Saturday, October 20, 2007

Genes for overeating

Researchers say they've found a genetic explanation for why some people crave food more than others do. People who are driven to eat a lot may need more food than others do to get the same feeling of reward, the scientists claim.

The research, they said, found that people with genetically low levels of a brain chemical called dopamine find food to be more "reinforcing" than other people do. Dopamine, a neurotransmitteror substance that transmits nerve impulsesis associated with pleasure. Having less of it may prompt people to work harder to stimulate rewarding feelings, such as by eating, according to the scientists.

The findings, by investigators at the University at Buffalo, N.Y., appear in the October issue of research journal Behavioral Neuroscience. The lead researcher, Leonard Epstein, is also a consultant to comestibles giant Kraft Foods Inc. The team studied a gene variant carried by about half the population, called the Taq1 A1 allele. It leads to lower dopamine levels by producing lower amounts of a type of receptor, or molecular gateway, that allows dopamine transmission.

The researchers studied 29 obese and 45 nonobese adults, taking DNA samples and having them fill out questionnaires. They also asked the participants to rate various snack foodsbut this assignment was a sham. Actually, the investigators were examining how much participants ate when food was freely available.

Participants were also asked to perform a second task in which they could swivel between two computers. Pressing specified keys on one earned points to eat their favorite food; pressing keys on the other earned points to read a newspaper. The idea was for researchers to find out how hard the participants worked to obtain food, versus something else.

Both obesity and lowerdopamine gene variants predicted a significantly stronger response to food's reinforcing power, and more calorie consumption, the researchers found. Epstein differentiates reinforcing value, defined by how hard someone will work for food, from the "feel good" pleasure people get from food. "They often go together, but are not the same thing," he said.

"Food is a powerful reinforcer that can be as reinforcing as drugs of abuse," the scientists wrote. They added that the findings may help experts identify people at risk for obesity and develop treatments tailored to them. "Behavior and biology interact and influence each other," said Epstein. "The genotype [genetic makeup] does not cause obesity; it is one of many factors that may contribute to it," including learned habits.


Aspirin against heart disease: just for men?

The feminists keep telling us that the only differences between men and women are the product of a "patriarchal" culture so this cannot be right

First it was an apple; now it's a small aspirin a day that may keep the doctor away. Aspirin has become standard for heart attack prevention. But new research suggests it may really be a man's drug.

Scientists have long puzzled over why aspirin's protective effects vary widely among clinical trials. Some studies find it has no special effect; others, that it cuts heart attack risk by over 50 percent.

A new study from researchers at St. Paul's Hospital in Vancouver, Canada, highlights the influence of gender. Investigators examined 23 previously published clinical trials, involving more than 113,000 patients, and analysed how the proportion of men to women affected the the outcomes. "Trials that recruited predominantly men demonstrated the largest risk reduction in nonfatal heart attacks," said Don Sin, one of the authors.

"The trials that contained predominately women failed to demonstrate a significant risk reduction in these nonfatal events. We found that a lot of the variability in these trials seems to be due to the gender ratios, supporting the theory that women may be less responsive to aspirin than men for heart protection."

The reasons why are unclear, he said, though recent studies have shown that men and women have major differences in the heart's blood vessels. "We would caution clinicians on prescribing aspirin to women, especially for primary prevention of heart attacks," said Sin. "Whether or not other pharmaceutical products would be more effective for women is unclear; more sexspecific studies should now be conducted." The findings appeared Oct. 18 in the online research journal BMC Medicine.

A study published in the Journal of the American Medical Association last May recommended 75 to 81 milligrams of aspirin daily, taken in consultation with a physician, for longterm heart disease and stroke prevention



Just some problems with the "Obesity" war:

1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).

2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.

3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.

4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.

5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?

6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.

7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.

8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].


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