Tuesday, June 26, 2007

The Obesity Gene

You know those annoying people who can eat anything they want without gaining a pound? They never have to think about whether they should have an extra piece of lasagna; for them it's all about whether they want another piece. They don't even have to go out and run a marathon after dinner, either. Skinny is just wired into them. My husband is one of these fortunate souls. People started telling him when he was twenty-five, "Just wait until you're thirty. Then you'll start padding up." Then it was, "Wait until you're thirty-five." "No really, wait until you're forty." We're now hearing the same rhetoric about forty-five, but I suspect that that age will also pass without the weight cascade that others portend. I'm not sure why people feel the need to promise that the pounds are just around the corner, but my guess is that it's just too annoying to watch his slender frame reaching for another cookie, knowing it won't settle anywhere on his body. It's just not fair, and they have to comfort themselves with the notion that someday he'll have the same struggles as everyone else.

Then there are the people at the other end of the spectrum. It seems they could live on a diet of celery and water, and still have to squeeze into their Levis at the end of the day. No amount of dieting really pays off. As soon as they eat anything with the least bit of flavor, they puff right back up, like a human air bag in a head-on collision with the refrigerator. These are the people who find my husband and others like him the most annoying. (Can you blame them?) Something does seem to be really off in this equation. How can some people be so naturally thin, and others so naturally padded? Most of us try to keep our weight in balance by some combination of reasonable caloric intake and exercise, but there are people at both ends of the weight chart who just don't fit the mold, and nothing seems to make them. Why is that?

I found an article at Eureka Alert! that might just explain why, and more to the point, also suggests what can be done about it. Scientists at the Mayo Clinic are learning that maybe the problem of obesity might just be the result of a specific gene--a gene that can, in effect, be turned off. Dr. Eduardo Chini says that genes play a role in obesity about 50 percent of the time. He and a group of researchers at the Clinic have been conducting studies on mice that indicate that a deficiency in CD38, a gene which helps regulate energy metabolism, protected the mice from becoming obese, despite high-calorie, high-fat diets. Let me restate that--not having this gene meant that the mice ate high-calorie, high-fat foods, and didn't gain weight:

Researchers studied two groups of mice: one with the gene CD38 and the other without. Each group was fed a high-calorie diet with 60 percent of calories from fat. In a second test, each group was fed a standard diet in which 4 percent of calories came from fat.

As a result, the body fat of mice that carried CD38 and were on a high-fat diet nearly quadrupled and their body weight almost doubled. After eight weeks on a high-fat diet, mice with CD38 began to show signs of glucose intolerance, one of the first indicators of diabetes onset. In addition, this group of mice lived for only four-to-six months compared to the second group of mice that lived for 12 months.

For the group of mice that did not carry CD38, their body fat and weight did not change even though they were on a high fat diet. These mice burned more energy, were leaner and otherwise healthy.

“These changes contributed to the ability of these mice to fend off weight gain despite a high-fat diet and lack of exercise. Together these results suggest that a CD38 deficiency has a protective effect against high-fat, diet-induced obesity,” Dr. Chini says.

Okay, it looks like those people (or at least mice) who are lucky enough to be deficient in this little obesity gene (I'm betting my husband is a member of that club) have a natural "immunity" to gaining weight, which is why lasagna doesn't last very long here at Chez Meow. Note, too, that the mice without the gene lived longer and were healthier--nice bonus winnings in the gene lottery, wouldn't you say? What about the people who are just bursting with CD38, though, the ones who hear the word lasagna and put on five pounds? What's the hope for them? Here's the part that could get some people excited. Apparently, CD38 can be suppressed, or its effects can, anyway:

Dr. Chini and colleagues also examined the effects of resveratrol in mice. Resveratrol is a naturally occurring substance found in some plants such as mulberries, peanuts and red grapes used to make wine. It has been marketed as a drug that mimics the effects of moderate exercise without the physical act of exercising and also as a longevity drug, despite the lack of evidence that resveratrol is safe and effective in humans.

From the evidence the mice provided, the marketing might not be entirely misleading, because, "Researchers found that mice with CD38 that were treated with resveratrol for two weeks were protected from high-fat, diet-induced obesity." Time to add peanuts and red wine to the grocery list, eh? It will be interesting to see where this goes. I've seen the ads for those "miracle" pills, the ones that promise that you can eat all you want, lay around on the couch, and end up with the body of a supermodel in just three months, and always assumed they were just another scam. Now, I still think they're probably a scam, but who knows, maybe scientists are on the trail of something that might give some hope to those folks who can't seem to win the battle of the bulge, no matter how hard they try. Hey, if suppressing the effects of the gene works in mice, why not see where it could lead for people? As long as they don't discover that CD38 also regulates breathing, or something. Suppressing breathing would be bad, and probably not helpful for that life-extension they were mentioning earlier.