Thousands of Britons including infants, vegans and consumers buying dietary supplements in health shops should be involved in research on the risks and benefits from chemicals in plants, say the government's scientific advisers.
A huge programme to investigate the action of phytoestrogens, found in foods such as soy milk, tofu, lentils, chickpeas, alfalfa sprouts and cereals, has been recommended by those advising the food standards agency.
They say evidence from 3,000 studies worldwide is not sufficient to understand many health implications for our diets from the consumption of the chemicals which might mimic or disrupt hormones in our own bodies.
Even large studies involving Japanese and Chinese populations suggesting benefits might have little relevance for Europeans because of different lifestyles, diets, metabolisms and genetic make-ups.
More work is also needed to assess the impact of soy milk on the sexual development of infants and their immune systems. The scientists say the small numbers of children who have thyroid problems might be at risk from soy milk and recommend a review of guidance regarding the prescription of soy milk for infants who have an intolerance to cow's milk.
A consultation document drawn up by a working group of the committee on toxicity of chemicals in food also raises concerns about the use of dietary supplements and soy-enriched foods as "natural" alternative treatments for the menopause, osteoporosis, heart disease and some cancers. These might react badly with prescription drugs.
Frank Woods, chairman of the group, recognises the package might be expensive, and some studies would be difficult to organise because of the length of time needed. Stephen Walsh, a nutritionist with the Vegan Society, suggested there was no evidence that Britain's 250,000 vegans would be at risk of harmful effects if they stuck to a benchmark of traditional "oriental style" levels of around 10g of soy protein a day, equivalent to about 100g of tofu, or a large cup of soy milk.
"There is no evidence [in Japan] of a safety problem. Entire populations that have been eating the same products for thousands of years."
Heather Paine, of the Infant and Dietetics Food Association, representing the formula milk industry, said: " We think soy formulas are safe. We have been on them for over 40 years without a problem."
· Taking the herbal remedy ginkgo biloba could improve memory in people with dementia, according to a review of 33 trials over 25 years by the Alzheimer's Society and Cochrane Collaboration, which pulls together evidence from drug trials.
