"Junk" ingredient may be better than the real thing

Resveratrol supplements are highly popular on the Internet and elsewhere. This popularity stems from animal research findings, in which high doses of resveratrol produced some anti-aging and various other health benefits in the animals. One finding was that resveratrol appeared to impart protective effects against the onset of diabetes. It does this by helping to prevent high blood glucose levels, and also may prevent some adverse cardiovascular effects common in those with diabetes. This is significant because diabetes onset is on the rise throughout the world. While type-2 diabetes used to be called "adult-onset diabetes" because it was more common in those over age 40, early signs of diabetes, such as insulin resistance, are turning up in children as young as 12. The increased incidence of diabetes is linked to both poor diets, rich in fructose and trans fats, as well as physical inactivity.
     The problem with resveratrol as a cure-all is twofold. For one, the dose supplied in animal studies are far higher than is ever consumed naturally.Red wine is one of the richest sources of natural resveratrol, yet the amounts provided of resveratrol in animal studies are equivalent to thousands of bottles of wine. Another problem with resveratrol is that there is little or no human evidence that it provides similar benefits to that shown in animal research. But this doesn't stop countless human guinea pigs from self-dosing themselves with megadoses of resveratrol in the belief that it will both make them healthier, as well as slow the aging process.
   As you might expect, resveratrol supplements aren't cheap. To use the doses frequently suggested on various Internet sites could cost a few hundred dollars per month. One measure of the quality of resveratrol supplements is purity. This is measured by the percentage of the active isomer of resveratrol, trans resveratrol. The higher the content of trans resveratrol, the more expensive the supplement. Nearly all resveratrol supplements are derived from a plant called polygonum cuspidatum, most of which emanates from China. One of the other ingredients in this plant is a substance called emodin, which is considered undesirable by those who use high dose resveratrol supplements because it produces laxative effects. As such, frequent warnings are often voiced on various Internet longevity forums about only using "high quality" resveratrol supplements,lest you be exposed to the hidden dangers of emodin in lower grade supplements.
   An ironic aspect of this is that emodin is pretty good stuff. Studies show that it may help prevent various types of cancer, independent of any resveratrol effect. More recent studies show that it may be a potent preventive against the onset of type-2 diabetes. Animal studies show that emodin provided to mice with diet-induced obesity (the primary diabetes risk factor) lowers elevated blood glucose and insulin levels, and also improves insulin resistance, the first stage of diabetes. Even more impressive, however, is that emodin inhibits an enzyme called 11B-HSD-1 that works to convert inactive cortisone into active cortisol. This enzyme is known to be active in fat cells, and there is a theory that overactivity of the enzyme in fat cells both promotes and perpetuates obesity, particularly in the central part of the body, or trunk. This type of fat is considered most dangerous to health because of an association with diabetes and CVD onset. Excess levels of cortisol produced by the enzyme oppose the actions of insulin,leading to insulin resistance.
     If emodin proves as effective in humans as it is in mice, it will be a potent preventive against the onset of both diabetes and cardiovascular disease. And yes, in large doses in may also act as a laxative. But considering how many people have a problem with  that, too, I'd say that's a bonus effect of emodin.

Source: http://appliedergogenics.blogspot.com/2010/08/junk-ingredient-may-be-better-than-real.html