FRIDAY, Sept. 28 (HealthDay News) -- An Italian study has identified overweight as a direct cause of high blood pressure. And it also showed that up to half of overweight people can bring down blood pressure to healthy levels by weight reduction.

But the weight loss has to be achieved before the borderline to outright obesity is crossed, said Dr. Roberto Fogari, professor of medicine at the University of Pavia. He was to present the study findings Friday at the annual meeting of the American Heart Association's Council for High Blood Pressure Research, in Tucson, Ariz.

It's important that the study linked overweight to high blood pressure, which usually is described as "essential," a medical term meaning that the cause is unknown, Fogari said.

"The study suggests that, in many cases, hypertension [high blood pressure] is not essential," he said. "It is secondary to overweight. So, in the first stages of overweight, if we can induce people to reduce overweight, they can also avoid being treated for hypertension."

The study included 210 men and women whose body mass index [a ratio of weight to height] was between 25 and 29.9, indicating overweight but just short of the 30 mark of obesity. Their systolic blood pressure was between 140 and 159, and their diastolic pressure was between 90 and 99, indicating moderately high blood pressure.

An individualized low-calorie diet was designed for each study participant. Some also were prescribed orlistat, a drug that prevents fat from being metabolized.

After six months, 53 percent of the men and 49 percent of the women in the study achieved normal body weight, and a 5 percent reduction in blood pressure.

"The other 50 percent of those in the study already had abnormal changes in the vascular tree [blood vessel system], so that hypertension was no longer reversible by losing weight," Fogari said.

The implication for practicing physicians who see moderately overweight people with high blood pressure is that their first goal should be weight reduction, he said.

"Only after six months of trying to reduce the patient's weight can a decision be made about drug treatment," Fogari said.

Dr. Daniel W. Jones, dean of the University of Mississippi School of Medicine, and a spokesman for the American Heart Association, said the study finding "is not new news, but it is important news."

There have been a number of previous studies showing that weight loss can reduce blood pressure, Jones said. "But this is an increasingly important problem in societies around the world," he said. "Once you gain weight, you find it difficult to lose weight, which is why we focus so much on preventing obesity these days."

As for drug treatment of high blood pressure, about half of California adults diagnosed with hypertension do not take medication for it, another report presented at the same meeting found.

The study of 11,467 persons given a diagnosis of hypertension found that 49.4 percent were not taking drugs to reduce their blood pressure, said the report by researchers at the California Department of Public Health's Heart Disease and Stroke Prevention Program.

There were some bright spots in the picture. Compliance was more than five times higher for those who had seen a doctor in the past year than for those who had not. And the compliance rate was twice as high for persons with health insurance than the uninsured.

More information

For more on high blood pressure and what to do about it, turn to the American Heart Association  .

WEDNESDAY, Sept. 26 (HealthDay News) -- Very high doses of caffeine and acetaminophen (such as Tylenol), taken together, could lead to liver damage, researchers warn.

This combo produces a byproduct enzyme that's toxic to the organ, researchers from the University of Washington report.

This toxic twosome can occur not only by drinking caffeine while taking acetaminophen, the experts added, but also from large doses of painkillers that combine caffeine and acetaminophen. These painkillers are often used to treat migraines, menstrual discomfort and other conditions.

"Caffeine can interact with an enzyme that can form a toxic metabolite of acetaminophen in such a way that it increases the formation of that toxic metabolite," said lead researcher Sid Nelson, a professor of medicinal chemistry. "This can result in liver damage," he said.

In the study, Nelson's team tested the effects of acetaminophen and caffeine on E. coli bacteria. These bacteria had been genetically engineered to mimic a human enzyme in the liver that detoxifies many prescription and nonprescription drugs, explained the authors in a report in the Oct. 15 issue of the journal Chemical Research in Toxicology.

Nelson noted that it takes large qualities of caffeine to produce this reaction.

"Normally people wouldn't be ingesting that amount of caffeine," he said. "It would take 10 times the amount of caffeine found in a couple of cups of coffee," Nelson said.

His team found that caffeine triples the amount of a toxin called N-acetyl-p-benzoquinone imine (NAPQI) produced by the enzyme as it breaks down acetaminophen.

This same toxin is also produced during an interaction between alcohol and acetaminophen that's also well known to damage the liver.

In prior studies, Nelson's team had found that high doses of caffeine boosted liver damage in rats that had already suffered acetaminophen-linked liver damage.

The bacteria used in the study were exposed to doses of acetaminophen and caffeine far higher than most people would be exposed to, Nelson noted. It's not clear at what point such a mixture becomes toxic, he said.

Some people may be more vulnerable to this toxic interaction than others, Nelson said. They might include people who take certain antiepileptic medications, such as carbamazepine and phenobarbital, and people who use the alternative remedy St. John's Wort.

These drugs increase levels of the enzyme that produces NAPQI and may produce even more when mixed with acetaminophen and caffeine together, Nelson speculated.

In addition, because alcohol can boost NAPQI production, people who drink a lot may be at increased risk for this toxic interaction, the researcher said. The risk is also increased for people who take drugs that combine acetaminophen and caffeine, used to treat migraines, arthritis and other conditions.

Still, for most people, there's no reason to panic, since the chances of caffeine and acetaminophen becoming a toxic mixture remains small, Nelson said.

"Almost all people don't need to worry about taking caffeine with acetaminophen," Nelson said. Exceptions might be, " those [people] taking high does of caffeine, high doses of acetaminophen, who are possibly alcoholic and/or are epileptic and take certain anticonvulsive drugs," he said.

More information

For more on acetaminophen, visit the U.S. National Library of Medicine.

FRIDAY, Sept. 21 (HealthDay News) -- Diets high in quick-burning carbohydrates may cause fatty liver disease, which can lead to liver failure and death, according to a study in mice by researchers at Children's Hospital Boston.

If these findings are confirmed in humans, it may mean that fatty liver disease can be prevented and possibly treated through dietary changes, the study authors said.

They fed mice either a high- or low-glycemic index diet. The mice on the high-glycemic diet received a type of cornstarch that's digested quickly, while those on the low-glycemic diet received a cornstarch that's slowly digested.

In humans, examples of high-glycemic foods -- which raise blood sugar quickly -- include white bread, white rice, most prepared breakfast cereals and concentrated sugar. Vegetables, fruits, beans and unprocessed grains are examples of low-glycemic foods, which raise blood sugar slowly.

In this study, both groups of mice received equal amounts of total calories, fat, protein, and carbohydrate. After six months, both groups of mice weighed the same. However, the mice on the high-glycemic diet had twice the amount of fat in their bodies, blood and livers than those on the low-glycemic diet.

The findings were published in the September issue of the journal Obesity.

"Our experiment creates a very strong argument that a high-glycemic index diet causes, and a low-glycemic diet prevents, fatty liver in humans," research leader Dr. David Ludwig, director of the Optimal Weight for Life program at Children's Hospital Boston, said in a prepared statement.

He and his colleagues have just launched a clinical trial to examine whether a low-glycemic index diet can reverse fatty liver in overweight children.

More information

The American Liver Foundation has more about fatty liver  .

MONDAY, Sept. 10 (HealthDay News) -- U.S. and Canadian experts have teamed up to create Dietary Fatty Acids, a comprehensive recommendation on how much of what types of fats people should include -- or avoid -- in their diets.

Both the American Dietetic Association and the Dietitians of Canada agree that the body needs some fat and that 20 percent to 30 percent of energy needs should be met by dietary fat. The key question is which kind of fats are most healthy.

"Of greatest importance is the type of fat one chooses," registered dietitian and co-author Penny Kris-Etherton said in a prepared statement. "The healthiest choices are unsaturated fats found in liquid vegetable oils, nuts and seeds, and omega-3 unsaturated fats found in fatty fish such as salmon, sardines and shellfish."

She warned against saturated fats and trans fats. Saturated fats are found in tropical oils, fatty meats and high-fat dairy products. Trans fats are found in commercial baked goods, crackers and high-fat snack foods. Consumers should read nutrition labels to find out what kinds of fats are in the foods they buy, said Kris-Etherton.

The Dietary Fatty Acids recommendations guide people to follow a food-based approach for achieving the following fatty acid recommendations:

• Eat lots of vegetables and fruits, whole grains, legumes, nuts and seeds.
• Eat lean protein such as meats, poultry and low-fat dairy products.
• Eat fish, especially those high in omega-3 fatty acids such as salmon.
• Use non-hydrogenated margarines and oils.

More information

For a consumer-friendly fact sheet on dietary fats, visit the Dietitians of Canada.