TUESDAY, Oct. 2 (HealthDay News) -- Chinese researchers have outlined the molecular chain of activity that makes resveratrol, a chemical found in the skin of red grapes and in red wine, a promising candidate for treatment of diabetes and other conditions.

The study focused on how resveratrol improved the sensitivity of mice to insulin, an effect that could lead to new treatments for type 2 diabetes, in which human cells lose their sensitivity to insulin.

And U.S. experts said the chemical's effect on a number of different tissues could eventually lead to such dreamed-of medications as an effective diet pill.

The study, by researchers at the Chinese Academy of Sciences in Shanghai, showed that resveratrol activates an enzyme called SIRT1. This enzyme, in turn, suppresses the activity of a molecule called PTP1B, which ordinarily works to decrease insulin activity. SIRT1 levels were reduced in the animals' insulin-resistant cells. Increasing SIRT1 activity with resveratrol improved insulin sensitivity by acting on PTP1B.

The study is published in the October issue of Cell Metabolism.

"When you suppress PTP1B, insulin activity improves," said Young-Bum Kim, an assistant professor of medicine at Beth Israel Deaconess Medical Center in Boston, one author of an accompanying editorial in the journal.

"SIRT1 has a variety of functions in the body," Kim said. "Now we can move on to other tissues, such as the brain. It is possible that regulating the hypothalamus with SIRT1 can prevent diet-induced obesity."

That is clearly a long-term goal, said Janice M. Zabolotny, an instructor in medicine at Beth Israel Deaconess, and the other author of the editorial.

"But it can make animals want less food and lower body weight," she said. "By activating SIRT1, you could block the expression of PTP1B and get the same hopeful benefit."

But clearly, "further studies are needed by other researchers and on different tissues in animals," Zabolotny said.

One striking finding was that much lower levels of resveratrol than in previous trials were able to increase the animals' sensitivity to insulin.

"This paper is different from previous reports in that lower doses were effective," Zabolotny said. "The reason for the difference is unclear."

A statement by Qiwei Zhai, lead author of the report, recommended caution to resveratrol enthusiasts, noting that those who have been drinking red wine might "think about drinking less."

Previous studies had indicated that a human would have to drink about 120 liters of red wine in a day to get the benefit seen in animals. The new results reduce that amount to a still-substantial three liters.

"An even better option may be to find other natural foods enriched with resveratrol or foods supplemented with resveratrol," Zhai said.

More information

To learn more about resveratrol, visit Oregon State University  .

THURSDAY, Sept. 27 (HealthDay News) -- Foods high in compounds called advanced glycation end products (AGEs) -- such as hamburgers, french fries and other fatty foods cooked at high temperatures -- cause a short-lived but significant dysfunction in blood vessel dilation that can lead to heart disease, a new study suggests.

"Although the effect was temporary, it suggests that AGEs could, over time, pose a significant risk to the vascular integrity of both diabetic and healthy persons," lead researcher Dr Jaime Uribarri, of the Mount Sinai School of Medicine, said in a prepared statement.

His team published its findings in the journal Diabetes Care.

High levels of AGEs are formed when foods rich in protein and fat are cooked at high and dry heat, including broiling, grilling, frying or roasting. Foods that are steam-cooked or stewed tend to have lower AGE concentrations, the researchers explained.

Previous research has found AGEs to be associated with a number of diabetes-associated chronic conditions, such as heart disease. This study found that consuming an AGE-rich beverage caused significant endothelial dysfunction in both people with diabetes and in people without diabetes.

Endothelial dysfunction is an early indicator of hardening of the arteries (atherosclerosis), which leads to heart disease, the study authors noted.

More information

The MedlinePlus Medical Encyclopedia has more about heart disease and diet.

WEDNESDAY, Sept. 26 (HealthDay News) -- Although eating lots of fruits and vegetables is good for your health, doing so will not reduce your risk for colon cancer, a Canadian study finds.

But fruits and veggies can still help ward off heart diseases and other cancers, one expert says.

"We know that fruits and vegetables are healthy and help prevent chronic diseases, especially cardiovascular disease," said Marji McCullough, a nutritional epidemiologist at the American Cancer Society. "Eating fruits and vegetables also helps prevent weight gain, which is also related to chronic disease including cancers," she added.

Those include cancers of the mouth and pharynx, esophagus, stomach, colon-rectum, larynx, lung, ovary, bladder and kidney.

In their review of the data, a team led by Anita Koushik, from the University of Montreal, looked at the link between eating fruits and vegetables and the risk for colon cancer. Koushik's team pored over data from 14 studies that included more than 756,000 men and women followed for between 6 to 20 years.

The report was published in the Sept. 25 issue of the Journal of the National Cancer Institute.

The researchers found that eating fruits and vegetables was not strongly associated with overall colon cancer risk.

However, among people who ate the largest quantities of fruits and vegetables, they did find a possible associated with a lower risk of cancer of the distal colon -- the left-hand side of the colon. But this association was not statistically significant, they noted.

"Results were consistent between men and women," Koushik's group added.

"The consumption of fruits and vegetables was not strongly associated with the risk of colon cancer overall but was inversely associated with the risk of distal colon cancer," they wrote. "Diets plentiful in fruits and vegetables remain important given these findings and the benefits that have been observed for other health outcomes, including cardiovascular disease and some other cancers," the team concluded.

McCullough agreed. "This finding doesn't change the bottom line," she said. "You should eat a diet high in a variety of fruits and vegetables," she said.

On the other hand, eating red and processed meat is associated with an increased risk for colon cancer, McCullough added.

More information

Get the American Cancer Society's recommendations on food and fitness  .

THURSDAY, Aug. 30 (HealthDay News) -- Many children today start specializing in one sport early -- playing year-round, joining competitive club or travel teams and participating in special training programs -- believing they'll put themselves on the fast track to college scholarships or maybe even a pro sports career.

But for too many of these kids, that fast track leads straight to injuries, sometimes serious ones.

Recent research suggests that as many as four in 10 emergency room visits for children between 5 and 14 years old are for sports-related injuries.

No single sport is specifically to blame for the increase in kids' sports injuries. Instead, experts suspect that choosing to play one sport all the time, or playing several sports all at once, are factors leading to what are called overuse injuries.

"Any sport can produce an overuse injury," explained Dr. Cynthia LaBella, medical director of the Institute for Sports Medicine at Children's Memorial Hospital in Chicago. "Overuse injuries are increasing for a couple of reasons. Sports are much more competitive at an earlier age, and many children are playing one sport year-round now. They're not getting enough time off for their bodies to recover. Or, they might be playing three sports at once, and what that amounts to is that they never get a day off."

While parents may counter that they were constantly active throughout their own childhoods and didn't suffer serious injuries, LaBella pointed out that youngsters used to be the masters of their own activity.

"Kids are now subject to adult schedules and organizational formats for adult-driven sports. In the past, kids directed the activities in the backyard. Where adults provide schedule and structure, kids may be pushed beyond what they would do on their own. When they play on their own, they take breaks and moderate themselves," she said.

Dr. Michael Kelly, chairman of the department of orthopaedic surgery at Hackensack University Medical Center in New Jersey, said that while it's a lot healthier for the body to "cross train" with different sports, many kids today focus on just one sport.

"It used to be that you played football and, when that was done, you might play basketball, and then later, you might play Little League or tennis. You went from sport to sport and didn't have any sport-specific training to contribute to repetitive injuries," Kelly said.

Children are particularly susceptible to repetitive injuries, because they're still growing. Both Kelly and LaBella said children are most vulnerable to injuries in the growth-plate areas. Growth plates are soft areas of developing tissue. They're found at the end of the long bones and, because these areas are still growing, the bone isn't completely calcified in that area.

According to the U.S. National Institutes of Health, growth-plate injuries are fractures, and they account for 15 percent of all childhood fractures. They occur twice as often in boys as in girls, with the greatest incidence among 14- to 16-year-old boys and 11- to 13-year-old girls.

So, does that mean parents shouldn't let their children play the sports they love? Not necessarily, said Kelly. But, parents do need to be willing to be the bad guy, especially if their child gets injured.

"Kids are always going to push, and they're always going to want to play. Even when hurt, a child probably won't make the right decision," said Kelly, adding that it's up to the parent to stop the child from playing if there's an injury.

Kelly acknowledged that that can be tough, particularly with high school-aged children who may have college scholarships riding on their ability to play. "I make it clear to parents that they can keep the next six months in mind, but they need to focus on the next 70 years," he said.

LaBella said children should never play through pain. "Pain is a sign of injury, and it's a sign that you need to rest," she said. If the pain doesn't get better after a couple of days, she advised that the child should go to the doctor.

Children also shouldn't start specializing in one sport until after puberty, according to LaBella, and, ideally, they should play just one sport per season and take off a month or two completely. That doesn't mean they should take two months off from all activity, she said, just from organized sports. "Go ride a bike or play soccer in the backyard," she suggested.

More information

To learn about preventing children's sports injuries, visit the Nemours Foundation  .