Monday, July 12, 2010

Olive Oil May Protect Against Bowel Disease

Increasing your intake of olive oil may help protect against ulcerative colitis, a new study finds.

Ulcerative colitis is an inflammatory bowel disease that causes ulcers in the lining of the rectum and colon, resulting in abdominal pain, diarrhea and weight loss. This study found that people whose diet was rich in oleic acid were far less likely to develop ulcerative colitis.

Oleic acid is a monosaturated fatty acid found in foods such as olive oil, peanut oil, grapeseed oil, butter and some margarines.

This study included more than 25,000 people, aged 40-65, in Norfolk, U.K. who were recruited between 1993 and 1997. None of the participants had ulcerative colitis at the start of the study. By 2002, 22 participants had developed ulcerative colitis. The researchers compared the diets of these people to those who didn't develop the disease and found that those with the highest intake of oleic acid were 90 percent less likely to develop ulcerative colitis.

"Oleic acid seems to help prevent the development of ulcerative colitis by blocking chemicals in the bowel that aggravate the inflammation found in the illness," study leader Dr. Andrew Hart, of the University of East Anglia's School of Medicine, said in a news release.

"We estimate that around half the cases of ulcerative colitis could be prevented if larger amounts of oleic acid were consumed. Two-to-three tablespoons of olive oil per day would have a protective effect," he said.

The study was presented at the Digestive Disease Week conference in New Orleans.

Monday, October 19, 2009

Eating Habits in the Obese May Echo Drug Addicts' Patterns

When it comes to weight control, it might not be the kind of snack that matters, but who eats it.

When researchers gave similarly "sinful" snacks to obese and non-obese women, the healthy-weight women wanted less of the treat over time, but obese women kept wanting more.

"Obese and non-obese women respond to high-energy, high-density snacks in different ways," said Jennifer Temple, lead author of the study, which appears in the August issue of the American Journal of Clinical Nutrition. "For us, this underscores a need for really doing detailed studies comparing obese and non-obese women in terms of how they respond to food to try to understand things that work better to improve healthy eating."

"You can't take what you see in non-obese women and think it will automatically have the same effect in obese women," added Temple, an assistant professor in exercise and nutrition science at the University at Buffalo, in New York.

Such information could one day be useful in tailoring dieting strategies for different people.

According to background information in the study, only 10 percent of people who lose weight through dieting and exercise manage to keep that weight off for five years.

Scientists have postulated that one reason for the high failure rate is that people feel deprived of their favorite foods and end up making up for their period of abstinence.

In an earlier study, the same research team had found that "food reinforcement," the term they use to describe motivation to eat, decreased in non-obese women who were asked to consume their favorite snack, be it M&Ms or Oreo cookies, for days at a time.

"After two weeks of eating the same snack food, the women came back into the lab and said, "I don't ever want to see a potato chip again,'" Temple said. "They had no interest in working for the food."

But 300 calories is a large portion, so the researchers decided to do a similar study but with smaller (100-calorie) portions as well as the large portions. In addition, a third group of women consumed no snack calories. The study included 31 obese and 27 non-obese women.

All participants were asked to "work" for their food by performing tasks on a computer program set up as a sort of slot-machine. When all of the shapes on the screen matched, volunteers earned points toward eating.

The women were given pre-packaged portions of their favorite snack to eat every day for two weeks. Snacks tended to fall into one of two categories: high-fat and high-sugar (cookies, candy bars) or savory, meaning just high in fat (such as potato chips).

"For the zero and 100-calorie portions, the obese and non-obese groups looked the same," Temple said. "The food reinforcement didn't change before and after the two weeks, which would be expected."

However, non-obese women who snacked on 300-calorie portions exhibited no increase in motivation to eat, but motivation did increase in obese women who consumed the larger portion, the study found.

"They actually worked harder for the food," Temple said. "This was surprising to us. We had anticipated in the beginning that we might not see a decrease or as large of a decrease, but we didn't expect to see an increase."

In some cases, women reported still wanting the food even though they didn't like it.

The pattern is strikingly similar to that seen in drug addicts.

"We're exploring this idea of sensitization, which happens with drug use," Temple said. "Response to a drug will actually decrease over repeated use."

And that leads to more drug use.

"I stop short of calling overeating an addiction," she added. "I don't think it has all of the same properties, but I think we can learn something about overeating behavior from the drug world. We're applying the same experimental paradigms to food and trying to see if obese people might be more susceptible to having an increased response to repeated food administration."

Marianne Grant, a registered dietitian and health educator with the Texas A&M Health Science Center's Coastal Bend Health Education Center in Corpus Christi, said that something else could be at work.

"This suggests to me that people who were obese were not eating out of hunger," Grant said. "There was some other need that eating was filling for them."

"Everyone is different and approaches eating in a different way," she said. "What works for one person may not work for another person. Overeating may be because of some reason other than hunger. That issue needs to be addressed."


SOURCES: Jennifer L. Temple, Ph.D., assistant professor, exercise and nutrition science, University at Buffalo, State University of New York, Buffalo, N.Y.; Marianne Grant, R.D., registered dietitian and health educator, Texas A&M Health Science Center, Coastal Bend Health Education Center, Corpus Christi, Texas; August 2009 American Journal of Clinical Nutrition