Vitamins should not be trifled with - they are active biochemicals best eaten in food Vitamins are no longer considered a harmless daily insurance policy and should only be taken under expert advice. Claire O'Connellreports
The actress Hilary Swank must surely rattle when she walks. According to recent media reports, the PS I Love Youstar swallows up to 45 food supplements a day, and uses injections of vitamin B12 to improve her energy levels.
While many would baulk at taking such elaborate cocktails, plenty of Irish people blithely pop a daily vitamin pill as insurance against gaps in their diet. But experts now believe that vitamins should not be trifled with - they are active biochemicals with potentially profound effects on health, and they are best eaten in foods, not supplements.
"Taking vitamins and minerals in concentrated form is very different from taking them in their naturally occurring state in foods," says Dr Mary Flynn, chief specialist in public health nutrition with the Food Safety Authority of Ireland (FSAI). "With the exception of vitamin A, it is impossible to overdose on vitamins and minerals in their natural food form. But once you take them out of their natural food form they are much more easily absorbed in the body. All the factors in the matrix of the food they live in normally have been cleaved off and they will go into the body much quicker."
That's why she believes we need to change our mindset about vitamins being a harmless daily insurance policy and start viewing them as drugs of sorts, and using them only when required.
"The FSAI is far from being against supplements and recognises that they are necessary to ensure optimum health of the population. But they are biochemically active, they are not something you throw around like confetti at a wedding," she says.
Flynn also believes that by taking high-dose supplements people could be at best wasting their money and making expensive urine, and at worst they could be dicing with their health.
"Nutrients don't act in isolation. If you take a high dose of something you will need to metabolise the excess and that can often deplete you in something else - for example, if you take calcium supplements you can inhibit your iron and zinc absorption," she says, adding that certain vitamins can interact with medications too.
However, the FSAI promotes supplementation where needed, adds Flynn, citing two of the agency's reports last year. One backs up the advice for women who could become pregnant to take 400 micrograms of the B vitamin folic acid daily, which has been shown to reduce the incidence of neural tube defects, such as spina bifida, in the developing baby.
But folic acid also demonstrates that with vitamins, when it comes to a good thing, more is not necessarily better, notes Flynn. "If you take very high amounts of folic acid, 5mg or more in the long term, the incidence of vitamin B12 deficiency is higher and you can mask it, and you can go on to develop irreversible neurological problems."
The FSAI also recommends vitamin D supplements for all infants, a step taken when children started showing up in Dublin hospitals with the bone condition rickets, a symptom of severe vitamin D deficiency.
Unlike other vitamins, the body can make vitamin D itself using a process triggered by sunlight. But in winter, the quality of sunlight that reaches Ireland is not sufficient for us to make what we need, explains Flynn.
"Between September and March you are not going to get any vitamin D synthesis, even if you get a sunny day. And we have lots of evidence from Ireland where in the winter people are deficient - children, middle-aged people, women of childbearing age," she says, noting that babies born to mothers deficient in vitamin D will inherit a low initial store of the vitamin themselves, hence the recommendation for single-vitamin supplements.
But what about the rest of us who might smugly swallow a multi-vitamin with breakfast and think we are covered? "People would be infinitely better off to be focusing on their diet instead," says Flynn. "We have the biggest crisis in terms of obesity - do we need concentrated forms of more nutrition? No, quite the opposite, we need to be bulking ourselves up, trying to get our vitamins in a low-calorie way that fills us up and stops us from eating so much chocolate.
"But if you are run down then maybe take a multi-vitamin and mineral for a limited time and look at your diet. And make sure the supplement provides the recommended daily allowance for your age and sex. The RDA covers the needs of over 97.5 per cent of the population. It's the optimal level. Exceeding this level brings no benefit but can cause harm. So why would you go higher?"
Diet is certainly the best source of vitamins and minerals, and supplements should be used only as a short-term support, agrees Bray-based nutritional therapist Grace Kinirons. But she believes the RDA is a blunt guide that takes broad swathes of the population into account, and that it could stop people benefiting from vitamin supplements their individual situation might need.
"Everybody is biochemically different," she says. "The new science coming out from the genome is backing that up, and we can't make broad generalisations. Also people with very stressed lifestyles, who eat a lot of processed foods or drink a lot of alcohol do have a higher requirement for certain vitamins and minerals.
"I think there is a need for supplements above the RDA in certain circumstances. But it would all be done on an individual level and I would not be in favour of people rushing into the health food shop and taking 5,000mg of vitamin C because they have read about it. It's much more complex than that. People need to seek expert advice on their personalised needs."