Nutritive value of Indian foods – Due to marked geographic variations in India, It is important to consider local food preferences, availability and affordability, while offering nutritional counseling. Nutritive value of Indian foods are discussed here. All protein and caloric values in the following discussion are given as in 100 gm or ml of foodstuff, unless specified otherwise.
Cereals form the bulk of diet and contribute >70% and >50% of daily calories and protein intake; respectively. In general, cereals are rich sources of energy (350 cal) proteins (12 gm; except rice), Vitamin B complex and minerals. However, cereal proteins are deficient in lysine.
Rice is the staple food for over half of the world population. Although it contains less protein (7 gm %) than other cereals, rice protein is of better quality due to higher lysine content. Milling and cooking with excessive water significantly reduces its Vitamin B complex content (present in its outer coating) which may be avoided by promoting the use of un-husked or parboiled rice. Thiamine deficiency like Ben-ben is more common in rice-staple population.
Parboiling is a process to preserve the nutritive value of rice by moving its vitamin content from outer coating to inner endosperm, It involves soaking the un-husked rice in hot water (65-70°) for 3-4 hours, followed by steaming for 5-10 minutes, before drying and storing/milling.
Wheat, the second commonest staple cereal, is deficient in lysine and threonine. Whole grain wheat flour (Aata) is more nutritious than white flour (maida) due to loss of Vitamin B content during milling.
Maize ranks third in world cereal consumption. Apart from lysine it is also deficient in trytophan – a niacin precursor, and pellagra is common in maize-staple population. Some strains of maize also contain excess leucine that interferes with conversion of tryptophan to niacin in body.
Millets are smaller grains like thwar (sorghum), Bajra (pearl millet), Ragi etc, with caloric and protein value equal to cereals i.e. — 350 cal and 10-12gm of proteins (except Ragi). Millet proteins are deficient in lysine and threonine.
Ragi, low-cost popular millet provides lesser calories (325 cal) and proteins (7 gm), but is a very rich source of calcium.
Pulses or Legumes include Grams like Bengal-gram (Chana), green-gram (Moong), red-gram (Arher) and black-gram (Ural) and Beans like Soya bean and pea.
All grams provide -. 350 cal (equal to cereals), apart from proteins, Vitamin B complex and minerals. Pulses are very rich sources of proteins (20-25 gm) in vegetarian diet, often termed as poor man’s meat. Nutritive value of Indian foods of pulses may be further enhanced by ‘Germination’ that increases Vitamin B & C content.
However, pulse-proteins are deficient in methionine and cysteine. In addition, uncooked pulses also contain some anti-nutrient factors like phytates and tannins, which inhibit absorption of other nutrients like iron.
Soya bean is a very rich source of protein (42 gm), though deficient in methionine. Soya-milk is also used as infant feed during lactose intolerance.
Vegetables are considered as protective foods (along with fruits) due to their high vitamin and mineral content.
Green leafy vegetables are essential in diet due to high Vitamin B (except B12), A and C content; high iron and calcium content, high fiber and water content and low caloric value (25-50 cal) i.e. anti-obesity effect.
Other vegetables like potato, carrots, onion, radish etc. are of limited nutritive value, except to increase palatability of diet. However, some of them are good sources of vitamins like carrot (Vitamin A) or minerals like iron (radish, drum sticks). Roots & tubers like potato, sweat-potato and tapioca are rich in carbohydrates.
Fruits are valuable due to high vitamin content like Vitamin A (papaya and mango), Vitamin C (amla), High mineral content like calcium (custard apple) and potassium (coconut water), high caloric value like banana (100 cal), custard apple etc., High cellulose content (anti-constipating effect).
Dry fruits like dates, raisins and apricot are rich sources of calories, iron and calcium.
Nuts & oil seeds like groundnut, coconut, mustard on sunflower seeds are rich sources of fats.
Groundnut is a very rich source of calories (-.550 cal) proteins (25-30 gm), also called as poor man’s cashew nut. Even after oil extraction, groundnut flour retains its protein value and has been used to make supplementary foods like Balahar.
Dry nuts like cashew nut, walnut, almonds, pistachio contain more fat than groundnut (35-65%), but less proteins. These nuts are good but costly source of minerals like calcium, phosphorus and iron.
Milk is the wholesome food for all ages, being rich and quality source of most nutrients. Breast-feeding is the best source of nutrition in early infancy. Other milks may be divided into two categories animal milk, modified milk preparations like skimmed milk, toned milk, evaporated milk, dried milk powders etc.
a) Animal milk: Composition of various animal milks differs significantly, as follows:
• Cow milk has a composition nearest to human milk with some differences (Table 5.4) and hence, commonly used for top feeding in infants, if necessary.
* All approximate values, may vary with cooking practices and size of utensils. Standard size of utensils: Teaspoon: 5 ml, Tablespoon: 15 ml, Cup: 150 ml, Katori: 150 ml, Glass: 250 ml
• Buffalo milk has very high fat and caloric content and hence, should be used only after proper dilution, especially in infancy.
• Goat milk, though better digestible than the cow milk (less curd formation), is deficient in folic acid (megaloblastic anemia) and carries additional risk of causing brucellosis, if used without boiling.
As animal milk is regularly contaminated, boiling is essential before consumption. Currently all marketed milks are pasteurized for this purpose.
Pasteurization involves heating of raw milk at 63° for 30 minutes (or 72° for 15 seconds) followed by rapid cooling, to eliminate all pathogenic bacteria and reduce non-pathogenic bacterial count <50,000/mi. Pasteurization also improves digestibility of case in with less curd formation.
b) Modified milk preparations include —
• Skimmed milk is available in liquid and dried form (milk powders), prepared after removing most of the cream from animal milk, with fat content of 0.5% in full-skimmed milk or 1.5% in half-skimmed milk.
• Toned milk, cheapest milk, is prepared by mixing natural milk, water and milk powder (1:1:8) followed by pasteurization before packaging. It has composition similar to cow milk.
• Evaporated milks are commercial available as concentrated milk in liquid form, with long shelf-life for many months.
Skimmed milk and evaporated milk should not be used for infant feeding due to high protein and mineral content that may cause dehydration. However, these milks are useful as a dietary supplement for older children during fresh milk shortage.
Commercial milk formulas, modified according to the age-related requirements and fortified with various nutrients are available for top feeding, though these are costly and require careful reconstitution.
Eggs are known for their quality protein content (6 gm/ egg), containing all essential amino acids. Egg protein is considered as ideal or reference protein (NPU —96), with whom other proteins are compared. Milk and meat protein has an NPU of 75 and 80 respectively, while vegetable proteins have even lower NPU i.e. — 60-65%.
Boiled egg is better than raw egg as boiling destroys ‘avidin’ – a substance that prevents biotin absorption. Eggs are also rich sources of energy (70 cal), vitamins (except Vitamin C) and minerals.
Sea-foods including fishes, are rich in quality proteins (15-25 gm%), unsaturated fatty acids, fat-soluble vitamins and minerals like calcium, phosphorus and fluorine. Sea fish/foods also contain iodine that is deficient in fresh-water fishes. However, fish contains very little carbohydrates.
Meat & animal organs like liver, are good sources of quality proteins (15-20 gm%), vitamins like Vitamin D & B complex, minerals like iron, zinc (but deficient in calcium).
Fats & oils are good sources of energy (9 cal/gm) and increase palatability of diet.
Vegetable oils are rich in EFA and PUPA (except coconut and palm oil), but contain little Vitamin A & D, unless fortified (vanaspati ghee). High PUPA content in vegetable oils limits hypercholesterolemia, obesity and consequent health problems. Coconut oil is rich in triglycerides, which are absorbed directly without micelles formation (bile-based absorption) and hence, useful source of energy in pre-terms and chronic liver disease.
Animal fats lack EPA and mainly contain saturated fatty acids with obesity-effect. However, animal fats are useful source of energy in malnourished children and contain plenty of fat-soluble vitamins.
Other food products like sugar, condiments/spices and beverages have very limited dietary value, except to increase its palatability.