An increasing drive towards healthy eating and a move to reducing obesity has prompted a rise in the use of food supplements.
But knowing what you are eating has become increasingly difficult to answer thanks to processed food, high-intensity farming, and multivitamin tablets.
However, from August 1 it should become easier when the European Union Food Supplements Directive comes into effect. Food supplements will have to contain what they advertise on the label. Dangerously high-dose preparations will be banned, and clearer labelling should make it easier for consumers to get what they want.
Britain's Food Standards Agency (FSA) and the European Scientific Committee on Food have yet to decide permitted doses of vitamins and minerals, amid fears that over-consumption is a distinct problem.
Health food manufacturers say nearly 300 nutrients - minerals or compound sources of minerals and vitamins - could be needlessly banned. They argue that the safety of products excluded from an EU approved list has been established through years of use. They say the approved list is simply an extension of legislation regulating baby foods and is not appropriate for adults.
Manufacturers are challenging the EU proposals at the European Court of Justice in Luxembourg. The chief judge is expected to express his opinion next month. His opinion will be taken to be a key pointer, but a definitive ruling is due in July.
Peter Aldis, chairman of the Health Food Manufacturers Association, said the scheme conflicted with consumer freedom of choice and would put companies out of business.
Examples of products under threat include selenium, a rich source of health-promoting antioxidants, boron, which promotes healthy bone and skin growth and tocopherol, a constituent of vitamin E.
The food supplement industry has a reported turnover in the UK of £350 million a year, excluding internet and mail-order sales. Growth is 7 per cent annually.
To such an industry, the task of reformulating products to comply with the directive is not a huge financial burden. But, inevitably, the bill would be picked up by consumers, said Mr Aldis.
However, scepticism continues to surround much of the food supplement industry. Some food scientists say that if there was once a role for supplements, because of poor national nutrition, those days are largely past. So plentiful are foodstuffs, not least in countries such as France and Spain with large expat populations, that pill popping is a second best alternative and not without hazards.
The FSA advises: "Most people should be able to get all the nutrients they need by eating a varied and balanced diet. If you choose to take supplements it is important to know that taking too much or taking them for too long can cause harmful effects.
"Evidence suggests that fruit and vegetables are good for us, not just for the individual vitamins and minerals they contain, but because of the combination of the different nutrients and fibre you get when you eat them.
"So increasing the amount of fruit and vegetables you eat will benefit your health more than taking supplements."
Many people swear by a hefty dose of vitamin C to ward off colds. Supplements are said to help people with chronic fatigue, anaemia, irritable bowel syndrome, recurrent candida and arthritis.
Another problem is that people do not always stick to a balanced diet: the healthy food is available but it is not always taken up.
For the vast majority, especially expatriates in southern Europe with an abundance of fruit, vegetables and sun - a spur to vitamin D production - a healthy diet is what the doctor ordered. It even tastes good.