We have a major confession from the National Institutes of Health! The agency actually admits it’s been supporting research on soy and health for many years but is clueless about if and when soy prevents or cures much of anything. Or has even been proven safe! After commissioning a thorough review of the literature (http://www.ahrq.gov/clinic/tp/soytp.htm), NIH found a “large but weak literature with equivocal findings” and “some troubling data about soy products used in research, which included confounding produced by unanticipated levels of phytoestrogens in animal feed” (Heindel et al. Environmental Health Perspectives 2008:116(3);389-393). In other words, to ascertain the benefits of soy, scientists compared its effects in animals to animals fed a control diet full of soy, a poor way to design any study but a great way to hide the negative effects caused by soy feeding.
The official conclusion of the review, written in the finest scientese: “Given the large amount of heterogeneity and inadequate reporting, particularly related to soy protein and isoflavone dose, many questions remain as to whether specific soy products in adequate doses may be of benefit in specific populations. Further, well-conducted studies are needed to clarify the effect of soy dose on lipid parameters and to determine whether soy components other than protein or isoflavones may be responsible for the lipid effects seen.”
To help sort things out, the NIH plans a workshop for nutritionists, scientists, MDs, epidemiologists, biochemists and clinical trialists from academia, industry and government. Their job will be to figure out how to guide “the next generation of soy protein and isoflavone human research.” A key task is to identify methodological issues relative to exposures and interventions that may confound study results and interpretation and to find ways to deal effectively with these issues in the design, completion, reporting and interpretation of studies. NIH also hopes this group will address issues related to exposure to soy and other phytoestrogens, factors influencing variability of response and negative consequences of exposure. Sounds to us like a belated admission that soy might have a “dark side.” Interesting that I haven’t been invited.