If you take a daily vitamin and mineral supplement, you may want to stock up before August 1. For after that date, the shelves of your local health food shop could be decidedly bare as tablets containing selenium yeast, boron, chromium picolinate and a further 300 nutrients are withdrawn from sale.

　　The European Food Supplements Directive, which comes into force at midnight on July 31, outlaws products containing ingredients not on its "positive list" of 140 permitted substances. An estimated 5,000 supplements will be affected, excluded from the positive list because they have not been assessed by the EU, even though under the UK Food Safety Act they are considered safe products (it is illegal to sell food that is unsafe).

　　The directive has two stages. The first, which comes into force on August 1, is concerned with the ingredients in supplements; the second, which starts in 18 months, will address the permitted upper levels of nutrients in supplements.

　　"The August legislation will have a major impact," says David Adams, director of the Health Food Manufacturers' Association (HFMA), which represents producers and suppliers such as Holland & Barrett, Solgar and Biocare. "There are some nutrient sources - such as selenomethionine, a widely used form of selenium, boron for bone health and chromium yeast for regulating blood sugar - that aren't on the list. Why should the Government infringe on people's choice to take supplements they think are good for them?" Britain has a thriving supplement culture and 21 million people - a third of all women and a quarter of men - spend ?335 million a year on tablets in the belief (misguided or not) that they will do them good and protect their health. But from August 1 you won't be able to buy them.

　　Scientists, nutritionists and dietitians agree: a plentiful and varied consumption of fruit and vegetables protects against cardiovascular disease, some cancers and even Alzheimer's. There is no scientific evidence that supplements do the same thing. The myriad nutrients contained in a single broccoli spear may react together for the benefit of the body; extracting a single nutrient may do little or no good.