TUESDAY, Oct. 16 (HealthDay News) -- Garlic lovers, take heart: The pungent root may promote healthier responses in blood vessels.

So say researchers who found that compounds in garlic cause tissues or blood vessels to release a chemical called hydrogen sulfide. In large quantities, this compound can be deadly, but it's also an essential molecule within the body, causing blood vessels to relax and reducing dangerous inflammation.

But how you take your garlic matters, the research showed. "If you prepare it in certain ways, you can lose the compounds that cause it to release hydrogen sulfide, so that helps explain why there has been such great variability in studies," noted senior researcher David Kraus, an associate professor of environmental health sciences at the University of Alabama, Birmingham.

His team published its findings in this week's online edition of the Proceedings of the National Academy of Sciences.

In the array of garlic health studies, more than half have shown some positive effect, but that effect has tended to be small, and some trials have even shown negative health effects, Kraus noted. Some of his team's experiments used juice extracted from supermarket garlic. Human red blood cells exposed to tiny amounts of the juice began emitting hydrogen sulfide. Most hydrogen sulfide production took place at the membrane of the red blood cells, although a fraction was made within the cells.

When working with garlic, Kraus first crushes the clove. He then waits for the reaction that produces the compounds that trigger hydrogen sulfide release. "We usually let the garlic crush for 15 minutes," he said.

Other studies of garlic's health effects have failed, Kraus said, because they look for activity that is impossible -- a reduction in blood cholesterol levels, for example. One such trial was done by Christopher D. Gardner, a nutrition scientist and assistant professor at Stanford University's Prevention Research Center in California.

"We used real raw garlic and two commercial supplements in doses higher than people are advised to take," Gardner noted. "We assumed that at least one of the three would work. These were people whose LDL ['bad'] cholesterol was elevated. We worked with 192 people for six months, and they [LDL cholesterol levels] didn't budge, not even a bit, month after month."

According to Gardner, Kraus' work now offers a reason for that failure, because hydrogen sulfide has no effect on cholesterol.

Another expert urged caution in interpreting the Birmingham team's results.

Eric Block, professor of chemistry at the State University of New York, Albany, has also done extensive work on garlic. He called the paper "provocative" but expressed some concerns.

For example, he said, "the benefits of garlic on cardiovascular disease remain controversial, because they have not been established by the gold standard method of placebo-controlled, double-blind clinical studies," he said.

It's also uncertain that garlic's purported beneficial effects are due to the mechanism described in the new report, Block added. Clinical trials are needed to help prove that point, he said.

According to Block, Kraus' team, "should be more conservative in over-extending some of their conclusions in the absence of additional work." However, "their work does represent a significant advance in the science of this amazing, ancient, ever-popular herb," he said.

Kraus stressed that his study only looked at the effect of fresh garlic, not garlic supplements. "What we are proposing is that you eat a garlic-rich diet," he said. "We haven't really tried to look at supplements yet."

"Garlic-rich" has different meanings, depending on the part of the world being studied, Kraus added. "In the Middle East, that would be 5 to 10 cloves of garlic a day," he said. "If you go to the Far East, it would be even higher."

More information

There's more on garlic and health at the U.S. National Center for Complementary and Alternative Medicine.

THURSDAY, Oct. 11 (HealthDay News) -- In the last week:

• Topps, which billed itself as the leading U.S. maker of frozen hamburger patties, declared bankruptcy after the company recalled 22 million pounds of beef due to E. coli contamination.
• Sam's Club issued a nationwide recall of 840,000 pounds of a brand of beef patties believed to be responsible for four cases of E. coli poisoning.
• ConAgra Foods asked stores to remove its popular Banquet Chicken and Turkey pot pies after they were linked to at least 139 cases of salmonella in 39 states.
• 145 cases of food poisoning were reported in the United States.

A coincidence? Or is there a larger -- and worrisome -- problem with food safety in the United States?

Experts say the events of the last week owe to a combination of heightened public attention as well as significant flaws in the nation's food-safety system, including both production and oversight.

"This is just all an indication of the problems we have in the system," said Michael Hansen, a senior scientist at Consumers Union. "There's a heightened awareness about it, because the media is picking up on things. The [U.S. Centers for Disease Control and Prevention] data shows an uptick of food-poisoning cases. And, in a heightened environment of attention, the government acts more."

These problems are just the latest in a long line of mishaps. For example, ConAgra, which made the questionable pot pies, also made the peanut butter tainted with salmonella that sickened 625 people in 47 states earlier this year.

What's going wrong?

For one thing, it's likely that given the current environment of heightened sensitivity to food safety, consumers -- and patients -- are connecting the dots more frequently.

"I think with the media attention over the past couple of years, people are more careful when they go to physicians to make a connection between some event, especially when they have a gastrointestinal-type disorder, and physicians are quicker to make a connection," said Dr. Philip Tierno, director of clinical microbiology and immunology at New York University Medical Center.

But part of the problem is also the food production and distribution system.

Any one beef patty will contain meat from several different animals. "One contaminated animal can screw up a big batch of ground beef," said Dr. Helene Andrews-Polymenis, assistant professor of microbial and molecular pathogenesis at Texas A&M Health Science Center College of Medicine.

And it's not that easy to spot which animals really are sick, because those carrying potentially harmful germs in their intestines don't have any symptoms, Andrews-Polymenis said.

"Obviously sick animals get removed from the slaughterhouse, but these animals aren't sick," she said. "We have to find better ways to figure out what's going on. One of the ways is doing basic microbial testing on carcasses. The more public money spent on research and food-safety issues, the less we're going to have these problems."

Hansen added that supplies of meat used for hamburger patties will often be used from one day to the next. If it's not kept under strict conditions, it's a recipe for growing bacteria.

Then there's the larger issue of the industrialization and centralization of the nation's food system.

"The [2006] spinach recall was Natural Selection foods. They packed spinach for how many different brands? Dozens and dozens," said Hansen. "When you start concentrating things, a little problem can become quite a big one."

Globalization of food production also plays a part. "We're getting products from all over the world more frequently now than ever before," said Tierno, author of The Secret Life of Germs and Protect Yourself Against Bioterrorism. "The diarrheal disease in the Third World experienced last week may visit your house tomorrow."

Combine these trends with regulatory shortcomings, and the problems are magnified. Experts such as Hansen say there aren't enough inspections of food plants in general. And that's because there aren't enough government inspectors to go around.

In fact, inadequate inspections are just one of a number of problems plaguing the government's food-safety system, experts say.

Another problem is the lack of a mandatory recall authority. All product recalls are voluntary on the part of the company. "The government not having mandatory recall authority is just absurd," Hansen said.

Some have proposed that a centralized food "czar" be put in control of all food-safety issues, rather than the current fragmented system, which is divided unequally -- and many say inequitably -- between the U.S. Food and Drug Administration and the U.S. Department of Agriculture.

"They had been talking about making this a cabinet-level position," Tierno said.

Obviously, much of the burden for remedy lies with big business and the government, but there are things consumers can do.

"Consumers can cook things to higher temperatures if they're concerned about killing bacteria," Hansen said.

Also, be careful not to cross-contaminate surfaces. If you've chopped a chicken on a cutting board, clean the board and the knife before using it on salad or vegetables.

"People can focus on things more locally and go to farmer's markets or join a CSA [Community Supported Agriculture]," Hansen said.

More information

Visit the U.S. Centers for Disease Control and Prevention for more on food safety.

FRIDAY, Oct. 5 (HealthDay News) -- Not all diet plans are equally heart-healthy, according to a study ranking eight popular weight-loss programs.

Diets that emphasize a variety of fruits and vegetables scored better than those with a heavy protein focus.

The Ornish diet plan came out on top with the most potential to prevent heart disease risk factors. The Atkins diet came in last, lagging behind the Zone and Weight Watchers.

"It was not surprising to me that the Ornish diet came out on top given that the index used is designed to measure dietary components related to risk of heart disease," said dietician Lona Sandon, a national spokeswoman for the American Dietetic Association.

Sandon said the take-home message for consumers is "if heart disease is your concern, you need to focus more on fruits, vegetables and make all your grains whole grains, as well as limit intake of animal foods and fats."

The findings are published in the October issue of the Journal of the American Dietetic Association.

Researchers at the University of Massachusetts Medical School ranked daily meal plans and food recommendations in the Ornish Plan, the Zone Diet, Atkins, two Weight Watchers plans, the South Beach Diet, the New Glucose Revolution and the 2005 MyPyramid plan.

The rankings were based on the Alternate Healthy Eating Index (AHEI), which uses the daily dietary intake of fruits, vegetables, fats, fiber, nuts, soy and white meats instead of red meat to determine how much benefit a diet has for heart health.

The highest possible score is 70. While none of the diets had a perfect score, they varied across a 20-point spread:

• Ornish, 64.6.
• Weight Watchers high-carbohydrate, 57.4.
• New Glucose Revolution, 57.2.
• South Beach Phase 2, 50.7.
• Zone, 49.8.
• MyPyramid, 48.7.
• Weight Watchers high protein, 47.3.
• Atkins 100-g carbohydrate, 46.
• South Beach Phase 3, 45.6.
• Atkins 45-g carbohydrate, 42.3.

Study author and clinical psychologist Sherry Pagoto said there's no cut-off point in the AHEI scale below which a diet could be definitively considered heart unhealthy. But other studies have ranked low-quality diets in populations at risk for heart disease around the 30-point mark.

"We were most surprised by the fact that the MyPyramid wasn't even in the top three. We figured that this would be a model diet because it is based on the U.S. Department of Agriculture dietary recommendations," Pagoto said.

However, coming in last doesn't mean a diet is of low quality, she said. All of the diets have the potential to be healthy and have been shown in a variety of studies to result in weight loss, which is itself important to improving heart health. Additionally, coming in first does not mean the diet plan is ideal for everyone, she added.

"While the Ornish plan was on top, it's a hard one for most people to follow," Pagoto said. The Ornish plan is a very low-fat, low-calorie, primarily vegetarian diet developed for people who have survived heart attacks, she explained.

In her work counseling clients at the University of Massachusetts Memorial Weight Center, Pagoto said she has learned that it's important for people to be able to stick to the diet plan they choose.

"There is more than one element of a diet to consider," she said.

People with a personal or family history of heart disease should consider the results of this study as a guide when choosing a diet plan, Pagoto said. But they should also think about their food preferences. For example, people who really like carbohydrates would do better with Weight Watchers than with Atkins, regardless of this ranking system, she said.

Pagoto advises patients to keep a food log over several weeks to get a better idea of their food preferences and calorie intake before starting a diet.

Lack of variety courts diet disaster due to boredom, Pagoto said. People will eventually get tired of the limitations of a tightly controlled or hard-to-implement diet, she said.

Despite not making the top three, the USDA's MyPyramid allows for the most variety, she said.

Sandon said: "What I find in working with clients is that most people tend to eat the same foods on a daily or weekly basis and have little variety. They do not want to have to seek out special foods or learn to prepare new foods they are not familiar with. In general, I find that many people in the initial phase of starting a weight-loss plan are more comfortable sticking to a plan of the same foods most of the time but want permission to have something different here and there."

A second study in the same issue of the journal suggests that using canola-based products instead of other oils all the time could meet national standards for healthy fats. Canola oil can help decrease adults' saturated fatty acid intake by up to 9.4 percent and increase their intake of monounsaturated fatty acids by 27.6 percent. Alpha-linolenic acid intake would increase 73 percent. The switch would not affect total calories, fat and cholesterol, according to the researchers, from the University of Illinois and Pennsylvania State University, who studied the diets of more than 9,000 people.

More information

For more about the USDA's dietary guidelines, visit MyPyramid.

TUESDAY, Oct. 2 (HealthDay News) -- Exercise that boosts cardiovascular health may also help keep knee cartilage healthy and protect against knee osteoarthritis, Australian researchers say.

Previous studies on the issue have produced conflicting findings, the team said. Some studies concluded that exercise may trigger knee osteoarthritis, while other studies found that exercise may protect the knees from osteoarthritis.

In this new study, researchers analyzed the effect that varying levels of intensity, frequency and duration of exercise had on the knees of 257 healthy adults, ages 50 to 79, with no history of knee osteoarthritis.

Reporting in the October issue of Arthritis Care & Research, the team found an association between physical activity and good knee health. For example, vigorous activity was linked with healthier cartilage and moderate exercise, including regular walking, was associated with lower incidence of bone marrow lesions.

"This is the first study to demonstrate a potentially beneficial effect of walking on the reduction in the risk of bone marrow lesions in the knee," Dr. Flavia M. Cicuttini, leader of the Melbourne Collaborative Cohort Study, said in a prepared statement. "Bone marrow lesions have been associated with pain and radiograph-defined progression of osteoarthritis, type II collagen degradation, and loss of cartilage volume," she added.

Both exercise intensity and duration had a major positive impact on knee cartilage, but it's not clear what amount of exercise is ideal for joint health, the group said.

"Our data suggest that at least 20 minutes once per week of activity sufficient to result in sweating or some shortness of breath might be adequate. This is similar to, if not somewhat less than, the recommendations for cardiovascular health," Cicuttini said.

More information

The American Academy of Family Physicians has more about knee OA  .