An independent panel of scientists is to meet this week to review recent scientific data on the soy compound genistein. The scientists expect to reach conclusions as to whether or not the consumption of genistein could have a negative impact on human development or reproduction.
The meeting, which will take place between Wednesday and Friday in Alexandria, Virginia, comes in response to growing public concern about the long-term effects of consuming soy.
Genistein, a naturally occurring plant estrogen- or phytoestrogen- in soybeans can mimic the effects of estrogen in the body. It is found in certain foods containing soy such as soy-based infant formulas, tofu, soy milk, soy flour, textured soy protein, tempeh, and miso.
Fourteen scientists will take part in the discussions, which are organized by the Center for the Evaluation of Risks to Human Reproduction (CERHR) of the National Institute of Environmental Health Services (NIEHS) and National Toxicology Program. The meetings will be open to the public.
"Soy products are often promoted as a natural, safe way to achieve at least some of the benefits of hormone replacement therapy in adults," said the NIEHS, adding that it is, however, necessary to "look at available evidence from reproductive and developmental animal and human toxicity studies, as well as exposure data from infants and women of reproductive age, to determine if phytoestrogens in soy infant formulas adversely affect human growth, development, or reproduction."
Indeed, soy infant formulas are growing in popularity, forming part of the diet of an estimated 10-20 percent of infants in the US. And, on the back of a number of health benefits linked to soy, sales of soy products in general have also been on the rise, after reaching around $4bn in 2003.
But a growing body of science has recently cast shadows over the widely accepted positive health effects of soy.
In January, the NIEHS released a study linking genistein to the disruption of the normal development of ovaries in female mice. This followed previous research by the NIEHS that showed that mice given genistein immediately after birth had irregular menstrual cycles, problems with ovulation, and problems with fertility as they reached adulthood.
And last year a team of UK scientists, headed by Dr Lynn Fraser, professor of reproductive biology at King's College London, revealed that genistein could damage human sperm.
Animal studies on genistein have previously raised other concerns. A 2004 study on newborn piglets found that the compound inhibited intestinal cell growth.
And in 2003, research on rats showed that males whose mothers were fed genistein did not achieve full sexual development as adults.
But the majority of scientific studies so far have focused on the health benefits of soy, and there is a growing awareness amongst consumers that the product is high in fiber, protein and minerals yet low in saturated fat and free of cholesterol.
In 1999 the Food and Drug Administration (FDA) approved an unqualified health claim linking consumption of soy foods to a reduced risk of coronary heart disease. According to a 2000 report in FDA Consumer, consumption of soy foods increased 20 percent per year since 1995 and the approval of this claim led to surging interest.
The link between soy and heart health was also recently reinforced when a study published in November revealed that soy protein containing isoflavones could help reduce two strong indicators for coronary heart disease in postmenopausal women.
Other studies have also indicated that components found in soy could help reduce cholesterol, prevent high blood pressure, alleviate menopause symptoms and maintain bone density.