Malnutrition results from an unbalanced diet, this can be due to an excess of some dietary components and lack of other components, not just a complete lack of food. Too much of one component can be as much harm to the body as too little. Nowadays we have enough food to eat and keep our healthy body, but we still suffer from diseases. So I will focus on the result of lack of a specific nutrition especially vitamin and mineral deficiency.
Energy is provided by carbohydrates, fats and proteins. We also need much smaller amounts of other nutrients, such as vitamins and minerals. Because much smaller quantities are needed for a balanced diet these are known as micronutrients. Despite the small quantities needed these are essential to provide a healthy diet as they have specific roles in metabolic reactions and as structural components.
Vitamin
Vitamins cannot be made in the body so must be supplied by diet. Vitamins have no common structure or function but are essential in small amounts for the body to be able to utilise other dietary components efficiently.
Vitamins fall into two categories, fat soluble vitamins such as vitamin A, D, E and K which are ingested with fatty foods and water soluble vitamins such as the B group vitamins and vitamin C. Vitamins are known as micronutrients because only small quantities are required for a healthy diet, in fact fat soluble vitamins can be toxic in high concentrations, for example the body stores vitamin A, or retinol, in the liver as it is toxic if kept in high
Bibliography: Understanding Biology – Glenn Toole and Susan Toole Publisher: Nelson Thornes 7 Dec 1999 Biology a functional approach - Michael Roberts Publisher: Nelson Thornes 18 Sep 1986 http://www.food.gov.uk