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FRIDAY, Jan. 5 (HealthDay News) -- Millions of Americans take popular drugs to lose weight, but the long-term risks and benefits of these medications aren't known, two Canadian researchers contend.

Drs. Raj Padwal and Sumit Majumdar, of the University of Alberta, said long-term studies are needed to determine whether losing weight on drugs such as sibutramine (Meridia), orlistat (Xenical) and rimonabant (Acomplia) actually reduces the risks of heart attack, stroke and diabetes associated with being overweight or obese.

The physicians expressed their views in the Jan. 6 issue of The Lancet.

"These three medications will likely lower weight, modestly, but we need better studies," Padwal said. "The studies that are out there don't provide information on cardiovascular disease and cardiovascular deaths. The other problem is that they are not long-term and have high dropout rates. We really need to know what the net benefits of these medications are, and truly know whether we should be using them or not."

Padwal and Majumdar reviewed all the published studies on the risks and benefits of the drugs.

For example, Meridia is associated with improvement in some cardiovascular risk factors, but for some patients it raises blood pressure, Padwal said.

"If you are going to prescribe a weight-loss drug, the ultimate goal is not a cosmetic one. The ultimate goal is to get that person to be healthier and lower their risk of having cardiovascular problems," Padwal said. "If you are going to give a medication that raises the blood pressure, then you have to question, is the net benefit advantageous or am I putting this patient at increased risk."

Padwal noted that studies are now under way to determine the long-term benefits and risks of these drugs. But such studies take time, and drugs such as Merida and Xenical have been on the market for several years. "That's going to be eight to nine years of using the medication before we finally get more definitive evidence whether they are beneficial or not," he said.

The ultimate question, Padwal said, is whether the modest weight loss associated with these drugs is really a benefit for overall health. People who exercise may only lose a little weight but they can significantly reduce their risk of heart attack and stroke and diabetes, he noted.

"Until you have a study that shows that these medications lower the incidence of heart attack, the incidence of stroke, cardiovascular mortality, overall mortality, you don't know what the overall net benefit of these medications are," Padwal said.

One expert doesn't think drugs are the solution to the obesity epidemic gripping the United States and many other developed nations.

"To date, the history of weight-loss drugs is not very encouraging," said Dr. David L. Katz, an associate professor of public health and director of the Prevention Research Center at Yale University School of Medicine. "The two FDA-approved weight-loss drugs now available, sibutramine and orlistat, have serious potential side effects, limited efficacy, and work only as long as they are taken."

Rimonabant, a new drug soon to be available, blocks a receptor influencing appetite, and looks promising. But studies suggest its effects may wear off over time, and side effects are unknown, Katz said.

"Obesity is less about the body doing anything wrong than it is about an environment that is all wrong for our bodies," he said. "We are adapted to survive in a world where calories are scarce and physical activity demands high. To use pharmacotherapy to fight obesity, we are, in essence, hoping to redirect the fundamental activities of human metabolism. I don't think we'll ever succeed in doing so, without dire cost in toxicity and side effects."

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases can tell you more about weight loss.

WEDNESDAY, Jan. 3 (HealthDay News) -- Age-related hearing loss, a common problem among the elderly, might be related to inadequate levels of folic acid, European researchers report.

The researchers found that people who took a folic acid supplement had less decline in hearing low-frequency sounds over time, compared with people who didn't take the supplement.

Results of the study, led by Jane Durga, of the Cognitive Sciences Group, Nutrition & Health Department at the Nestle Research Center in Lausanne, Switzerland, are published in the Jan. 2 issue of the Annals of Internal Medicine.

The researchers randomly assigned 728 older Dutch men and women, who showed signs of age-related hearing loss and low folate levels, to receive either 800 grams of a folic acid supplement or a placebo daily for three years.

Durga's team chose to conduct the study in the Netherlands because, unlike the United States, the Netherlands does not fortify its food with folic acid, a B vitamin also known as folate. Folate levels in study participants were about half those found in Americans. In the United States, many foods contain supplemental folic acid because of its benefits in protecting against birth defects.

At the end of the trial, the researchers found that the ability to hear low-frequency sound did not decrease significantly among those taking folic acid supplements. However, there was no slowing in the decline in hearing high frequencies in either group.

The thresholds of the low frequencies increased by 1.0 decibel in the folic acid group and by 1.7 decibels in the placebo group, the researchers said.

"Folic acid supplementation slowed the decline in hearing of the speech frequencies associated with aging in a population from a country without folic acid fortification of food," the researchers wrote. "The effect requires confirmation, especially in populations from countries with folic acid fortification programs."

But Robert W. Sweetow, director of audiology at the University of California, San Francisco, Medical Center, called the results "clinically insignificant."

"I think that their conclusion that folic acid is actually slowing down the progression of age-related hearing loss is a stretch," Sweetow said. "I would hate to say to patients, 'You take folic acid and the progression of your hearing loss is going to slow down.'"

Another expert questioned the significance of the finding.

"The effect is on low frequency hearing, but most older folks have a problem with high frequency hearing," said Dr. Hinrich Staecker, an associate professor in the department of otolaryngology-head & neck surgery at the University of Kansas Medical Center.

Staecker also noted that the study authors didn't look at the ability of the participants to hear speech clearly. "It's easier to make stuff louder, but it's not easy to make stuff clearer," he said.

Dr. Peter M. Rabinowitz, an associate professor of medicine at the Yale University School of Medicine, said, "The investigators' finding that low-frequency, but not high frequency, hearing loss was reduced in the folate supplementation group is somewhat surprising, since age-related hearing loss usually affects the higher frequencies of hearing first and to a greater degree."

Clearly, much is not known about nutrition and hearing, Rabinowitz said. For example, other studies have suggested that genetic differences in the metabolism of folate may affect how someone responds to supplementation, including the effect of folate on hearing loss, he said.

"While neither this study nor the current state of medical knowledge provide adequate evidence for recommending particular supplements to prevent hearing loss, this study provides additional evidence of the importance of adequate nutrition in older adults, as well as the potential for future discoveries of how to slow the aging process of the hearing system," Rabinowitz said.

More information

The U.S. Food and Drug Administration can tell you more about age-related hearing loss.

WEDNESDAY, Jan. 3 (HealthDay News) -- Researchers from the Yale University School of Medicine have uncovered a complex series of events in the brain that stimulate hunger during fasting.

A study published in the January issue of Cell Metabolism found that during periods of fasting, a cascade of events in the brain makes sure you stay hungry when food is scarce.

The researchers revealed that thyroid hormone in the brain is associated with increases in an "uncoupling" protein known as UCP2, which boosts the number of power-generating mitochondria in neurons that drive hunger.

When mice were fasted for 24 hours, the researchers found there was an increase in the enzyme that stimulates thyroid hormone production in concert with increased UCP2 activity.

The UCP2 activation resulted in a proliferation of mitochondria in the neurons, which increased the brain cells' excitability and resulted in "rebound feeding" in the mice after a period of food deprivation.

The mice that lacked either UCP2 or the thyroid-stimulating enzyme ate less than normal after they were fasted.

"This shows the key importance of UCP in the brain and its effect on neuronal activity," lead researcher Sabrina Diano said in a prepared statement. "It's how neurons 'learn' that food is missing, and it keeps them ready to eat when food is introduced."

More information

The American Thyroid Association has more about thyroid and weight  .

THURSDAY, Dec. 28 (HealthDay News) -- A large majority of Americans say they support changes in public policy to stem the rising tide of obesity among adults, a new survey shows.

"There is a lot of support for employer and health policies aimed at preventing obesity," said lead researcher Bernard Fuemmeler, an assistant professor in the department of community and family medicine at Duke University Medical Center, in Durham, N.C.

"This study provides tangible evidence that people support wide-scale policy changes that can affect obesity in the U.S.," Fuemmeler added.

The findings appear in the January issue of the American Journal of Preventive Medicine.

Approximately 60 million American adults are obese, according to the U.S. Centers for Disease Control and Prevention. In 1998, Americans spent about 9 percent of all medical expenses on problems linked to being overweight or obese, the CDC reports.

The new telephone survey of 1,139 adults found that 85 percent supported tax breaks for employers who made exercise space available to employees.

In addition, 73 percent said they'd support government incentives for companies that reduced the cost of health insurance for employees who had healthy lifestyles and shed extra pounds. Seventy-two percent said they would support government policies requiring insurance companies to cover obesity treatment and prevention programs.

"There is growing public advocacy for these kinds of policy changes," Fuemmeler said. "There is also advocacy in the research community for large-scale policy changes. With some push, we might be able to get some changes that would help us better address the obesity epidemic in the country."

But one expert said it will take more than policy changes to get Americans to eat better and exercise more.

"The problem is not necessarily that employers need tax incentives," said Kathryn M. Kolasa, a professor in the department of nutrition services and patient education at East Carolina University. "The employer can expect to realize health-care cost savings and can be motivated by that."

However, "It's not clear what will motivate the employees," Kolasa said.

One problem is misinformation about weight loss. "Most individuals that present for nutrition counseling have significant amounts of misinformation about food and beverages that prevent them from being successful in weight loss or weight management," Kolasa said.

"Also, people continue to say that it costs more money to eat healthy, when it has been demonstrated time and again you can eat healthy at no greater cost," Kolasa added.

She does believe that changes in policy might make it easier for people to take advantage of health-promotion programs.

"Just because an insurance company provides a wellness benefit doesn't mean people will use it," Kolasa said. "I have one patient who was excited to receive the wellness benefit -- six visits with a certified dietitian during the year. Her employer let her take time from work for the first visit, but said subsequent visits would have to be on her time. This same employer allows employees to take time for doctor visits without penalty," she said.

More information

For more on obesity and weight loss, head to the U.S. Centers for Disease Control and Prevention.