Food watchdog warns against high doses of vitamins and minerals

Many people could be damaging their health by taking vitamin and mineral supplements in doses that are too high, the UK's food watchdog, the Food Standards Agency, warned this week.

Most people in Britain do not need to take vitamins or dietary supplements because many foods are naturally high in vitamins or have been fortified with them, says the Food Standards Agency.

Adding regular vitamin pills to the amount obtained through a balanced diet can push people over the recommended daily level several times over, it has warned.

The agency's expert group on vitamins and minerals has spent four years looking at the evidence on the potential harmful effects of taking high doses of 34 vitamins and minerals that can be bought over the counter. It found enough evidence to suggest safe upper levels for eight of them and suggested guidance on 23. It also issued statements on three minerals.

Two supplements—namely b carotene and chromium—have the potential to cause cancer in some people, the group found. Smokers and those who have been exposed to asbestos should avoid b carotene, it advises. Chromium picolinate supplements may also cause cancer and should be avoided, although more research is needed.

More common vitamins have been linked with a range of problems. For example, vitamin C in large amounts can lead to stomach pain, diarrhoea, and flatulence and vitamin A can increase the risk of osteoporosis and fetal malformations in pregnancy.

As a result of the group's findings, the agency is considering whether to recommend that supplement manufacturers reduce the doses of their products and include warnings for some high dose supplements.

Professor John Krebs, chairman of the agency, said: “While in most cases you can get all the nutrients you need from a balanced diet, many people choose to take supplements. But taking some high dose supplements over a longer period of time could be harmful.

“We are using an extremely thorough independent expert review of scientific evidence on the sale of vitamins and minerals as the basis for new advice to help consumers make informed choices. In addition, the board of the Food Standards Agency will be considering what further action we would wish the supplements industry to take.”