VITAMINS

There are two categories of vitamins: those that are soluble in water and those that are soluble in fat. The water-soluble vitamins can be excreted in the urine, they are not particularly toxic, except at very high doses. Apart from vitamin B12, which is stored in the liver, try to eat food that contain water-soluble vitamins everyday. If you wish to take supplements, the B vitamins work together and need to be balanced. It is best to seek professional advice if you want to take supplements of single B vitamins or choose an over-the-counter multivitamin because the manufacturer usually balances doses of individual B vitamins.

Fat-soluble vitamins (vitamins A, D, E and K) are toxic at lower doses than water-soluble vitamins, but they are stored for longer in the body and do not have to be eaten everyday. If you wish to take supplements, it is best to take fat-soluble vitamins in only one preparation at any one time, and to follow the manufacturer's instructions carefully so that you do not take too much.

Vitamin A: Retinol and Beta-Carotene
Needed for: good vision, especially at night; healthy skin and mucuous membranes; a healthy immune system.
Good sources: milk, eggs, liver, butter, enriched margarine and fish liver oil. All these contain pre-formed vitamin A (retinol). In addition, vitamin A is made in the body, from beta-carotene, found in red and yellow vegetables and fruit, such as sweet potatoes, spinach, sweet peppers, carrots, tomatoes and apricots.
Cautions: when eaten or supplemented in large amounts as vitamin A. Do not exceed 9,000mcg (micrograms) a day for men and 7,500mcg a day for women. There are no known toxic side effects from beta-carotene.

Vitamin B1: Thiamine
Needed for: maintaining energy levels: a healthy nervous system.
Good sources: milk, offal, whole grains, fortified breakfast cereals, pulses, nuts, fruit and seeds.
Can be lost: when food is boiled or steamed. Absorption in the intestine is reduced when alcohol is also present.
Cautions: can be toxic in high doses.

Vitamin B2: Riboflavin
Needed for: good vision: healthy hair, skin and nails: maintaining energy levels: combating stress.
Good sources: milk, cheese, yoghurt, eggs, beef, fish, mushrooms and fortified breakfast cereals.
Can be lost: when the food containing riboflavin is exposed to light. Such food should be stored in the dark.

A healthy diet contains 2-4 portion of fruit and 3-5 portions of vegetables each day.

Vitamin B3: Niacin, Niacinamide, Nicotinic acid, Nicotinositol hexaniacinate
Needed for: energy: brain function: healthy skin: controlling cholesterol levels.
Good soources: beef, pork, chicken, white fish, wholemeal bread, eggs, baked beans, peas and fortified breakfast cereals.
Can be lost: up to 90% is removed when whole grains are milled.
Cautions: can cause blood pressure to fall. Consult your doctor before taking supplements, if you have any medical condition.

Vitamin B5: Pantothenic acid
Needed for: the release of energy from food.
Good sources: pulses, meat,eggs, fish, wheat germ and many other foods. Dietary deficiency has not been reported.
Can be lost: during cooking and from grains during milling.

Vitamin B6: Pyridoxine
Needed for: new red blood cells: a healthy immune system.
Good sources: meat, fish, poultry, eggs, whole cereals, peas, avocados and bananas.
Can be lost: when food is exposed to sunlight, during cooking, milling of grains.
Cautions: can be toxic in high doses.

Vitamin B12: Cobalamin
Needed for: new blood cells: protection of nerv cells: to enable all cells to function efficiently.
Good sources: milk, cheese, egges, meat, fish, fortified breakfast cereals and yeast extract.

Folic acid or Folate
Needed for: red blood cell productions: healthy skin, hair and nerves.
Good sources: green leafy vegetables, offal, yeast extract and fortified breakfast cereals.
Can be lost: when food is exposed to light and heat (even room temperature).
Cautions: can be toxic in high doses. Consult your doctor before taking supplements if you take medication for epilepsy or have a family history of pernicious anaemia.

Biotin
Needed for: healthy skin and nails: the absorption of vitamin c.
Good sources: fruit, nuts, sardines and eggs. Ample amounts are normally made in the intestine.

Vitamin C: Ascorbic Acid
Needed for: healthy connective tissue and immune system.
Good sources: kiwi fruits, mangoes, cauliflowers and cabbage.
Can be lost: during cooking.
Cautions: reduce the dose if you develop diarrhoea when taking a supplement. Also, consult your doctor before taking supplements if you or a relative have had kidney stones.

Vitamin D
Needed for: healthy bones: balancing minerals in the body.
Good sources: herring, kippers, salmon, sardines, fortified margarine and breakfast cereals, cod and halibut liver oil.
Cautions: toxic in large amounts, although the threshold for toxicity is unknown. Consult your doctor before taking a supplement if you have sarcoidosis.

Vitamin E: Tocopherol
Needed for: neutralizing free radicals; protecting the fats in cell membranes.
Good sources: vegetable oil, nuts, seeds and wheat germ.
Can be lost: during food processing, such as milling, cooking and freezing; or when food is stored, especially if exposed to the air - for example unshelled nuts.
Cautions: consult your doctor before taking a supplement if you have high blood pressure or taking anticoagulant medication.

Vitamin K: Phylloquinone, Menadione
Needed for: blood clotting, helping to build strong bones.
Good sources: many vegetables, including spinach, cabbage, cauliflower and peas.
Cautions: consult your doctor before taking a supplement if you are being prescribed anticoagulant medication. Synthetic vitamin K (Menadione) can be toxic and if a supplement is being taken do not exceed the recommended daily intake.

Although vitamins and minerals are only needed in small quantities, they are essential for health.