Food Groups in Human Nutrition

Variety in food is very important for the maintenace of good health and prevention of disease. Fats, lipids, carbohydrates, minerals, trace elements, vitamins and water must all be present in moderate ammounts in the daily diet. Recommended daily allowances (RDA) represent a refence base for nutrition intake. RDA vary in different countries, and they do not indicate individual requirements or clinical needs.

A healthy diet should consist of varying amounts of the following food groups: cereals, legumes, vegetables, fruit, meat, fish and sea foods, eggs, milk and milk products, fats and oils, beverages.

Cereals Cereals are the staple food of most diet, providing 2/3 of the energy intake in developed countries. The major cereal grains are wheat, rice and corn. Cereals are an important source of carbohydrates, protein, minerals, vitamins, and fiber. Other cereals include barley, sorghum, millet, oat, rye. Corser flours are much richer in vitamins and nutrients than more refined flours. Maize is low in niacin, which is the reason why poplulations relying mainly on maize have cases of pellagra. Maize is also low in tryiptophan which can be converted into niacin by the body. Rice has comparatively high level of essential amino acids among other cereals. Poputions relying primary on rice as a source of energy exhibit more frequent cases of Beri Beri (Vitamin B1 deficiency).

Legumes

Vegetables Potato, yam and sweet potato are major sources of carbohydrates, protein, vitamin C, and beta carotene. The high amounts of potato consumed in the czech republic make it a mjor source of vitamin C. Potato provides 300 kJ of energy per 100g. These vegetables are tubers, underground organs of many plants. Root crops such as turnips, carrots, parsnips, cassava beetroots, and sugar beet, have high water and carbohydrate content, but low content of other nutrients. Carrots are an exception, containing high ammounts of carotenoids. Leafy vegetables contain a low energy content. They contain proteins, sugar, and cell wall material, but at low weights. Their main significance in the diet is their high content of vitamins (vit. C, folates, minor ammounts of B vitamins). They contain a range of trace elements and a significant amount of magnesium and potassium. Onions have a similar composition of nutrients. Fruits Fruits are high in water content. They contain glucose, fructose and sucrose. They are primarily sources of vitamins, namely vitamin C. Green and yellow colored fruits are significant sources of vitamin C. Meat Meats are an important source of a protein fat in the diet. The composition of all meats is dependent on the ratio of fat to lean. Iron levels are high in meat. They are an important source of vitamins, especially B12. Fat soluble vitamins are present in the fat. Fish and Sea Foods Fish and seafood have been an important source of nutrients in communities living close to the sea. They are a source of good quality protein, low amounts of fat with long chain polyunsaturated fatty acids. Fishes are in important source of iodine. Eggs Milk and milk products The major protein in milk is casein. The other proteins are lactalbumin and immunoglobulins. It contains a high lysin content, which means that it is very well supplement with cereals. Allergic reaction to milk products is one of the most common type of food intolerance. Milk contains both fat and water soluble vitamins.

Fats and Oils OIls are fluid at ambient temperatures, while fats are solid. They are the richest source of energy with a an energy value of 36kJ/g. They provide the essential fatty acid and contribute to the absorption of the fat-soluble vitamins. Beverages Water is an essential component of the human diet, required to maintain hydration of tissues. Soft drinks are very limited in nutrition value with very high concentration of sugar. Fruit juices are rucg in vitamins, namely vitamin C.