Soy: A common food with unclear benefits

Saturday May 9, 2009 (foodconsumer.org) -- Soy, a common ingredient in many foods, has come under scrutiny lately as scientific reports are questioning its status as a “superfood.” The legume, which is also a common food-additive, is under suspicion for causing a variety of maladies from impaired male fetal development to cancer. Yet, as studies come out with conflicting information, the underlying question remains; should we eat soy?

The soybean, also referred to as the soja or soya bean, is a legume, like peanuts or peas, and has an edible seed. The Encyclopedia Britannica states that it is the most economically important bean in the world, as it nourishes millions and supplies the ingredients for a vast array of chemical products. It is found in tofu, many breakfast cereals, vegetarian foods, scores of other products, and it is also eaten by itself.

Mail Online, the website of the British news organization the Daily Mail, reports that a heavily refined form of soy appears on food labels as ‘soya flour,’ ‘hydrolysed vegetable protein,’ ’soy protein isolate’, ‘protein concentrate,’ ‘textured vegetable protein,’ ‘vegetable oil,’ ‘plant sterols,’ or the emulsifier ‘lecithin.’ The news organization also reports that soy contains high levels of a class of chemicals known as “phytoestrogens,” which mimic the female hormone estrogen. Dr. Margaret Ritchie of the University of St. Andrews told the organization that “if a woman is low in estrogen, as in the menopause, the extra estrogen absorbed when soya is eaten can help relieve menopausal symptoms.”

However, a number of sources report that high consumption of soy may contribute to infertility in developing males if consumed by a pregnant mother. Dr. Allan Pacey of the University of Sheffield told British newspaper the Independent that the phytoestrogens “may affect the initial development of the testicles if a woman eats lots of soya products.” However, the article goes on to quote Dr. Justine Butler of the Vegetarian and Vegan Foundation, who states that a decision by the British Department of Health to consult a General Practitioner before consuming soy is “based largely on unfounded anecdotal evidence and animal-based experiments.”

Dr. Butler told the newspaper that “if [her] research flagged up any areas of potential - and [she] stress[es] potential - risk, it would be for post menopausal women with estrogen-dependent breast cancer and possibly people with hypothyroidism, as a limited number of studies have suggested that isoflavones may affect thyroid function by lowering these concentrations of thyroxine.” Indeed, Dr. Butler’s opinion seems to be echoed by a number of other professionals. While there are experiments to indicate that soy may be dangerous, they are largely inconsistent with the opinions and methods of the larger scientific community. It seems that the final say is that soy, as with all things, should be consumed responsibly and according to recommended portions.

(By Will Levine, and edited by Heather Kelley)