Vitamins and Minerals

A summary of the functions of some of the important vitamins and minerals in the body.

Source: Herald-Sun. Monday November 5, 2001.

What it does: Needed for healthy lungs, reproductive system, skin and linings of the digestive system. Also important for growth, good vision and fighting infection.

How it works: Used in the production of immune cells, which increases resistance to infection; keeps eyes moist. It helps fertility and keeps skin supple.

Good sources: Fish, egg yolks and liver. Carrots, sweet potatoes and mangoes contain beta carotene, which the body can covert into vitamin A.

Adult RDI: 750mg. Pregnant women should avoid supplements.

What it does: One of the vitamin B group, it reduces risk of spina bifida and possibly heart disease. It is also used in the formation of healthy blood.

How it works: Essential for development of spinal cord within three months of conception. May reduce homocycteine levels which can damage arteries.

Good sources: Fortified breakfast cereals and bread, liver, black-eyed beans, brussels spouts, peanuts, spinach, broccoli, chickpeas.

Adult RDI: 200mcg; 400mcg for women of child-bearing age to reduce risk of spina bifida.

What it does: Produces healthy blood, maintains the nervous system and controls growth in children. It also helps to control appetite.

How it works: Contributes to the production of red blood cells and is needed to create the fatty sheath around nerves, which allows the quick transmission of nerve impulses.

Good sources: Liver, red meat, game, fish, eggs, fortified breakfast cereals, fortified yeast extract, brewers yeast.

Adult RDI: 2mcg

What it does: Helps to repair muscles, balance sex hormones, keep the nerves in good condition and release energy into the body.

How it works: Works alongside enzymes influencing hundreds of processes in the body. Converts food energy into energy usable by cells.

Good sources: Wheatgerm, wheatbran, liver, cod, turkey, beef, bananas, brussels sprouts, cabbage, mangoes, avocados and potatoes.

Adult RDI: 1.6mg

What it does: Helps to heal wounds and fight free radicals that may lead to cancer and cataracts. Reduces the severity of colds and helps to fight stress.

How it works: Crucial for building the collagen 'cement' between cells in repairing broken skin, gums and damaged internal tissues. Helps the body absorb iron.

Good sources: Berries, citrus fruit and juices, papaya, guava, peppers, dark green vegetables.

Adult RDI: 40mg.

What it does: Essential for strong bones and teeth and for ensuring muscles work smoothly.

How it works: It promotes calcium and phosphorus absorption from the digestive system and aids the deposition of these minerals on to the bones.

Good sources: Fresh tuna, sardines, salmon, cheddar cheese, eggs, margarine.

Adult RDI: 10mcg.

What it does: Protects cells from attack by damaging free radicals which are linked to cancer. Keeps heart, circulation, skin and nervous system in good condition.

How it works: Cholesterol damaged by free radicals can build up on artery walls and case heart attacks and strokes. It's also vital for the optical nerves.

Good sources: Wheatgerm oil, sunflower oil, sunflower seeds, hazelnut, almonds, pinenuts, sweet potatoes, spinach, museli.

Adult RDI: 10mg

What it does: Essential for bloodclotting and making teeth and bones strong. It may also be involved in reducing heart disease.

How it works: Made in the body, Vitamin K is needed to produce proteins that help to use calcium in formation and maintenance of strong bones and teeth.

Good sources: Broccoli, brussels sprouts, green cabbage, yoghurt, alfalfa sprouts, egg yolk, kelp.

Adult RDI: 80mcg.

What it does: Builds and maintains strong bones and teeth. Also important for muscle contraction and blood clotting.

How it works: 99% of the body's calcium is found in the bones and teeth, where it is laid down on a protein matrix.

Good sources: Skimmed milk, cheddar cheese, sesame seeds, tahini, tofu, canned sardines with bones, dried figs, dark-green vegetables, baked beans.

Adult RDI: 800mg

What it does: Keeps blood in good condition, maintains the immune system and promotes good levels of energy and concentration.

How it works: Part of blood haemoglobin, which transports oxygen to cells. Poor iron balance reduced concentration and increases risk of infection.

Good sources: Red meat, oily fish, crab, clams, venison, fortified breakfast cereals, sesame seeds, dried apricots, dark-green leafy vegetables.

Adult RDI: 12mg.

What it does: Vital for healthy reproductive system and robust immune system. Helps heal wounds, acne and eczema. Important for male fertility and prostate health.

How it works: Needed for correct functioning of more than 70 enzymes. It is particularly important for formation and functioning of the cells of the immune system.

Good sources: Oysters, wheatgerm, calf liver, pumpkin seeds, beef, lamb, canned crab, pork, sardines, fortified breakfast cereals.

Adult RDI: 12mg.

Last Updated: November 9, 2001.