The Safety of Vitamin and Mineral Supplements – Dr Alan Stewart
In the light of the concern about the restrictions which are to be imposed on over the counter sales of high dose vitamins and minerals Dr Alan Stewart looks at the Expert Group on Vitamins and Minerals’ report on ‘Safe Upper Levels For Vitamins and Minerals’.
In May this year the Expert Group on Vitamins and Minerals, an independent expert advisory committee set up by the Food Standards Agency, reviewed the safe levels of intakes for vitamins and minerals in food supplements and fortified foods. Their report Upper Safety Levels For Vitamins and Minerals, is over 350 pages long, is very detailed and well referenced and contains a lot of information on the toxicity of nutrients in animals and humans. The committee has set limits for many vitamins and minerals in nutritional supplements that mean a change in formulation of many products, or their removal from sale.
• Beta-carotene 7,000ug / day
Set Upper levels (SULs) have been set for eight vitamins and Guidance Levels(GLs) for twenty-two others. Whilst there is little issue for most of the vitamins and minerals there is a strong and justifiable view that the levels set for Vitamin B6 and Vitamin C are unduly cautious. These levels, it should be stressed, apply to supplements that are being bought over the counter and not on the recommendation of a doctor who, in theory, is in a position to assess the specific needs of the individual.
Consequences for those Taking Supplements
For most people taking simple supplement regimes including most one-a-day preparations, calcium and modest amounts of other minerals and vitamins no action is necessary. For those taking strong multivitamins or high dose Vitamin B or C, or for any of the groups below, occasional review by your doctor or an experienced nutritional therapist is advisable.
Those aged 65 years and over should be kept under regular review because of changing needs, the possibility of new medical problems occurring which might influence the risk of toxic effects, and drug-nutrient interactions.
Those with chronic liver, kidney or blood disorders and anyone with an uncertain medical diagnosis needs regular review. Children with growth problems or any chronic illness also need regular review.
As a rule women in this situation should not take anything other than folic acid or an appropriate multivitamin/mineral supplement for pregnancy without professional advice, although many additional supplements are likely to be safe in low doses and may be needed. Women seeking to become pregnant and taking supplements should also seek professional advice and switch to an appropriate pre-pregnancy supplement. High intakes of supplements in breastfeeding women could well result in an excessive intake for the infant.
Drug Nutrient Interactions
There are many possible drug/supplement interactions and whilst they were not considered in detail by the Expert Group it is relevant to mention some.
Those with pre-existing medical problems (see table below) also need careful regular review and should not take supplements containing relevant nutrients without professional advice. Most of these situations are relatively rare but virtually all doctors will have come across them at some time.
The vast majority of supplements are indeed safe but there are concerns about some high dose preparations, about the prolonged use of some supplements in both the healthy population and those with certain illnesses or taking certain drugs, and about the use of supplements in people in particular situations such as pregnancy.
First published in 2003
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