The Whole Soy Story

Dear Kaayla:  If soy isoflavones are so deleterious to our brains, then why do menopausal women always get told to combat their hot flashes with soy isoflavones? Doesn’t this just hasten the overall aging, starting with the brain?  So what should we do instead–maybe red clover?

Dear Wendy:  The soy industry heavily promotes the myth that soy is safe and all-natural HRT and the ticket to a healthy and easy menopause. The truth is the studies on soy and menopause are inconsistent and contradictory at best. Soy might alleviate hot flashes in some women, but there are well proven risks to the thyroid. Red clover contains coumestans, another type of phytoestrogen. In terms of a comfortable passage through menopause, I’d recommend a Nourishing Traditions type diet perhaps with some heavy metal detoxification, adrenal support, thyroid nourishment, liver cleansing and other work as indicated by laboratory assessment and work with an alternative MD or other health care practitioner. Good luck.

Dear Dr. Daniel,    I would like to take PC,  GPC and PS as part of my anti aging program   These products come from soy.   Do you see a downside for me?   –    Jon

Dear Jon:   I can’t really evaluate your situation since I am not familiar with your diet, lifestyle, health history or lab reports.  That said, phosphatidyl choline glycerylphosphorylcholine  and phosphatidyl serine are widely recommended by alternative medical doctors and other health practitioners as anti-aging supplements that can promote and preserve brain function and mental acuity. They are also widely included in nutritional protocols designed for people suffering from Alzheimer’s disease, Parkinson’s disease, and for those recovering from damage from stroke.

However, they might not work as well as you might hope.  The fact that PC, GPC and PS products almost always derive from soy oil is problematic on a number of levels.  First of all, most of the scientific studies proving the efficacy of phosphatidyl serine come from bovine sources, which also contain DHA as part of the structure.  Because of the Mad Cow scare, bovine-derived PS isn’t likely to show up in the marketplace soon.

The biggest problem with a vegan version of PS  is that plant oils never contain ready-made DHA. Indeed, the entire fatty acid structure of soy-derived PS is different from that of bovine-derived PS. The latter is rich in stearic and oleic acids, while soy PS is rich in linoleic and palmitic acids. Complicating matters further,  Dr. Mary Enig, PhD, MACN, has pointed out that the PS naturally formed in the human body consists of 37.5 percent stearic acid and 24.2 percent arachidonic acid.  Despite these differences, soy-derived PS has proved helpful to many people.

A fish oil or egg-derived PS, which would naturally contain DHA, would probably perform better in the body and brain than any plant- sourced product.   I have heard of at least one company — Enzymotec USA — that hopes to bring such a PS to the market soon.   Although a sunflower oil-derived PS would also fail to match the superior fatty acid structure of animal sourced PS, it would offer the advantage of being soy free and thus suitable for the growing numbers of people who are allergic to soy.

Dr Daniel,  Does anyone know if soy lecithin has been linked to the brain shrinkage problem? I’ve heard tofu will damage my brain.   Is my brain safe with lecithin?  — Fred

Dear Fred:    I  think you might be referring to the work of Dr. Lon White, a neuro-epidemiologist with the Pacific Health Institute in Honolulu.   Dr White and colleagues showed that men and women who ate tofu at least twice per week experienced accelerated brain aging, diminished cognitive ability and were more than twice as likely to be clinically diagnosed with Alzheimer’s disease.  MRI scans showed enlarged ventricles while autopsies revealed atrophied brains with lower weights. Subjectively, the researchers couldn’t help but notice that by age 75 to 80, the tofu eaters looked about five years older than those who had abstained.

The soy industry claims “the tofu effect” is just a fluke, but the statistical probability of the results being true varied from 95 to 99 percent, depending upon the particular brain aging endpoint. The investigators also searched for – but failed to find – confounding factors such as age, education, obesity or other food and drinks.   The study has earned high marks from researchers not on the soy industry’s payroll, including Dan Sheehan, PhD and Daniel Doerge, PhD at the FDA’s National Laboratory for Toxicological research in Jefferson, Arkansas.who stated, “Given the great difficulty in discerning the relationship between exposures and long latency adverse effects in the human population and the potential mechanistic explanation for the epidemiological findings, this is an important study. It is one of the more robust, well-designed prospective epidemiological studies generally available.”

White has hypothesized that the isoflavones in tofu and other soy foods caused the adverse effects in the brain. In fact, numerous animal studies show that soy isoflavones interfere with an enzyme called tyrosine kinase in the hippocampus, a brain region involved with learning and memory. Elevated levels of phytoestrogens in the brain also cause decreases in brain calcium-binding protein (needed for protection against neuro-degenerative diseases) and in brain-derived neurotrophic factor (essential to the survival and genesis of brain cells). Finally the soy isoflavone genistein reduces DNA synthesis in the brain, reducing the birth of new brain cells and promoting apoptosis and cell death.  For references, go to The Whole Soy Story: The Dark Side of America’s Favorite Health Food, pages 307-308.

It is important to state clearly here that soy oil contains low or no isoflavone content, and that a lecithin, derived from soy oil would be highly unlikely to contain isoflavones.   The above studies linking soy to cognitive decline are irrelevant in terms of health risks from lecithin .  But given the fact that soy has been linked to cognitive decline, dementia, brain atrophy and neurodegenerative disease, it would not be wise to start swigging soy milk or feasting on tofu.

Kaayla T. Daniel, PhD, CCN, is The Naughty Nutritionist™ because of her ability to outrageously and humorously debunk nutritional myths. A popular guest on radio and television, she has appeared on The Dr Oz Show, ABC’s View from the Bay, NPR’s People’s Pharmacy and numerous other shows. Her own radio show, “Naughty Nutrition with Dr. Kaayla Daniel” debuted this spring on World of Women (WOW) Radio. Dr Daniel is the author of The Whole Soy Story: The Dark Side of America’s Favorite Health Food, a popular speaker at Wise Traditions and other conferences, a Board Member of the Weston A. Price Foundation and recipient of its 2005 Integrity in Science Award. Her website is www.naughtynutritionist.com and she can be reached at Kaayla@DrKaaylaDaniel.com.