Scientists have produced the first direct evidence that fat accelerates aging, possibly speeding theunraveling of crucial genetic structures inside cells that wither with age.A team of researchers from the United States and Britain found that the more people weigh.
The older their cells appear on amolecular level, with obesity adding the equivalent of nearly nine years of age to a person’s body. The findings suggest that many health problems associated with being overweight — heart disease, cancer, diabetes, arthritis — mayresult from fat cells hastening the natural aging process."We’ve known obesity increases your risk of many diseases, and of dying early. What’s novel here is that it seems that fat itselfactually accelerates the aging process," said Tim Spector of St.
Thomas Hospital in London, who led the study, which was publishedonline yesterday by the Lancet medical journal. "This may not be apparent because these people may not have as many wrinkles. Butunderneath it looks like they are aging at a faster rate."That could help explain, for example, why an alarming number of obese children are developing the most common form of diabetes,which had been known as "adult-onset" diabetes; prior to the surge of obesity among the young, it almost invariably had been seenonly in adults."It might just change the whole of the body’s metabolism in a way that increases aging and increases the risk for all the agingdiseases," Spector said.Other researchers said the findings are provocative and could lead to fundamental new insights into the effects of fat on amolecular level at a time when public health experts are alarmed about the number of obese people."We know obese people live, on average, less time. Here we are going into the DNA sequence of these people and showing thiscondition is associated with a biomarker of aging," said Eric Ravussin of the Pennington Biomedical Research Center in Baton Rouge,La.
"I think it’s going to stimulate a lot of research."The study comes amid intense debate over the impact of obesity. More than two-thirds of Americans are overweight, including aboutone-third who are obese, raising concern the nation could be facing an epidemic of weight-related illnesses. Skeptics continue to challenge that assertion and question the new findings, saying the researchers had failed to rule out thepossibility that other factors may be responsible for the results. People who are overweight, for example, may not get enoughexercise, which could account for premature aging."It is impossible to determine if the ‘aging’ association with obesity is due to obesity itself or some other factors that co-varywith obesity, such as diet, physical activity, fitness, or other lifestyle factor," Glenn A. Gaesser, of the University of Virginiain Charlottesville, wrote in an e-mail.But Spector said the results are consistent with recent findings that, contrary to the long-held belief that fat cells are inertblobs, they churn out a host of substances that can be toxic to the body."So it may be the body has to repair itself much faster and that accelerates the aging process," Spector said in a telephoneinterview. "We don’t fully understand all the mechanisms of how obesity causes ill health, but this may be a central one thatunderpins all of them."In addition, the researchers found that the higher levels of a hormone in the blood produced by fat cells called leptin, the shorterthe telomeres.The researchers found a similar relationship with smoking, with the length of telomeres shortening with the number of cigarettes thesmokers in the group smoked.Rudolph L. Leibel of Columbia University said the findings were provocative but did not necessarily mean people who are overweight,or have short telomeres, are destined to die young."It may be that in a biological sense the aging process is accelerated in these individuals, but that in and of itself doesn’tnecessarily permit you to predict what the outcome will be," he said. "Maybe the telomere shortening is comparable to gray hair.Somebody who has gray hair is more likely to be older, but it doesn’t cause aging."
