Vitamins are essential to being alive. Our ancestors have been guzzling them since before they had spines, and they’re a key element in a number of chemical reactions that support our immune system, metabolism, and yes, our shiny, shiny hair. If we deprive ourselves of them, we’re subject to rickets, scurvy and all sorts of awfulness.

Certainly, vitamin supplements have done a lot of good. In third-world countries vitamin A deficiency can cause a whole range of eye diseases – which can be immediately repaired by a small supplementation in their diet.

Studies looking into populations that live longer and were generally healthier found they had high concentrations of vitamins A, C and E in their blood. But here’s the important bit: they got those vitamins by eating lots of fruit and veg.

This perception that we need vitamins supplements is a naive, drug-discovery approach.

Dr Trent Watson, a representative of the Dieticians Association of Australia, says just because people who eat a boatload of fruit get more vitamins, but getting the vitamins without the fruit does not mean they will be just as healthy.

“What we’ve got to be careful of is not getting correlation mixed up with causation,” he advises. “There’s a correlation between high fruit and veg (intake) and health. But then, that was extrapolated by supplement companies saying these are obviously markers within these fruit and veg that provide these benefits, so we’ll just isolate those and supplement them.”

Dr Watson is adamant there’s no substitute for eating well. “The bottom line is that you can get all your essential vitamins from the food you consume.” he says. “I think, in the wash-up, this perception that we need vitamins supplements is a naive, drug-discovery approach.”

What about those time-honoured remedies – like fighting a cold with vitamin C? “There’s no evidence to support that Vitamin C is protective against us getting a cold, or reducing the duration with which you have it,” he says.

How about conquering your hangover with a fizzy vitamin B? “As a consequence of drinking a flavoured water that happens to have B vitamins in it, then maybe you’ll reduce dehydration. But B group vitamins don’t have any effect.”

And Dr Watson is hardly alone in suggesting you might as well flush your B-group vitamins as eat it. “Don’t waste your money” read a recent editorial by the Annals of Internal Medicine.

“The message is simple. Most supplements do not prevent chronic disease or death, their use is not justified, and they should be avoided.”

The scathing editorial preceded the findings from two studies that suggested that 6000 doctors over 65 who ate a daily multivitamin for ten years showed no improvement in retaining cognitive function than those who ate a placebo. Another study of 294,718 people in 2013 found that supplements made no impact on preventing cardiovascular disease.

“What you’re seeing is the marketing machine,” says Dr Watson. “They’re almost creating this worry through marketing to the general population, saying, ‘You need this stuff because food doesn’t have the vitamins and minerals.’ That’s not the case.”

Consumer watchdog Choice agrees.

“Marketing messages, often backed up by high profile sporting celebrities, give the impression that in order to be fit and healthy, we all need multivitamins,” says Choice spokesperson, Ingrid Just. “If you have a healthy diet and you’re not a person with specific nutritional requirements, there’s a good chance you’re wasting your money.”

If you have a healthy diet and you’re not a person with specific nutritional requirements, there’s a good chance you’re wasting your money.

While it’s galling that vitamin supplements actually may be totally useless, what’s more worrying is that there’s increasing evidence that in some cases, they can actually be harmful.

“‘Some is good, more is better,’ is not the case with this situation,” explains Dr Watson. “In fact, the law of toxicology says that anything, in the right dose, is toxic.”

Recent research has come up with some troubling findings. According to a New York Times article, a 2004 study found that taking vitamins A, C, E, beta carotene and selenium to prevent intestinal cancers increased mortality. Another found that in 19 trials of nearly 136,000 people eating vitamin E supplements increased mortality. Another discovered that vitamin E in high doses can lead to an increased incidence of cardiovascular disease. Yet another found that in 19 trials of covering 136,000 people, supplemental vitamin E increased mortality. A study in the 1990s into the effects of supplementing vitamin E and beta carotene in smokers had to be stopped because it was leading to increased instances of lung cancer.

“In medicine, our first course as practitioners is first to do no harm. Now, I think what’s happening here is that that’s not the case in some of these situations,” says Dr Watson.

Needless to say, Dr Watson doesn’t take his daily multi-group.

Of course, there are a number of perfectly legitimate reasons to supplement one’s diet – if you actually have a deficiency. But, surprise, surprise, wandering into the supermarket and buying armfuls of Health™ probably won’t work.

For real advice on getting your vitamin intake right, see a dietician or your local GP.