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Short bouts of exercise can go a long way to reduce the impact stress has on cell aging, new research reveals.

Vigorous physical activity amounting to as little as 14 minutes daily, three day per week would suffice for the protective effect to kick in, according to findings published online in the May 26 issue of PLoS ONE.

The apparent benefit reflects exercise’s effect on the length of tiny pieces of DNA known as telomeres. These telomeres operate, in effect, like molecular shoelace tips that hold everything together to keep genes and chromosomes stable.

Researchers believe that telomeres tend to shorten over time in reaction to stress, leading to a rising risk for heart disease, diabetes and even death. However, exercise, it seems, might slow down or even halt this shortening process.

“Telomere length is increasingly considered a biological marker of the accumulated wear-and-tear of living, integrating genetic influences, lifestyle behaviors and stress,” study co-author Elissa Epel, an associate professor in the University of California San Francisco (UCSF) department of psychiatry, said in a news release. “Even a moderate amount of vigorous exercise appears to provide a critical amount of protection for the telomeres.”

Appreciation for how telomeres function and how stress might affect their length stems from previous Nobel-prize winning work conducted by UCSF researchers. Prior studies have also suggested that exercise is in some way associated with longer telomere length.

The current effort, however, is the first to identify exercise as a potential “stress-buffer” that can actually stop telomeres from shortening in the first place.

To identify this link, Epel and her co-authors focused on 62 postmenopausal women, and asked them to log how many minutes of vigorous physical activity — namely activity that increased their heart rate or induced sweating — they had completed every day over three days. Perceptions of stress were also solicited, and the researchers took blood samples to determine telomere length.

The team found that those women who were experiencing high levels of stress but were deemed “active” did not have shorter telomeres, whereas similarly stressed participants deemed “inactive” did.

Going forward, the study authors said that more research incorporating larger patient samples need to be conducted to confirm the findings and arrive at definitive recommendations for how much exercise might be needed to derive such cellular protection.

SOURCE: PLoS ONE, news release.

Visits to U.S. hospital emergency departments related to underage drinking rise by 11 percent over the Memorial Day weekend versus other days, a new report finds.

The Drug Abuse Warning Network (DAWN) report also found that people under age 21 who combine alcohol and illegal drugs are 27 percent more likely to visit hospital emergency rooms over the Memorial Day holiday weekend compared to an average day. On an average, there are 199 such visits per day during the holiday weekend vs. 156 visits on other days, the report said.

The DAWN report was developed by the Substance Abuse and Mental Health Services Administration (SAMHSA).

“Underage drinking poses an enormous public health risk — approximately 5,000 people die each year from alcohol-related injuries connected to underage drinking,” SAMHSA administrator Pamela S. Hyde said in an agency news release. “Moreover, studies have shown that children who begin drinking before age 15 are six times more likely to develop alcohol problems than people who start drinking after they reach age 21.”

The SAMSHA report is based on statistics from 2008.

SOURCE: Substance Abuse and Mental Health Services Administration, press release.

If milk does the heart good, it might do the heart better if it comes from dairy cows grazed on grass instead of on feedlots, according to a new study.

Earlier experiments have shown that cows on a diet of fresh grass produce milk with five times as much of an unsaturated fat called conjugated linoleic acid (CLA) than do cows fed processed grains. Studies in animals have suggested that CLAs can protect the heart, and help in weight loss.

Hannia Campos of the Harvard School of Public Health in Boston and her colleagues found, in a study of 4,000 people, that people with the highest concentrations of CLAs — the top fifth among all participants — had a 36 percent lower risk of heart attack compared to those with the lowest concentrations.

Those findings held true even once the researchers took into account heart disease risk factors such as high blood pressure and smoking.

The new findings suggest that CLA offers heart-healthy benefits that could more than offset the harms of saturated fat in milk, Campos said.

“Because pasture grazing leads to higher CLA in milk, and it is the natural feed for cattle, it seems like more emphasis should be given to this type of feeding,” she told Reuters Health by email.

Dairy products in the U.S. come almost exclusively from feedlots, she added. And cow’s milk is the primary source of CLA. (Beef contains a small amount.)

Campos and her colleagues looked to Costa Rica for their study, where pasture grazing of dairy cows is still the norm. They identified nearly 2,000 Costa Ricans who had suffered a non-fatal heart attack, and another 2,000 who had not. Then they measured the amount of CLA in fat tissues to estimate each person’s intake.

Since CLA typically travels with a host of other fats, the researchers went a step further to tease apart its effects from those of its predominantly unhealthful companions, they report in the American Journal of Clinical Nutrition. The difference in risk attributed to CLA subsequently rose to 49 percent.

“Whole-fat milk and dairy products have gotten such a bad reputation in recent years due to their saturated fat and cholesterol contents, and now we find that CLA may be incredibly health-promoting,” Michelle McGuire, spokesperson for the journal’s publisher, the American Society for Nutrition, and associate professor at Washington State University, told Reuters Health in an email. “Whole milk is not the villain!”

Each year, approximately 1.5 million Americans will suffer a heart attack. A third will not survive.

The evidence may now be piling up: another paper out of Sweden in the same issue of the journal as the Costa Rican study also hints at heart attack protection through milk fat.

Further, the benefits of CLA may extend beyond the heart to the prevention of cancer and diabetes, suggests McGuire, pointing to results of other animal studies. “Milk is actually the only food ever ‘designed by nature’ to be fed to mammals,” she added. “We need to look to milk as the perfect food and learn everything we can from it.”

SOURCE: http://www.ajcn.org/cgi/content/abstract/ajcn.2010.29524v1 American Journal of Clinical Nutrition.

There’s good news for fat people who are nearing middle age: A new study finds that judged by medication use alone, 25-to-39-year-olds who are classified as obese aren’t more likely to suffer illness than people of normal weight.

So, should you put on the extra pounds with no worries? Not exactly, since being obese at a young age can still raise the risk of health problems later in life.

The researchers examined data on medication usage from a national survey from 1988-1994, 2003-2004 and 2005-2006. A total of 9,071 women and 8,880 men aged 25 to 70 were included.

The research team ruled out drugs used to treat mental illnesses or medications not associated with physical illnesses.

The study examined statistics about body-mass index, a number that measures whether a person’s weight and height are proportional.

“For college-age adults, this should help them realize that they don’t have to worry so much if they have a BMI of 27 or 28. Some young people with these BMIs feel like, ‘I’m going to have all these problems, I need to try 50 different diets.’ And what is all that stress and dieting doing to your body? Probably more damage than the extra 15 pounds is,” study author Brant Jarrett, a doctoral student in neuroscience at Ohio State University, said in a news release from the school.

A limitation of the study is that it determined health based only on the medications that people were taking, so some youth could have had undiagnosed medical problems or diseases.

The findings appear online in the International Journal of Obesity.

Researchers at the U.S. National Institutes of Health have discovered bone-generating stem cells in the spine, at the end of the shins and in cartilage-rich areas of other bones.

They also identified factors that control the growth of these stem cells, according to a report published online April 26 in the Proceedings of the National Academy of Sciences.

Eventually, it may be possible to use these newly identified bone stromal cells to repair damaged or malformed bone, the researchers suggested. They pinpointed the new stem cells in adult mice.

“Identifying the location of bone stem cells and some of the genetic triggers that control their growth is an important step forward,” Dr. Alan E. Guttmacher, acting director of the U.S. National Institute of Child Health and Human Development, said in an agency news release. “Now researchers can explore ways to harness these cells so that ultimately they might be used to repair damaged or malformed bone.”

Studies of the newly found stem cell population, he added, could yield insight into the formation of bone tumors. Much of the research was conducted at the institute.

SOURCE: U.S. National Institute of Child Health and Human Development, news release.

Adding a computed tomography test to measure calcium in coronary arteries improves predictions of future heart disease, a new study finds, but no one knows yet whether it’s worth the cost and risk due to radiation exposure.

“This kind of evidence gives encouragement to go on and do additional testing, but it shouldn’t convince us that this test should be done routinely,” said Dr. Philip Greenland, a professor of preventive medicine at Northwestern University Feinberg School of Medicine, and a member of the team reporting the study in the April 28 issue of the Journal of the American Medical Association.

Computed tomography uses X-rays to get a detailed picture of heart structure. Its use in diagnosing existing heart disease has become controversial because X-ray exposure increases the risk of cancer. The new study of nearly 6,000 healthy Americans was done to see whether the technique could improve the predictive power of existing cardiac risk factors such as high blood pressure, high cholesterol and obesity.

The study began in July 2000 and ran through May 2008. It used two models to predict the five-year risk of a heart attack, resuscitated cardiac arrest or death from coronary heart disease: the traditional risk factors; or those risk factors plus the coronary artery calcium score.

At 5.8 years, the participants had experienced 209 coronary heart disease problems and 122 “major events” — that is, heart attacks, deaths from coronary heart disease, or cardiac arrest followed by a resuscitation.

The second model, which used the regular risk factors plus the calcium scan, was able to predict an additional 23 percent of the participants who would go on to experience a harmful cardiovascular event. In addition, 13 percent the model reclassified as low-risk did not experience an adverse event.

But does that added predictive power make a difference in terms of saving lives and reducing unnecessary treatment?

“We didn’t look at that,” Greenland said. “What we can say here is that additional testing looks like it improves prediction. Whether it improves clinical outcome requires a different kind of study.”

The first steps toward such a study have been taken. “We are in discussions with the National Heart, Lung, and Blood Institute and have been encouraged to submit a proposal,” Greenland said.

Such a study might involve tens of thousands of participants and cost over $100 million, said Dr. Andrew J. Einstein, director of cardiac computed tomography research at Columbia University Medical Center in New York City.

The study would aim at determining whether more intensive treatment of traditional risk factors would improve survival of people classified as high-risk by the coronary artery calcium score. “No study has compared patients who had intensive preventive therapy with those who didn’t and see if it makes a difference in terms of the number of heart attacks people have,” Einstein said. “That study would be the ideal.”

Such a trial needn’t be as expensive as Einstein estimates, Greenland said. He puts the cost at “between $29 million and $50 million” and notes that the U.S. Institute of Medicine lists that kind of trial among the top 100 that should be done using funds provided for comparative effectiveness research in the newly approved health care program.

Cancer risk and cost are also parts of the equation. A well-controlled computed tomography scan gives about twice the radiation exposure as a mammogram, Greenland said. A new large-scale trial could show whether the added risk is justified by the number of lives saved, and the same is true of the cost, estimated to run between $200 and $600 per scan.

“Concern about radiation for any individual is minimal, and the cancer issue is 20 years down the line,” said Dr. Joseph Ladapo, a clinical fellow in medicine at Harvard Medical School and Beth Israel Deaconess Medical Center in Boston. Incidental findings of a scan, such as possible lung problems, can also help justify its widespread use, Ladapo said.

But the time for widespread use has not arrived, Greenland noted. The new study results “are not an endorsement for screening,” he said.

SOURCES: Philip Greenland, M.D., professor, preventive medicine, Northwestern University Feinberg School of Medicine, Chicago; Andrew J. Einstein, M.D., Ph.D., assistant professor, clinical medicine, director, cardiac computed tomography research, Columbia University Medical Center, New York City; Joseph Ladapo, M.D., Ph.D., clinical fellow, medicine, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston;

Eating a Mediterranean diet may help keep your brain healthy as you age, findings from an ongoing study show.

“This diet emphasizes vegetables, fruits, fish, olive oil, lower meat consumption, and moderate wine and non-refined grain intake,” study author Dr. Christy Tangney, of Rush University Medical Center in Chicago, said in a news release from the American Society for Nutrition.

Rather than asking people to avoid certain foods, the study found data that “adults over age 65 should look to include more olive oil, legumes, nuts, and seeds in their diet in order to improve their recall times and other cognitive skills, such as identifying symbols and numbers,” Tangney said.

The study included 4,000 adults aged 65 and older who were given a series of tests to examine their cognitive (or thinking) skills every three years over a 15-year period. Those who scored highest in following a Mediterranean diet were least likely to suffer cognitive decline, the study authors found.

“We [also] want older adults to remember that physical activity is an important part of maintaining cognitive skills,” Tangney added.

The findings were slated to be presented Monday at the Experimental Biology 2010 meeting in Anaheim, Calif.

SOURCE: American Society for Nutrition, news release.

A mutation that affects how the body responds when a person smells or tastes food may play a role in the development of type 2 diabetes in some people, U.S. researchers report.

“Our study showed there is a novel genetic mutation through which some type 2 diabetic people could be vulnerable to the gradual onset of this disease,” study senior author Vann Bennett, a professor in the departments of cell biology, biochemistry and neurobiology at Duke University Medical Center, said in a news release from the school.

He said this gradual development of diabetes “happens through what is called the parasympathetic nervous system, not directly through eating food. We think this parasympathetic response is potentially very important in type 2 diabetes.”

When people eat or smell food, their bodies begins to secrete insulin. A molecule called ankyrin B plays an important role in insulin response.

Experiments with mice lacking the molecule showed that ankyrin B deficiency impairs the parasympathetic chain of events that lead to insulin secretion. This has a measurable effect on blood sugar levels.

Further investigation revealed that one type of mutation in ankyrin B was associated with type 2 diabetes in Hispanics and whites.

The study was published online in the journal Science Signaling.

Getting a bit more calcium in your diet could help you live longer, new research suggests.

Swedish researchers found that men who consumed the most calcium in food were 25 percent less likely to die over the next decade than their peers who took in the least calcium from food. None of the men took calcium supplements.

The findings are in line with previous research linking higher calcium intake with lower mortality in both men and women, the researchers point out in a report in the American Journal of Epidemiology.

While many researchers have looked at calcium and magnesium intake and the risk of chronic disease, less is known about the association between consumption of these nutrients in food and mortality.

To investigate, Dr. Joanna Kaluza of the Karolinska Institutet in Stockholm and her colleagues looked at more than 23,000 Swedish men who were 45 to 79 years old at the study’s outset and were followed for 10 years. All had reported on their diet at the beginning of the study. During follow-up, about 2,358 died.

The top calcium consumers had a 25 percent lower risk of dying from any cause and a 23 percent lower risk of dying from heart disease during follow-up relative to men that had the least amount of calcium in their diet. Calcium intake didn’t significantly influence the risk of dying from cancer.

Men in the top third based on their calcium intake were getting nearly 2,000 milligrams a day, on average, compared to about 1,000 milligrams for men in the bottom third. The US Recommended Dietary Allowance (RDA) for calcium intake is 1,000 milligrams for men 19 to 50 years old and 1,200 milligrams for men 50 and over.

“Intake of calcium above that recommended daily may reduce all-cause mortality,” Kaluza and her colleagues conclude.

Calcium could influence mortality risk in many ways, they note, for example by reducing blood pressure, cholesterol, or blood sugar levels. For the men in the study, the main sources of calcium in the diet were milk and milk products and cereal products.

In contrast to calcium, there was no relationship between magnesium consumption and overall mortality or deaths from cancer or heart disease. Study participants’ intakes ranged from around 400 milligrams per day to around 525 milligrams; the RDA for magnesium is 420 milligrams for men 31 and older.

This analysis, the researchers say, may have found no effect for magnesium because all of the men in the study seemed to be getting enough of the mineral in their diet. “Further studies are needed in other populations with lower dietary magnesium intakes to address this issue,” they say.

Future research should also look into calcium and magnesium intake from drinking water, they add, which can be a significant source of these minerals.

SOURCE: American Journal of Epidemiology

Needle-exchange programs designed to cut injection drug users’ risk of HIV, the virus that causes AIDS, and other infections do seem to reduce needle sharing, but there is only limited evidence that they lower disease transmission, a new research review concludes.

Reporting in the journal Addiction, researchers say that based on their study — an analysis of five previous reviews of needle-exchange programs — the evidence for the programs’ effectiveness is weaker than generally thought.

However, they also stress that their review did not find needle-exchange programs to be ineffective either.

“The findings of this review should not be used as a justification to close NSPs (needle and syringe programs) or hinder their introduction,” write the researchers, led by Norah Palmateer, of Health Protection Scotland, part of the UK National Health Service.

“Insufficient or weak evidence of an effect is not evidence of no effect,” Palmateer told Reuters Health in an email. “It is more a reflection of the studies and evidence available.”

It is not that studies on needle-exchange programs have been “poor,” Palmateer said, but they are limited by the nature of their design.

Studies looking at needle-exchange programs have been observational, rather than controlled clinical trials where researchers would, for example, randomly assign some communities to start a program, and then compare them over time with program-free communities.

Observational studies, Palmateer noted, are subject to limitations like “selection bias.” For example, if those injection drug users at greatest risk of HIV are most likely to use the programs, then a study may find that program attendees have a higher rate of infection than drug users not involved in needle-exchange.

Needle-exchange programs have always been controversial, with opponents arguing that they sustain people’s addictions and send the wrong message about drug use. The U.S. just recently repealed a ban on federal funding for needle-exchange programs, though some cities have long had their own programs.

Advocates of the programs, including many public-health and HIV experts, point to studies showing that needle and syringe exchange can cut HIV transmission — such as a 2004 review by the World Health Organization (WHO) that concluded there is “compelling evidence” that the programs reduce HIV infections.

However, individual studies have come to mixed conclusions, including those covered by the WHO review, according to the current study.

Palmateer and her colleagues found that of the 10 studies in the WHO review focusing on HIV transmission, five had positive findings; of those five, four had weaknesses in their design that limit the conclusions that can be drawn.

Palmateer’s team also looked at two other reviews that covered many of the same studies as the WHO review. One research team came to similar conclusions as the WHO, while the other was more guarded — saying that the evidence that needle-exchange programs reduce HIV transmission is “modest.”

Overall, Palmateer and her colleagues conclude, there appears to be “tentative” evidence that needle-exchange programs reduce HIV transmission among injection-drug users.

When it came to hepatitis C, a liver infection usually spread through infected blood, there was insufficient evidence to say whether the programs are effective or not, according to Palmateer’s team. Of the five reviews she and her colleagues analyzed, the three major ones did not examine hepatitis C “in any depth,” the researchers write.

There was also insufficient evidence of the effectiveness of alternatives to standard needle-exchange programs — including vending machines that sell syringes and needles, and outreach programs that go to drug users rather than having them come to a clinic.

On the other hand, there was “strong” evidence across the reviews that needle-exchange programs reduce the sharing or reuse of dirty needles, and no evidence of harmful effects, according to Palmateer’s team.

Exactly why the evidence for disease prevention is not as strong is not entirely clear. Studies may have failed to detect an impact, but limitations of the programs themselves may also be at work.

For example, many of the needle-exchange programs studied in these reviews had strict limits on the number of syringes and needles they could give clients, Palmateer and her colleagues note. So while they might have reduced users’ needle sharing and reuse, it might not have been adequate.

It is not known what “level of coverage” — that is, the amount of injecting equipment given to clients — is needed to lower HIV and hepatitis C rates, according to Palmateer’s team. And at any rate, the optimal level will vary from one locale to another.

“The main public health implications of the findings are that a higher level of coverage of interventions, including (needle and syringe programs), is likely required to reduce blood-borne virus transmission,” Palmateer said.

She noted that this may be especially true of hepatitis C, which is most commonly transmitted through drug-equipment sharing. In the U.S., injection drug use is believed to account for most new cases of hepatitis C and about one-fifth of new HIV cases.