Low-calorie diet slows aging in monkeys: Study

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Low-calorie diet slows aging in monkeys: Study
www.chinaview.cn 2009-07-10 15:43:21

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BEIJING, July 10 (Xinhuanet)-- Low-calorie diet increases lifespan of monkeys, according to a new U.S. study. It suggests that caloric restriction could also delay aging in humans.
In the 20-year-old study, rhesus monkeys were put on a strict reduced-calorie diet. The monkeys were three times less likely to die from age-related diseases like heart disease, cancer and diabetes than monkeys that ate as they liked, according to the scientists.
"We have been able to show that caloric restriction can slow the aging process in a primate species," Richard Weindruch of the University of Wisconsin in Madison, who led the study, said in a statement.
"We observed that caloric restriction reduced the risk of developing an age-related disease by a factor of three and increased survival," Weindruch said.
He said the results should have "relevance in humans" as monkeys are "closely related to humans".
The key to the diet was to make sure that it made it nutritious. The reason why historically people had died younger even though they ate less was because the diet was not nutritious.
"It is important that we are studying calorie restriction and not malnutrition, so there is a fine line between a low enough level of calories but still enough to provide adequate nutrition," he said.
"Just because humans may have been eating less previously, it does not necessarily follow that they were eating a complete, nutritious diet."
The study was published Thursday in by Science magazine.
(Agencies)
Editor: Huma Sheikh

Mengapa penting untuk menurunkan berat badan?

Tahukah anda, kelebihan berat badan dapat menimbulkan penyakit al.:

• jantung dan pembuluh darah


• diabetes


• osteoarthritis dan gout


• keganasan/kanker


• penyakit yang menyerang kandung empedu


• penyakit perlemakan hati


• sleep apnoea


• depresi

Brown fat may help adults lose weight: Study

Brown fat may help adults lose weight: Study
www.chinaview.cn 2009-04-10 17:13:27

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BEIJING, April 10 (Xinhuanet) -- A new U.S. study shows healthy adults still have significant deposits of brown fat -- previously believed to be present in babies and children -- that could lead to a new way to lose weight.
Researchers said Wednesday brown fat burns calories faster than regular fat that stores energy and comprises most body fat. It is normally so dormant in adults that there has been debate over how much adults have or whether they have it at all.
In three studies published in Thursday's New England Journal of Medicine, researchers report finding brown fat in most adults and discovering they can detect it by exposing people to cold. In some cases, adults who had more active areas of brown fat were thinner.
The hope is that if a way can be found to activate this brown fat and get the body to make more of it, people could burn off extra calories without additional exercise.
The researchers analyzed a database of 1,972 patients who had undergone positron emission tomography/computed tomography scans for a variety of reasons during a three-year period.
Senior author Dr. C. Ronald Kahn said the study shows brown fat not only exists in adults, but it is metabolically active.
"The fact that there is active brown fat in adult humans means this is now a new and important target for the treatment of obesity and type 2 diabetes," Kahn said in a statement.
(Agencies)
Editor: Huma Sheikh

Adults with brown fat don't burn calories as believed

Adults with brown fat don't burn calories as believed
www.chinaview.cn 2009-04-09 11:10:05

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BEIJING, April 9 (Xinhuanet) -- It was generally believed, but could be worng, that humans lose brown fat after infancy, no longer needing it once the shivering response kicks in, said Thursday's issue of the New England Journal of Medicine.
Papers made by three groups of researchers indicate that nearly every adult has little blobs of brown fat that can burn huge numbers of calories when activated by the cold, as when sitting in a chilly room that is between 16 and 19 degrees centigrade.
Thinner people appear to have more brown fat than heavier people; younger people more than older people; people with lower glucose levels, presumably reflecting higher metabolic rates, have more than those whose metabolisms are more sluggish; and women have more than men. People taking beta blockers for high blood pressure or other medical indications have less active brown fat.
"The thing about brown fat is that it takes a very small amount to burn a lot of energy," said Dr. C. Ronald Kahn, head of the section on obesity and hormone action at the Joslin Diabetes Center in Boston.
The fat really is brown, researchers said, because it is filled with mitochondria, the tiny energy factories of cells. Mitochondria contain iron, giving the tissue a reddish brown color.
The hope is that scientists may find safe ways to turn on people's brown fat, allowing them to lose weight by burning more calories. But researchers caution that while mice lose weight if they activate brown fat, it is not clear that people would shed pounds -- they might unwittingly eat more, for example.
The data on global patterns of obesity are not good enough to say whether living in a cold climate makes people thinner.
(Agencies)
Editor: Wang Hongjiang

Less sugar, more fiber reduce diabetes risk in Latino teens

Less sugar, more fiber reduce diabetes risk in Latino teens
www.chinaview.cn 2009-04-08 19:25:50

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BEIJING, April. 8 (Xinhuanet) -- A new study says reduced amount of sugar and more fiber can cut risk factors linked with type 2 diabetes in overweight Latino adolescents.
Researchers said reducing sugar intake by the equivalent of one can of soda per day and increasing fiber intake by the amount equivalent to one half cup of beans per day can reduce diabetes risk factors in Latino teens.
Dr. Michael Goran, of the University of Southern California, Los Angeles, and colleagues analyzed data from a 16-week clinical trial in which 66 overweight Latino teens were assigned to one of three groups: (1) a nutrition-only group, with weekly classes directed at reducing sugar and increasing fiber intake, (2) nutrition education plus twice-weekly strength training, and (3) a comparison group with no intervention other than occasional non-health related incentives (such as t-shirts) and phone calls to enhance retention.
The percentage of teens that reduced sugar intake and increased fiber intake was similar in all three groups, hovering around 55 and 59 percent, respectively.
Participants who reduced their sugar intake had significant drops in blood glucose levels and in insulin levels. Both of these changes would be expected to decrease their risk of diabetes.
Also, those who increased their fiber intake had a significant drop in body weight-for-height and in body fat levels.
"Latino children are more insulin resistant and thus more likely to develop obesity-related chronic diseases than their white counterparts," the researchers said.
"To date, only a few studies have examined the effects of a high-fiber, low-sugar diet on metabolic health in overweight youth, and to our knowledge, none have tested the effects of this type of intervention in a mixed-sex group of Latino youth," said the researchers.
(Agencies)
Editor: Huma Sheikh

Study links larger waist size with heart failure

Study links larger waist size with heart failure
www.chinaview.cn 2009-04-08 09:05:42

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WASHINGTON, April 7 (Xinhua) -- A U.S. study has found that larger waist circumference is associated with increased risk of heart failure in middle-aged and older populations, adding to the growing evidence that a person's waist size is an important indicator of heart health.
Researchers from Beth Israel Deaconess Medical Center (BIDMC), a teaching hospital of Harvard Medical School, reported their findings online on Tuesday in the Rapid Access Report of the journal Circulation: Heart Failure.
They said that waist size was a predictor of heart failure even when measurements of body mass index (BMI) fell within the normal range.
"Currently, 66 percent of adults in the United States are overweight or obese," explains Emily Levitan, first author of the study. "Knowing that the prevalence of heart failure increased between 1989 and 1999, we wanted to better understand if and how this increase in obesity was contributing to these rising figures."
A life-threatening condition that develops when the heart can no longer pump enough blood to meet the body's needs, heart failure (also known as congestive heart failure) is usually caused by existing cardiac conditions, including high blood pressure and coronary artery disease.
Heart failure, which is the leading cause of hospitalization among patients at the age of 65 and older, is characterized by symptoms like fatigue and weakness, difficulty walking, rapid or irregular heartbeat, and persistent cough or wheezing.
The researchers examined two Swedish population-based studies, the Swedish Mammography Cohort (36,873 women aged between 48 to 83) and the Cohort of Swedish Men (43,487 men aged between 45 to 79) who answered questionnaires for information about height, weight and waist circumference.
Over a seven-year period between January 1998 and December 2004,a total of 382 first-time heart-failure events were reported among the women group (including 357 hospital admissions and 25 deaths) and 718 among men (accounting for 679 hospital admissions and 39 deaths.)
The researchers found that based on the answers provided, 34 percent of the women were overweight and 11 percent were obese, while 46 percent of the men were overweight and 10 percent were obese.
"By any measure -- BMI, waist circumference, waist to hip ratio or waist to height ratio -- our findings showed that excess body weight was associated with higher rates of heart failure," explains Levitan.
Further breakdown of the numbers showed that among the women with a BMI of 25 (within the normal range), a 10-centimeter higher waist measurement was associated with a 15 percent higher heart failure rate; women with a BMI of 30 had an 18 percent increased heart failure rate.
In men with a BMI of 25, a 10-centimeter higher waist circumference was associated with a 16 percent higher heart failure rate; the rate increased to 18 percent when men's BMI increased to 30.
Furthermore, adds Levitan, among the men, each one-unit increase in BMI was associated with a four percent higher heart failure rate, no matter what the man's waist size were. In women, she adds, BMI was only associated with increased heart failure rates among the subjects with the largest waists.
Finally, the authors found that the association between BMI and heart-failure events declined with age, suggesting that the younger the person, the greater the impact of weight to heart health.
"This study reinforces the importance of maintaining a healthy weight," says Levitan. "Previous research has looked at various types of heart disease and related health issues, and no matter the particulars of the study, they've all been pretty consistent in determining that excess body weight increases a person's risk of heart disease."
Editor: An

Weight gain early in life leads to physical disabilities in older adults: study

Weight gain early in life leads to physical disabilities in older adults: study
www.chinaview.cn 2009-04-08 03:10:07

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WASHINGTON, April 7 (Xinhua) -- Carrying extra weight earlier in life increases the risk of developing problems with mobility in old age, even if the weight is eventually lost, according to a new research by the Sticht Center on Aging at Wake Forest University School of Medicine.
The study, funded by the National Institute on Aging and the Wake Forest University Claude D. Pepper Older Americans Independence Center, will appear in the April 15 issue of the American Journal of Epidemiology.
"In both men and women, being overweight or obese put them at greater risk of developing mobility limitations in old age, and the longer they had been overweight or obese, the greater the risk," said lead investigator Denise Houston, an assistant professor of gerontology at the School of Medicine and an expert on aging and nutrition. "We also found that, if you were of normal weight in old age but had previously been overweight or obese, you were at greater risk for mobility limitations."
Houston added that dropping weight later in life can lead to problems with mobility because weight loss later in life is usually involuntary and the result of an underlying chronic condition.
The study is based on data collected in the Health, Aging and Body Composition study, which enrolled Medicare recipients in Pittsburgh, Pennsylvania, and Memphis, Tennessee, between April 1997 and June 1998. Participants had to be well-functioning, living in the community, and free of life-threatening illness.
The researchers defined mobility limitation as difficulty walking a quarter-mile or climbing 10 steps. They analyzed information from 2,845 participants who were on average 74 years old. Participants reported no problems with mobility at the beginning of the study. Information on new mobility limitations was collected every six months over seven years of follow-up.
Using participants' body mass index (BMI), a measurement equal to a person's weight in kilograms divided by height in meters squared, at different age intervals, the researchers found that women who were overweight or obese (BMI of 25 or greater) from their mid-20s to their 70s were nearly three times more likely to develop mobility limitations than women who were normal weight throughout.
The risk for men was slightly less -- they were about 1.6 times more likely to develop mobility limitations, according to the study.
The study also found that women who were obese (BMI of 30 or greater) at age 50, but not in their 70s, were 2.7 times more likely to develop mobility limitations compared to women who were not obese throughout. Men who were obese at 50, but not in their 70s, were 1.8 times more likely to develop mobility limitations than men who never carried the extra weight.
Carrying extra weight can strain joints, hinder exercise and lead to chronic conditions, such as diabetes, arthritis and heart disease, that are directly related to the development of mobility limitations, Houston said.
The results are significant, Houston added, because the elderly population in the United States is growing, and is expected to double by the year 2030 to about 20 percent.
"Over the past couple of decades there has been a trend towards declining rates of physical disability in older adults," Houston said. "However, the dramatic increase in overweight and obesity in the United States may reverse these declines and may lead to an increase in physical disability among future generations of older adults. The data suggest that interventions to prevent overweight and obesity in young and middle-aged adults may be useful in preventing or delaying the onset of mobility limitations later in life."
Editor: Yan

Big belly, obesity linked to increased risk of restless legs syndrome

Big belly, obesity linked to increased risk of restless legs syndrome
www.chinaview.cn 2009-04-07 11:15:54

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　WASHINGTON, April 6 (Xinhua) -- A new study showed both obesity and a large belly appear to increase the risk of developing restless legs syndrome (RLS), a common sleep disorder characterized by an irresistible urge to move legs.
The research will be published Tuesday in a print issue of Neurology, the medical journal of the American Academy of Neurology.
It is estimated that 5-10 percent of adults in the United States have RLS and the disorder often has a substantial impact on sleep, daily activities and quality of life.
For the study, researchers questioned 65,554 women and 23,119 men, all of whom were health professionals who took part in the U.S. Health Professionals Follow-Up Study or the Nurses' Health Study II. None of the participants had diabetes, arthritis or were pregnant. Of the groups, 6.4 percent of the women and 4.1 percent of the men were identified as having RLS.
The research found men and women with a body mass index (BMI) score over 30 were nearly one-and-a-half times more likely to have RLS than people who were not obese.
In addition, people who were in the top 20 percent of the group for highest waist circumference were more than one-and-a-half times more likely to have RLS than the bottom 20 percent of the group with the lowest belly size. The results were the same regardless of age, smoking, use of antidepressants or anxiety.
"These results may be important since obesity is a modifiable risk factor that is becoming increasingly common in the United States," said study author Xiang Gao, with the Harvard School of Public Health in Boston. "More research is needed to confirm whether obesity causes RLS and whether keeping a low BMI score and small waist size could help prevent RLS."
Gao said some studies suggest that obese people have lower dopamine receptor levels in the brain. "Since decreased dopamine function is believed to play a critical role in RLS as well, this could be the link between the two." Dopamine is a chemical naturally produced by the body that transmits signals between nerve cells.
Editor: An

Obesity can shorten lifespan for 10 years

Obesity can shorten lifespan for 10 years
www.chinaview.cn 2009-03-18 08:53:27

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BEIJING, March 18 (Xinhuanet) -- Those who are extremely obese may live 10 years shorter than they should have lived, according to researchers in UK as quoted by media reports Wednesday.
An overweight pedestrian sits on a wall outside the Houses of Parliament in London in this file photo. (Xinhua/Reuters File Photo)Photo Gallery>>>
The researchers examined the findings of 57 studies involving about 900,000 adults from the United States and Europe and followed them for 10 to 15 years. About 70,000 of the participants died in the course of the study.
They used the BMI (body mass index) measures and found that those who are about 40 or more pounds (some 18 kg) over a healthy weight may cut about three years off their lives, mostly from heart disease and stroke. Those who are extremely obese, about 100 or more pounds over a healthy weight, could be shortening their lives by as many as 10 years.
Being extremely obese is similar to the effect of lifelong smoking, said Richard Peto, one of the lead researchers and a professor of medical statistics at Oxford University in England.
Above a healthy weight, every 5-point increase in BMI increases the risk of early death by about 30 percent. People with a BMI between 25 and 29.9, which means they are overweight but not obese, could be shortening their life span by a year.
It "provides a much clearer picture of the risk associated with various levels of being overweight or obese," said Michael Thun, emeritus vice president of epidemiological research at the American Cancer Society.
"Once you gain weight, it's hard to lose it and easy to gain more," said Thun, therefore, to stop weight gain became much more important.
(Agencies)
Editor: Mo Hong'e

Study sheds new light on link between obesity, infertility

Study sheds new light on link between obesity, infertility
www.chinaview.cn 2009-03-04 06:32:42

WASHINGTON, Mar. 3 (Xinhua) -- Obese women have alterations in their ovaries which might be responsible for an egg's inability to make an embryo, according to a new study accepted for publication in the U.S. Endocrine Society's Journal of Clinical Endocrinology &Metabolism.
Obese women trying to become pregnant experience longer times to conception, even if they are young and have a regular menstrualcycle. This study sought to determine if there are alterations in an egg's environment in obese women which contribute to poorer reproductive outcomes.
"Characteristics of eggs are influenced by the environment in which they develop within the ovary," said Rebecca Robker, of Adelaide University in Australia and lead author of the study. "Our study found that obese women have abnormally high levels of fats and inflammation in the fluid surrounding their eggs which can impact an egg's developmental potential."
According to Robker, the fats might alter the very sensitive metabolism of the egg and such changes are known to be harmful to embryo formation. In addition, inflammation can damage cells and when this happens to eggs it can affect embryo survival.
For this study, researchers followed 96 women seeking assisted reproduction at a private clinic in South Australia from February 2006 to April 2007. Robker and her colleagues measured hormone and metabolite levels in follicular fluid obtained from the subjects' ovaries during their egg collection procedures. They found that obese women exhibited an altered ovarian follicular environment, particularly increased metabolite and androgen activity levels, which may be associated with poorer reproductive outcomes.
"Obesity is well known to cause changes in blood lipids and heightened inflammation which detrimentally affects a person's general health," said Robker. "Our research shows that obesity similarly changes the environment in the ovary which bathes and nourishes a woman's developing eggs."
Editor: Mu Xuequan