How safe are supplements?

The benefits of high-dose nutrients are being called into question. By Emma Haughton

If you felt a bit peaky 20 years ago, all you'd find in Boots would be a bottle of tonic. Today the shelves of chemists and health food stores are crammed with a bewildering array of "super supplements": high-dose vitamins, minerals, enzymes and essential fatty acids, all claiming to promote vitality and good health.

Take your pick from antioxidants like A, C and E, reputed to ward off cancer and heart disease, B-vitamin complexes for more energy, betacarotene to fight off free radicals, calcium for strong bones, iron to pump up those red blood cells, or selenium to bolster bodily defences. Not to mention those mysterious products with unpronounceable names: lactobacillus acidophilus for healthy guts, ginkgo biloba for good circulation, chlorella for bone strength and development, or lecithin to reduce cholesterol.

But the days when UK consumers can spend pounds 250m a year on dietary supplements may be numbered, according to a new pressure group, Consumers for Health Choice. Next week this international alliance of more than 30 organisations, companies and support groups will converge on Westminster to protest against European proposals that may sweep many of these products off our shelves.

Back in 1992, only intense lobbying by UK consumers and manufacturers prevented the European Commission from ruling that supplements containing more than 1.5 times the recommended daily allowance (RDA, the official level needed to prevent obvious deficiency diseases like scurvy and beriberi) should be classified as medicines; higher doses would be available only through pharmacies or under prescription, which is the situation in most of Europe.

Now pressure from the French, Spanish and Greek governments makes it likely the proposals will be resurrected this autumn. If endorsed, higher dose nutrients may become subject to expensive drug licensing procedures, typically costing pounds 100,000 per product. Manufacturers say such costs will force them to abandon 95 per cent of their products, while the prices of those remaining will rocket.

These proposals are bringing to a head the fierce debate between nutritional therapists, who believe that higher dose supplements are invaluable in preventing and curing many ailments and diseases, and doctors with more orthodox views who insist that vitamin pills, particularly the high-dose variety, are at best useless, at worst downright dangerous.

A London Food Commission survey of 18 popular brands of vitamins has already cast doubt over their effectiveness. As nine failed to dissolve satisfactorily within 30 minutes, it concluded that the body would simply excrete them, although nutritionists would argue that some formulations are more easily assimilated than others.

But Professor John Garrow, editor of the European Journal of Clinical Nutrition, says supplements could be worse than just a waste of money. Many vitamins and minerals work as a team, so large doses can upset the body's delicate balance.

"You can cause anaemia, for instance, by giving large doses of zinc, which impairs the absorption of the copper required in blood formation," he says. "There are an enormous number of knock-on effects with minerals reacting with one another."

Dosing yourself up with large quantities of vitamins and minerals can do you little good, agrees Dr Colin Waine, chair of the Royal College of General Practitioners' nutrition working party. "After all, you don't leave the tap on when you've drunk water. The first priority is to get people eating a healthy diet to provide nutrient requirements without resorting to supplements."

But do most of us eat a healthy and balanced diet? The Institute for Optimal Nutrition, an educational trust which researches and promotes nutritional issues, points out that five reports in the past five years have all reached the same conclusion - at least half the British population have an intake of vitamins and minerals well below the levels designed to prevent deficiency.

The Institute is also concerned about the quality of our food. "Think back to our grandparents who shopped daily or ate fresh produce from the garden," says Diane Mills, one of its nutritionists. "Now we go to the supermarket once a week and leave food wilting in the bottom of the fridge - by the time we eat it, it's dead." Poor food is compounded by problems in absorbing what we eat. "Look at the huge sales of indigestion tablets and it's obvious that a lot of people are not digesting properly."

The result, nutritionists believe, is a range of health problems caused by long-term nutrient deficiencies: constant tiredness, skin problems, headaches, poor resistance to infection, hormonal problems and irritable bowel syndrome, all of which could be remedied by correct supplementation. But many nutritionists go even further and use high-dose therapy to treat a diverse range of conditions.

One study, for instance, showed that 450mg magnesium supplements significantly reduced seizures in epileptic children. In Canada a psychiatrist who conducted trials on 4,000 patients found that large amounts of vitamin B3 helped alleviate the symptoms of schizophrenia. Devotees believe that nutritional therapy is also effective in treating infertility, ME (chronic fatigue syndrome), allergies and asthma.

Linda Lazarides, a nutritional therapist and founder of CHC, also says recommended levels are often inadequate for those with poor absorption, infection, metabolic abnormalities or genetic differences. She also believes symptoms resulting from nutritional deficiencies are usually relieved much more rapidly with high doses of vitamins than with small amounts.

"It's a bit like trying to revive a commercial business that's been slowly going bankrupt. You can put some cash back into it to keep things from getting worse, but it's not going to thrive on its own again until you inject a bit of capital."

Recent studies seem to support her views. One, for instance, found that people with low intakes of beta-carotene, an antioxidant which is converted into vitamin A in the body, had a 30-220 per cent higher risk of developing lung cancer than those with a higher intake. But while the majority of doctors now accept the important role of antioxidant vitamins like A, C and E in preventing cancer and heart disease, most still recommend that we get our daily fix from food rather than pills.

Garrow stresses quite bluntly the danger of assuming that you can't have too much of a good thing.

"One study in Finland gave vitamins A and E to 40-year-old male smokers to see if they affected their chance of getting a tumour. They did - those on vitamin A actually developed more tumours. People take these supplements to be on the safe side, but they may not be on the safest side."

In its defence the pro-vitamin lobby points out that supplements have an excellent safety record. In eight years the National Poisons Unit received just 42 reports of adverse reactions to dietary supplements, compared to an annual toll of 10,000 hospital admissions from reactions to prescribed drugs. Many of the supplement cases involved children accidentally swallowing iron tablets prescribed by doctors for pregnant mothers.

It may be wise to err on the side of caution, but ever since research uncovered the ability of folic acid to prevent spina bifida in developing babies, the government has thrown it to the wind. Every woman embarking on a pregnancy is now advised to take a daily supplement of 400mcg of folic acid. And don't bother thinking you could get that in your diet: "It would be pretty difficult to munch your way through that much broccoli," says Ursula Arens, senior nutritional scientist at the government-backed British Nutrition Foundation.

Folic acid aside, those who oppose the wholesale consumption of higher dose supplements argue that if vitamins really are that effective, they should be treated like drugs.

"There are products on the market containing vitamins A, C, E and selenium which tell you they enhance your defences against cancer and heart disease," says Garrow. "That is a medical claim and so it is perfectly reasonable they should undergo the same screening process as conventional drugs."

This means they would only be available on prescription - and why put supplements under the control of doctors, argue the nutritional therapists, when many, by their own admission, are poorly trained in nutrition and dietetics?

Meanwhile, a government review of supplements to assess how they should be regulated has come down in favour of a "top down" approach. "You look across the data for any hint of an adverse effect and then build in a tenfold safety margin to get the maximum dose," says Arens, who believes the EC proposals are too restrictive.

"If we limit supplements to RDAs, you'll need to see your doctor to get anything higher. Chances are you won't bother, or if you did your doctor would tell you to stop smoking or eat more fruit. It will clearly be a hurdle that dramatically reduces people's individual choice as to what could improve their health."

'Nothing in orthodox medicine could help'

Carolyn Gibbs, 46, became ill in 1987 and was diagnosed as having myalgic encephalomylitis (ME) in 1988. She takes a total of 11 pills a day - at a cost of about pounds 55 a month.

"For a long time I didn't know what was wrong with me. I felt incredibly fragile, tired to the point of complete exhaustion, my legs ached, I was very shaky and I had very poor concentration. I was functioning at such a low level I felt like an amoeba. My life was completely turned upside down. By the time I was finally diagnosed ,I was bedridden and could hardly even roll over.

"I'd read that vitamin therapy could help and did try taking some vitamins but without success. It was too haphazard because I didn't know which ones were needed, so three years ago I approached a nutritional therapist.

"She started me off on a herbal preparation to regenerate my liver, which is often sluggish in ME suffers. She also thought I had a yeast infection so I took extract of coconut and a sodium compound, both of which have an antifungal action.

"For the past month I've taken extra vitamin E which my therapist recently found out plays a large part in oxygenating your muscles. I've already noticed I'm a lot less achey and can stand and walk around for longer.

"On top of that I take separate multivitamin and mineral tablets for a background dosage of everything. People with ME are like leaky buckets: because we don't absorb nutrients properly we need to be kept topped up. I take supplements of all the B vitamins, very important in energy production, and of reduced glutathione, an antioxidant.

"I also take GLA (gamolenic acid) which boosts brain activity, magnesium, which is also good for muscles and energy production, and taurine, an amino acid. Then there's a digestive aid which includes acidophilus to help gut absorption.

"From the beginning there's been a slow but definite improvement. Overall it's made an enormous difference. If I miss the supplements for a week or so I really do feel worse. There was nothing in orthodox medicine to help me at all."

WHICH PILLS DO WHAT?

Vitamin A, for healthy eyes and skin. High doses may cause birth defects: pregnant women are advised not to eat liver or take supplements.

B vitamins release energy from food; B 12 supplements are advised for vegans. But very high doses of B1 may cause headaches, irritability, insomnia and dermatitis; high doses of B3 may aggravate stomach ulcers and diabetes; and high doses of B6 may promote nerve damage.

Vitamin C for healthy tissue and fighting infections. Studies have found a diet rich in vitamin C is linked to lower mortality rates and may protect against lung disease. There is no proof that high doses can prevent colds, but they can cause diarrhoea and promote kidney stones. The body may become dependent on large doses of vitamin C - cutting down suddenly may produce symptoms of deficiency.

Vitamin D for strong bones and teeth. More may be needed by children who don't receive much sunlight in winter.

Vitamin E for healthy blood. Studies have linked higher doses to a reduced risk of heart attacks and cancer.

Iron for red blood cell development. At least 6 per cent of British women get less than the RDA from their diets, and heavy periods mean it can be difficult to replace through food alone. But inorganic iron compounds may cause diarrhoea or constipation.

Zinc for enzyme production. Very high doses may produce nausea, vomiting and fever, as well as copper deficiency and anaemia.

Multivitamin and mineral compounds for general well-being.