Peer-reviewed studies reveal inconsistent findings
United States The US Food and Drug Administration has called for public comment as it continues its investigation into soy-based health claims it officially approved in 1999.
The FDA decided to re-evaluate the claims after scrutinising peer-reviewed studies that found soy had little or no effect in cancer and heart-disease prevention. It's a rethink that comes in the wake of statements from influential groups such as the American Heart Association questioning soy's potential to reduce LDL cholesterol levels.
The FDA's recognition that study findings have been inconsistent spurred its review, even as it acknowledged some studies demonstrated soy's ability to positively affect health. One such study published in 2008 in the Journal of Nutrition concluded soy isoflavones could improve blood circulation in rats bred to develop hypertension.
The FDA released a study review in 2005 that concluded soy products could exert a small benefit on LDL cholesterol, which was viewed by the soy industry as a back-handed compliment. A 'small benefit' did not equate with the stated benefits of the approved claims, and left many wondering if it was the beginning of the end of the claims that had played a significant part in driving soy products into the American consumer mainstream.
The FDA also qualified this qualified finding by stating while this 'small benefit' could be derived from consuming soy products, it was not clear if that benefit was due to soy protein or some other constituent part of a variety of soy products.
The official claims being re-evaluated:
- Dietary lipids and cancer
- Soy protein and coronary heart disease
Qualified claims being re-evaluated:
- Antioxidant vitamins and the risk of certain cancers
- Selenium and certain cancers