October 12, 2009
Antioxidants Increase Insulin Resistance In Mice
Everything in moderation.
We've all heard about the damage that reactive oxygen species (ROS) – aka free radicals – can do to our bodies and the sales pitches for antioxidant vitamins, skin creams or "superfoods" that can stop them. In fact, there is considerable scientific evidence that chronic ROS production within cells can contribute to human diseases, including insulin resistance and type 2 diabetes.
But a new report in the October 7th Cell Metabolism, a Cell Press publication, adds to evidence that it might not be as simple as all that. The researchers show that low levels of ROS – and hydrogen peroxide in particular -- might actually protect us from diabetes, by improving our ability to respond to insulin signals.
Unfortunately, toxins are essential elements of human metabolism. We use reactive oxygen species to perform essential functions at the expense of aging more rapidly. This is why we need to develop the ability to do repairs: Fix cells, replace cells, and replace whole organs.
There really is too much of a good thing. At least when it comes to food. I still haven't come across an equivalent report for sex.
"Our studies indicate that 'physiological' low levels of ROS may promote the insulin response and attenuate insulin resistance early in the progression of type 2 diabetes, prior to overt obesity and hyperglycemia," said Tony Tiganis of Monash University in Australia. "In a way, we think there is a delicate balance and that too much of a good thing - surprise, surprise - might be bad."
Tiganis' team found that mice with a deficiency that prevented them from eliminating physiological ROS didn't become insulin resistant on a high-fat diet as they otherwise would have. They showed that those health benefits could be attributed to insulin-induced signals and the uptake of glucose into their muscles. When those animals were given an antioxidant, those benefits were lost, leaving the mice with more signs of diabetes.
About 5 months ago some Harvard, Leipzig and Jena University researchers also reported vitamins C and E reduce exercise benefits and interfere with glucose metabolism in ways might boost diabetes risk. Also see my 2004 post Excessive Antioxidant Activity Risk Factor For Type II Diabetes. Vitamins are not a panacea. Stem cell therapies, gene therapies, and nanobot repair machines - they are the panacea!
Oh, come on. Every time antioxidant supplementation is studied, it either increases risk or does no good. It isn't news.
People spout about how good antioxidants are because they're in the business of selling them. Same for vitamins.
The lesson? The health media is bad at what it does (I include you as a sometimes offender, Randall). They are far too eager to hold on to ideas in the face of evidence.
Antioxidant vitamins alone per se might be questionable. But plant derived phytochemicals are a different thing. Things like blueberry extracts have been shown to delay|prevent brain aging(in animal models) and promote brain function, turmeric has anti-cancer activity, ginkgo is said to partially-reverse aging related morphological changes in mitochondria(in animals), green tea compounds have cardiovascular protective effects, etc. Many of these fruit|vegetable compounds have the ability to increase circulation, protect against cardiovascular disease, against cancer, protect the brain against short periods of lack of oxygen(as happens in accidents, reducing the extent and severity of brain damage resulting from cutting the oxygen supply temporarily to animals. It should be noted that some of these compounds also protect against neuro-toxin exposure.), and have anti-inflammatory properties.
Resveratrol is said to increase insulin-sensitivity, and also cause changes in muscle tissues akin to having performed exercise resulting in substantial improvements in endurance(animal models), besides strong cardiovascular protective, brain protective, anti-cancer activity(It should be noted that in-vitro it tripled human cell survival after exposure to gamma radiation, iirc, that is it seems to affect human cells). If this compounds and|or derived-drugs(Some in non-published studies even resulted in life-span increases in non-obese mice) can be delivered and has a similar effect on humans, it would seem like the effects would be stupendous.
As for vitamins, according to the Life extension foundation(LEF) formulations, some benefits can be obtained from slightly higher doses than the RDA. Supposedly this is based on analysis on multiple peer-reviewed scientific studies.(I haven't looked into it.) In any case provided no-deficiency is taking place, I haven't seen anything as dramatic [with these] as what is seen as a result of use of plant extracts|non-vitamin-compounds.
If the benefits of exercise are due to oxidative stress, I wonder if it would be possible to duplicate them with hyperbaric oxygen.