Macro and micronutrients
B. Micronutrients
I. Vitamins:
Vitamins are indispensable, non-caloric organic compounds / substances/ needed in small amounts in the diet for growth, health and reproduction, in general, are necessary for the body to function normally. They are referred as protective foods because they function as a vital factor for cellular activity and immunity.
Most vitamins cannot be synthesised in the body, therefore; they have to be supplied with food. Some vitamins can be synthesised by the body in the amount not sufficient for the body demand. E.g.. Vitamin K and B12 are synthesised by intestinal microorganisms but not in adequate amount.
Classification of vitamins: vitamins are classified as fat soluble and water soluble based on their solubility in lipid and water.
Lipid Soluble Vitamins: A, D, E and K
Characteristics of fat (lipid) soluble vitamins
- Soluble in organic compounds like oils, chloroform, benzene and ether.
- Stored in different organs (vitamin A in the liver and vitamin D in the bone and get released to their functional sites when needed.
- Insoluble in water, so they are utilised only if there is enough fat in the body
- Transported in the blood with a carrier protein.
- Deficiency does not develop following an acute shortage of the vitamins.
Water Soluble Vitamins: B and C
Characteristics of water soluble vitamins:
- Soluble in water.
- Absorbed directly from the intestine.
- Freely transported in the blood.
- Not stored; the extra amount beyond the body needs is excreted.
- Develop deficiency following acute shortage.
(Note: Fruits and vegetables are the best sources of vitamins).
Food Source and Functions of Vitamins
| Vitamins | Function | Food source |
|---|---|---|
| Vit. A | Normal vision; immunity epithelial cells function; normal development of teeth and bones. | Breast milk, tomatoes, cabbage, pumpkins, Mangoes, papaya, carrots, liver, kidney, egg , milk, butter, cheese, cream. |
| Vit. B -group | Metabolism of carbohydrates, proteins and fats, co-enzyme, normal nerve cell function. | Milk, egg yolk, liver, kidney and heart, whole grain cereals, meat, whole bread, fish, bananas. |
| Vit. C | Collagen formation, prevents gum bleeding, aiding wound healing, assisting absorption of iron for RBC production. | Fresh fruits (oranges, banana, mango, grapefruits, lemons, potatoes) and vegetables (cabbage, carrots, pepper, tomatoes), breast milk. |
| Vit. D | Needed for absorption of calcium from small intestines, calcification of the skeleton | Produced by the body by using ultraviolet light from the sun, eggs, butter, fish, fortified oils, fats and cereals. |
| Vit.E- It is a constituent of many | Normal growth and development; prevents oxidation of free radicals in the body. | Sencha, tea, sunflower oil, red pepper, cottonseed oil, wheat germ, rice bran oil, corn oil, margarine, fish |
| Multivitamins and mineral preparations | protects tissue against oxidation; promotes normal RBC formation; involved in reproduction. | liver |
| Vit. K | For blood clotting | Green leafy vegetables, fruits, cereals, meat, dairy products |
II. Minerals:
Minerals are inorganic chemical elements / substance/ that do not originate in animals or plants life but rather from the earth's crust. They are important in many biochemical and physiological processes necessary for optimum growth, development and health. They are essential structural components of body tissues.
Food Source and Functions of Minerals
| Minerals | Function | Food sources |
|---|---|---|
| Calcium | Bones and teeth rigidity and strength. | Milk, cheese and dairy products. Foods fortified with calcium, e.g. flour, cereals. eggs, fish, cabbage. |
| Iron | Hemoglobin formation | Meet and meet product, egg, bread, green leafy vegetables, pulses and fruits. |
| Iodin | Normal cellular metabolism | Iodized salt, sea vegetables, yoghurt, cows milk, egg and cheese, fish. |
| Zink | Normal growth and development, wound healing, immune function, protein synthesis. | Maize, fish, breast milk, meat, beans. |
| Fluorine | Keeps teeth strong | Water |
| Copper | For iron absorption & a variety of enzyme reaction, RBC formation. | Shellfish, liver, nuts, legumes and organ meat |