Heart group(American Heart Association) finds few health benefits from soy

CBC News ^ | Mon, 23 Jan 2006 | Staff

[Lil'freeper]

[M. E. Hanke, "Biochemistry," Encycl. Brit. Book of the Year, 1948.]

Current science disagrees with the obscure encyclopedia citation. Your link is quite interesting but isn't credible to me - this Dr. Peat does his readers a great disservice by mixing facts with half truths and coming to some wild conclusions. For instance, it is true that the body can assemble a variety of fats. Some, but not all. It can make saturates. It can make unsaturates. It can make w7's and w9's, it can make Mead acid, but it cannot make the w6's and w3's. Hence they're called "essential".

In the past, when the fatty acids were first identified they were called "essential" for normal growth and development. In today's science, the term "essential" has a much narrower definition. It means the substance cannot be synthezied in the body and must be obtained from dietary sources. Because some fatty acids can be synthesized by the body they are obviously not 'essential' by current definition. I think the encyclopedia excerpt is attempting to clarify this point and as such does nothing to refute what is settled science. To the extent that it names w3 and w6 as non-essential, it is simply wrong.

Again, I'd be very interested in reading something (fairly current) from a peer-reviewed journal that establishes the pathways for w6 or w3 synthesis in the human body. Perhaps this Dr. Peat has published such revolutionary research. I doubt it. In the mean time, I encourage you to read more widely and to challenge what you read by looking at the supporting science.

Here's a start: W.E.M. Lands (1992). Biochemistry and physiology of n-3 fatty acids. FASEB J 6: 2530-2536.
Another reference of interest is Mary Enig's "Know Your Fats" which is written as a primer to lipid chemistry. She also makes the case that unsaturated seed-oils are not health-promoting but does a far better job of it.

[Colorado Buckeye]

Thanks for your informative reply. And for those that aren't used to translating between the Roman and Greek alphabets, when you write w3, you refer to a fat that many of us refer to as omega-3.

[Lil'freeper]

no prob. The article I linked is a really, really good read - very frank about the limits of the current science. Near the end is a discussion of fitting the data to a curve: "Once the nonlinear hyperbolic nature of ... the actions ... is recognized, previously linear comparisons can be recognized to be merely incomplete and not contradictory." This is a nice concept when applied to the bigger picture. Human bodies are complex organisms but we crave simple cause-effect relationships to explain how it works. We want everything to fit to a line. Lines are easy.

I suspect topics like soy, cholesterol, antioxidants, alcohol consumption, etc, that go back and forth, good one day, bad the next, are never going to fit to a line or a hyperbola or anything simple. Not with genetics, metabolism, nutrition, environment, and pharmecuticals all interacting with each other. We just have to hang in there and keep learning.

And ugh. There are four names for everything in biochemistry. omega-3's, w3's, n-3's, PUFA's, It's just crazy. :0