and a word about hormesis. MCM
From Josh Mitteldorf: Both sides of the soy story The soy story is complex, and it is often difficult to know what foods are best for us in the long run. The reason is that nature so frequently fools us when we trust to theoretical arguments, or when we extrapolate from toxicity tests. Some things that are terrible for us in large doses turn out to be very beneficial in small doses. So we really must turn to long-term epidemiological studies. These take decades to complete, and even worse, you can't do controlled experiments on humans, so you're stuck using huge databases and trying to separate all the different factors that make one person different from another. These large-scale studies are a statistician's nightmare, and it's very easy to draw the wrong conclusions. With that qualification: There seems to be evidence that soy is good for cardiovascular health, linked to lower rates of heart disease and stroke, especially if it is a substitute for meat. On the other hand, there is evidence that soy consumption promotes dementia and Parkinson's disease. As a vegetarian seeking to diversify protein sources, I eat soy in moderation. I maintain my own page of suggested health practices ideas at <http://AgingAdvice.org/>http://AgingAdvice.org. Here's some background for those who are interested: Chromium and selenium are both quite toxic, but in tiny doses selenium helps prevent cancer and chromium can protect against metabolic syndrome. It gets stranger: Lab animals exposed to chloroform live longer than those that are not. Semi-starvation is the most reliable way to extend life span of many animal species. In some experiments, protein deprivation extends life span. Exposure to pathogenic bacteria, and even radiation exposure in modest amounts has been shown to extend life span. You can make rats live longer by trapping them in ice-cold water several hours a day. Recently, a worm was genetically modified to live ten times as long. The modification was to delete both copies of a gene essential to the cell's antioxidant defense! The root of all these paradoxes is a phenomenon called hormesis. For those of us over 40, the worst threats to our bodies by far come from the body's gradual self-destruction with age. If we can modulate the rate of aging, that might have more effect on our health than protecting ourselves from damage. And as it turns out, the body responds to many kinds of insults by overcompensating, and this is what is called hormesis. The body becomes stronger, slows the rate of aging, and protects itself much better against damage. The best-known example of hormesis is exercise. Exercise increases wear and tear on the body, produces free radicals like crazy, and burns energy that could otherwise be used for repair and maintenance. Yet vigorous exercise extends life expectancy for animals and for people, protects from cancer, heart disease and diabetes, and is the most reliable and long-lasting antidepressant. Many toxins - but not all - have a hormetic effect. You're best off avoiding lead and mercury absolutely. It's the body's tendency to overcompensate that makes the process work. If you're curious why evolution has arranged for the body not to do its best unless it is stressed, here's an essay I wrote for The Humanist on evolution and aging: <http://findarticles.com/p/articles/mi_m1374/is_1_62/ai_82013457/>http://findarticles.com/p/articles/mi_m1374/is_1_62/ai_82013457/ - Josh Mitteldorf --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to Mark Crispin Miller's "News From Underground" newsgroup. To unsubscribe, send a blank email to newsfromunderground-unsubscr...@googlegroups.com OR go to http://groups.google.com/group/newsfromunderground and click on the "Unsubscribe or change membership" link in the yellow bar at the top of the page, then click the "Unsubscribe" button on the next page. For more News From Underground, visit http://markcrispinmiller.com -~----------~----~----~----~------~----~------~--~---
