking place in the body. It also helps in throwing out some wastes from body as urine and sweat.

Balanced Diet

For healthy growth and development, you need to eat foods that provide all the essential nutrients in the correct proportion. Eating a variety of foods in proper quantity everyday constitutes a balanced diet. A balanced diet contains adequate amounts of essential nutrients such as carbohydrates, fats, proteins, vitamins, minerals and water.