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WEDNESDAY, Aug. 27 (HealthDay News) -- A chemical produced in the brain may play a role in regulating appetite and the likelihood of becoming obese, according to a new study.

For the study, researchers looked at a group of 33 people who had WAGR syndrome, a genetic condition that occurs in one in 500,000 to a million people. WAGR is an acronym for the symptoms that accompany the condition: Wilms' tumor (tumor of the kidneys), aniridia (absence of the iris), genital and urinary tract abnormalties, and mental retardation.

Some people with WAGR syndrome lack a gene for the brain chemical, brain-derived neurotrophic factor (BDNF). Animal studies have suggested that BDNF may help control appetite and weight.

The researchers found that 19 (58 percent) of the 33 study participants had deletions of all or a major proportion of one copy of the gene for BDNF and had correspondingly low blood levels of BDNF.

These 19 participants were all obese by age 10 and had a strong tendency to overeat. The participants who had two working copies of the BDNF gene, on the other hand, were no more likely to develop obesity in childhood than the general population and did not report unusually high levels of overeating.

"This is a promising new lead in the search for biological pathways that contribute to obesity," Dr. Duane Alexander, director of the U.S. National Institute of Health's Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), said in an institute press release. "This finding may eventually lead to the development of new drugs to regulate appetite in people who have not had success with other treatments."

The findings are published in the Aug. 28 issue of the New England Journal of Medicine.

According to senior study author Dr. Jack A. Yanovski, of the NICHD's Unit on Growth and Obesity, BDNF is thought to work in combination with a variety of other substances that regulate appetite and body weight, including the appetite-signaling hormone leptin.

Future research looking into the relationship between BDNF and leptin may lead to the development of new therapies for obesity.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about obesity.

FRIDAY, Aug. 22 (HealthDay News) -- You can have your steak and eat it, too, without producing harmful cancer-causing compounds, new research shows.

As a matter of fact, marinating meat in antioxidant-rich spice blends can reduce the risk of these heterocyclic amines (HCAs) forming by more than 80 percent.

"If you are concerned about carcinogens, marinating a product, and this would be any kind of muscle food product, is a good way to dramatically reduce the formation of HCAs," said study author J. Scott Smith, a professor of food science at Kansas State University. His research was published in the current issue of the Journal of Food Science. "The marinades would have to be rich in spices," Smith added.

And although the researchers didn't specifically check this, Smith suspects that the antioxidants found in red wine and in many fruits and vegetables might also do the trick.

HCAs are "suspected" human carcinogens produced in muscle foods that have been cooked at high temperatures. HCAs are created when heat acts on amino acids and creatinine in animal muscle.

Barbecuing produces the most HCAs, followed by pan-frying and broiling. Baking, poaching, stir-frying and stewing produce the least HCAs.

The researchers tested three different commercial marinade blends (Caribbean, Southwest and herb), purchased from a local grocery store, on fresh eye of round beef steaks.

The steaks (about 3.3 ounces each and one-fifth of an inch thick) were marinated for one hour (turning several times) in one of the blends, then cooked in a skillet at 400 degrees Fahrenheit for five minutes on each side.

Steaks marinated in the Caribbean blend had an 88 percent decrease in HCA levels. The herb blend reduced HCAs by 72 percent, while the Southwest blend reduced levels by 57 percent.

All the marinade blends contained two or more spices from the mint family, which are rich in the antioxidants rosmarinic acid, carnosol and carnosic acid.

The marinades contained maltodextrin and/or modified starch ingredients or salt that could have played a role in reducing HCA production due to water retention, the authors stated.

"We ate the beefsteaks, and they were edible," said Smith, who added that round steak was not his usual choice of steak. "I use these marinades at home."

The steaks were cooked on an electric skillet, but the results could probably be extrapolated to outside grilling as well. "Actually, a grill runs at higher temp, so the effect probably would be more dramatic," Smith said.

More information

Consumer Reports   has more on grilling basics.

WEDNESDAY, Aug. 6 (HealthDay News) -- Physical activity can reduce the risk of colon cancer, but few American adults are aware of this, a new study shows.

A sedentary lifestyle accounts for as many as 14 percent of all colon cancer cases in the United States. People who get lots of exercise have a 30 percent to 40 percent lower risk of developing colon cancer, according to study co-author Elliott Coups, of the Division of Population Science at the Fox Chase Cancer Center in Cheltenham, Pa., and colleagues.

But their analysis of survey data from 1,932 adults who answered questions about colon cancer risk found that only 15 percent said they used physical activity as a way of reducing their colon cancer risk. The findings were published in the August issue of Patient Education and Counseling.

Several factors may contribute to this lack of knowledge about the link between exercise and colon cancer risk.

"Patients may not be learning this information from their health-care providers and information regarding colon cancer prevention is not as well publicized as it could be," Coups said in a new release from the Center for the Advancement of Health.

Doctors may find it easier to tell patients about the general health benefits of exercise, rather than specifically referring to colon cancer, even if a patient has a family history of colon cancer or other risk factors for the disease.

"In the context of busy clinic visits, it is, in some ways, efficient for patients to be reminded that physical activity is good for their health in general. Going through each specific health benefit of physical activity would take considerable time," said Coups.

Sedentary people can greatly benefit from starting a modest exercise program, such as gardening or walking two to three hours a week, according to Dr. Edward Giovannucci, a professor at the Harvard School of Public Health.

"Sedentary people should first set such moderate, achievable goals. More benefits could accrue from higher levels and more intense exercise, such as jogging, running or tennis. To some extent, more may be better, but it is important to note that a little is much better than nothing," Giovannucci said in the news release.

More information

The American Cancer Society has more about colorectal cancer  .

MONDAY, Aug. 4 (HealthDay News) -- People who drink too much have increased odds of developing metabolic syndrome, a series of risk factors and conditions that are strongly related to cardiovascular disease, a new study says.

The study, expected to be published in The Journal of Clinical Endocrinology & Metabolism, defines excess drinking as more than two drinks per day for men or one drink a day for women. Binge drinkers are also considered to be at an increased risk.

Conditions of metabolic syndrome include obesity, high blood pressure and diabetes.

"Most people who consume alcohol in the United States drink in ways that may increase their risk of the metabolic syndrome and related conditions," study author Amy Fan, of the National Center for Chronic Disease Prevention and Health Promotion at the U.S. Centers for Disease Control and Prevention, said in a news release issued by the journal.

Fan cited a recent national survey that showed 58 percent of U.S. drinkers exceed the daily one- or two-drink a day guideline, and that just more than half of all drinkers had at least one episode of binge drinking in the past year.

For this study, researchers evaluated data from 1,529 people who consumed at least 12 alcoholic drinks in 12 months between 1999 and 2002. The participants, aged 20 to 84, were interviewed and had a physical examination that included a blood test.

"Prevention efforts should focus on reducing alcohol consumption to safer levels," Fan said. "Unfortunately, few physicians screen their patients about alcohol use or are knowledgeable about guidelines that define low-risk or moderate drinking."

She said public health messages should emphasize the potential cardiometabolic risk linked to drinking in excess.

More information

The U.S. National Heart, Lung, and Blood Institute has more about metabolic syndrome.