The Pharmaceutical Journal
Vol 269 No 7214 p315
7 September 2002

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New guidance sets upper safety limits for vitamin and mineral supplements

A draft document proposing maximum intake levels for 34 vitamins and minerals was sent out for consultation last week. Monika Polak (on the staff of The Journal) looks at its implications

Related websites
Food Standards Agency (www.foodstandards.gov.uk)

Vitamin and mineral supplements have recently been making newspaper headlines, as controls on their sale and use are beginning to tighten. The latest development is the publication of a draft document from a government advisory group, advising on safe maximum levels of vitamin and mineral consumption.

The Expert Group on Vitamins and Minerals (EVM) was set up in 1997 to advise the Food Standards Agency on safe levels for vitamins and minerals and includes representatives from the medical and scientific community, consumer groups and industry. It has spent the past four years scrutinising nutritional and toxicological evidence, from both human and animal studies, and has done detailed risk assessments based on this data for 34 specific vitamins and minerals. The results of these labours were published last week as a draft report that was sent out for consultation among more than 1,100 interested parties including retailers and industry, the National Health Service, voluntary organisations and consumer groups.

The EVM's recommendations, which are only applicable to vitamin and mineral food supplements sold under United Kingdom food legislation and not those sold as prescription or over-the-counter medicines, have been broadly welcomed. Chief scientist at the Royal Pharmaceutical Society of Great Britain, Tony Moffat, says: "By and large in the UK, nearly everyone gets sufficient vitamins and minerals from their normal diet, but some at-risk groups may benefit from supplements. We welcome setting minimum daily requirements, but there should also be maximum levels — people should be warned that if they take some super-strength vitamins, it could do them harm."

He adds that pharmacists should always provide advice on vitamin supplements and that people should be reminded that eating vitamin-fortified food could increase cumulative vitamin intake above levels that are safe.

Dr Derek Shrimpton is a consultant in nutrition and food science and an adviser for the Health Supplements Information Service, an independent group of academics that consults with the food supplements industry. He agrees that setting maximum safe levels is necessary, but says the EVM report simply endorses what industry has already been doing for a number of years. He believes the new safe intake levels advised by the EVM will make little or no difference to the vitamin and mineral supplements that are currently on sale in pharmacies. "It's very helpful to have an independent committee coming to a similar conclusion. The fact that the majority of the upper levels have remained unchanged or been relaxed is a testament to the existing limits already in place and that they are safe and already working," he adds.

According to Dr Shrimpton, approximately three-quarters of supplements used are multivitamins and these are produced in line with current recommended daily allowable levels. The next most popular supplements are antioxidants which, he says, are also well below the new safe limits recommended by the EVM.

However, in its report the EVM lists vitamins and minerals for which intake may exceed the proposed safe upper levels (see Table 1). It also lists supplements that may be taken at doses above those declared as safe by the EVM (ie, the dose that would not be expected to produce adverse effects).

The EVM criticises the lack of available safety data on vitamins and minerals: "There is a particular lack of reasonable-sized, well-designed comparative human studies of significant duration at different levels of intake. Moreover, there has rarely been adequate consideration of potentially vulnerable population subgroups such as children or older people," it says.

As a result, safe upper levels of consumption have only been set for nine of the vitamins and minerals investigated — vitamin B6 and beta-carotene, vitamin E, boron, copper, nickel, selenium, zinc and silicon. Guidance on safe levels, not to be confused with safe upper levels, was suggested for a further 22, and statements were issued for the remaining three — germanium, vanadium and sodium chloride — because the data were inadequate to inform either safe upper limits or guidance. These three, the report says, are not suitable for use in food supplements even though they are still used in some instances. Specifically it notes that vanadium supplements aimed at body builders and dietary supplements containing germanium, which were voluntarily withdrawn in the UK, are available over the internet.

The report also draws attention to "overage", where a product is manufactured to contain a higher vitamin or mineral content than stated on the label. This happens particularly with fat-soluble vitamins; for example, levels of vitamin A found in single supplements can range between 22502400µg, whereas the EVM recommends that daily intake be no more than 1500µg per day. Dr Shrimpton, who is also an EVM observer, explains: "Vitamin A is labile, so you have to over-formulate to begin with. Risk managers have to take into account the realities of the manufacturing process, and the efficacy of labelling, and whether current labelling is adequate."

The labelling issue has been addressed in a recent EC directive (2002/46/EC) aimed at harmonising legislation on food supplements across member countries, which will be implemented and become UK law by 31 July 2003. This directive also states which vitamins and minerals, and which sources of them, should be used in supplements, and provides for the setting of maximum levels of vitamins and minerals, once these have been decided on. It is hoped that the FSA's final advice on safe vitamin and mineral levels, following the current consultation period, will be incorporated into any recommendations made by the EC's Scientific Committee on Food, which is now undertaking a similar evaluation.

The EVM draft report is available on the FSA website, and comments should be submitted before 21 November 2002.