She wakes up in the morning and takes a stress-relief multi and a vitamin C super-dose before going to the gym. He whizzes up a "vitamin" shake and races off to work. Mid-morning she downs another handful of vitamins - these to boost her hormones for an intended pregnancy - and he substitutes a creatine protein drink for a sit down lunch and takes off for a sprint around the park.

With the absence of sit-down time for lunch, worries about weight, and the promise of enhanced vitality, twenty to forty-five year olds are increasingly turning to supplements as meal substitutes, further fuelling an industry that is already in top gear.

According to figures compiled by Adelaide University's associate professor Alistair MacLennan, honorary editor of "Current Therapeutics", a monthly publication for Australian GPs, we now spend over $2 billion a year on alternative health services and products - double the amount seven years ago and twice as much as our out of pocket expenses on all conventional medical treatments.

We live in an era of the "quick fix", with many of us feeling we need the extra boost vitamins and supplements claim to offer. But many of us never stop to think about the potential harm of overuse and indiscriminant dosage. The Institute of Food Technologists* in the United States estimates that almost half the entire adult population regularly consume dietary supplements, yet they warn that "relatively little data exists on the physiological effects of many available products".

Are They Safe?

Vitamins and minerals are essential nutrients that the body does not manufacture. Traditionally sourced from food intake, they are necessary for many vital functions in the body and important for providing good health.

The new wave of vitamin dependency rises partly because modern diets do not always represent the balanced nutrient-rich food choices. Consider a city street during lunchtime - it is far more common to see people eating nutrient-poor French fries than it is to find anyone munching on a carrot.

And it is increasingly common to find workers skipping lunch to meet a deadline or go for a run. These people often mistakenly believe their supplement intake is providing for their needs; but only food provides the calories necessary for daily living whereas vitamins do not.

Added to this inappropriate substitution is a growing suspicion in the medical community of the danger associated with excessive vitamin use. Unlike drugs and additives, which must undergo rigorous scientific testing for safety and efficacy, supplements have little or no requirements prior to marketing and sales.

"The industry is hardly regulated at all," says associate professor John Eden, director of the Natural Therapies Unit at Randwick Royal Hospital for Women. "So there are big issues with what we take for granted in the pharmaceutical industry - things like quality control, how much active product is actually in a dose, proof of efficacy and safety."

In a recent study* of more than two hundred patients with Parkinson's disease, 40 percent admitted to using at least one type of alternative therapy including vitamins and herbs, and over half of the patients failed to inform their physicians about their use.

"This is concerning," says Stephen Reich, M.D., co-author of the study and associate professor of neurology at John Hopkins. "While the public generally assumes vitamins and herbs are safe, a rapidly growing number of studies show they can have potentially harmful effects and interactions with other drugs."

If you are a "one-a-day" vitamin person, there is no cause for alarm and no reason to discontinue your daily dose. For the most part vitamin and mineral supplements are safe to take. But it is important to understand that the cycle of substitution that replaces real food with supplements is potentially harmful to health and balanced living. Misuse and overuse of supplements, particularly in the case of vitamins A, D, E, B-6, niacin and iron can eventually be dangerous to your health, even toxic.

Dr Eden, who undertakes science-based studies into supplements at the Natural Therapies Unit, advocates a "middle way". Become informed about the potential benefits and dangers of whatever you put into your body. Resume eating "real" food. And remember to keep your doctor informed about your supplement intake.

Below is a list of vitamins and everyday food sources.

Vitamin A

(Retinol and Beta-Carotene), promotes health of the eyes, skin and inner linings: increases immunity to infection.

Best sources: carrots, winter squash and other yellow or orange vegetables; broccoli, kale and other dark green leafy vegetables and nori seaweed.

Thiamine

(Vitamin B1), essential to carbohydrate metabolism, nervous system function, lactation, fertility; protects against beriberi.

Best sources: whole grains, beans, vegetables, seeds and nuts, and sea vegetables.

Riboflavin

(Vitamin B2), essential to carbohydrate and protein metabolism; protects eyes, skin, and mucous membranes; facilitates antibody and red-blood cell formation.

Best sources: whole grains, beans, leafy green vegetables and sea vegetables.

Vitamin B6 (Pyridoxine), assists in carbohydrate and protein metabolism.

Best sources: whole grains, beans, cabbage, and nuts.

Vitamin B12

(Cobalamin), assists in red-blood cell formation and maintenance of nerve tissues; protects against pernicious anaemia.

Best sources: fish and seafood.

Niacin

Contributes to the health of the tongue, skin, and other organs and tissues; aids in fat synthesis, carbohydrate utilisation, and tissue respiration.

Best sources: whole grains; beans; vegetables, especially shiitake mushrooms and green peas; sea vegetables, seeds and nuts.

Folacin

Aids in red-blood cell formation.

Best sources: leafy green vegetables and sea vegetables.

Vitamin C

(Ascorbic Acid), assists in formation of connective tissue; contributes to healing of wounds and broken bones; aids in red-blood cell formation; protects against capillary wall ruptures, bruising and scurvy; linked with decreased risk of gastric cancer.

Best sources: broccoli, mustard greens, kale, and other leafy green vegetables; strawberries, cantaloupe, and other fresh, seasonal, temperate-climate fruits.

Vitamin D

(Calciferol) promotes calcium absorption essential in formation of bones and teeth; protects against rickets.

Best sources: sunlight, fish liver oils.

Vitamin E

(Tocopherol), prevents oxidation of unsaturated fatty acids, Vitamins A and C, and other substances in the body; lowers serum cholesterol and facilitates blood circulation; strengthens fertility and potency; inhibits tumour formation.

Best sources: green leafy vegetables, unrefined vegetable-quality oils, whole grains, and beans.

Vitamin K

Contributes to normal blood clotting.

Best sources: leafy green vegetables.