Soy Health Claims Questioned
The "long and demanding" road to FDA approval actually took a few unexpected turns. The original petition, submitted by Protein Technology International, requested a health claim for isoflavones, the estrogen-like compounds found plentifully in soybeans, based on assertions that "only soy protein that has been processed in a manner in which isoflavones are retained will result in cholesterol lowering".
The abrupt change in direction was no doubt because a number of researchers, including scientists employed by the US Government, submitted documents indicating that isoflavones are toxic.
In early 1998, The FDA received the final British Government report on phytoestrogens, which failed to find much evidence of benefit and warned against potential adverse effects.
Even with the change to soy protein isolate, the FDA engaged in the approval process and had to nimbly with concerns about mineral blocking effects, enzyme inhibitors, goitrogenicity, endocrine disruption, reproductive problems and increased allergic reactions from consumption of soy products.
One of the strongest letters of protest came from Dr Dan Sheehan and Dr Daniel Doerge, government researchers at the National Center for Toxicological Research. Their pleas for warning labels were dismissed as unwarranted.
Evidence of soy's cholesterol-lowering properties is drawn largely from a 1995 meta-analysis by Dr James Anderson, sponsored by Protein Technologies International and published in the New England Journal of Medicine.
A meta-analysis is a review and summary of the results of many clinical studies on the same subject. Use of meta-analyses to draw general conclusions has come under sharp criticism by members of the scientific community.
There is the added temptation for researchers, particularly researchers funded by a company like Protein Technologies International, to leave studies out of a meta-analysis that would disagree with the desired conclusions. The author of the above meta-analysis discarded eight studies for various reasons, leaving a remainder of twenty-nine.
The published report suggested that individuals with cholesterol levels over 250 mg/dl would experience a "significant" reduction of 7 to 20 per cent in levels of serum cholesterol if they substituted soy protein for animal protein. Cholesterol reduction was insignificant for individuals whose cholesterol was lower than 250 mg/dl. For most of us, giving up steak and eating veggie burgers (soy protein) instead will not bring down blood cholesterol levels.
Studies in which cholesterol levels were lowered through either diet or drugs have consistently resulted in a greater number of deaths in the treatment groups than in controls - deaths from stroke, cancer, intestinal disorders, accident and suicide.
Cholesterol-lowering measures in the US have fuelled a $60 billion per year cholesterol-lowering industry, but have not saved us from the ravages of heart disease.