Overall, about two-thirds of adults in the U.S. are either overweight or obese and about 6 percent are extremely obese, putting them at an increased risk for diabetes, hypertension, heart disease, osteoarthritis, stroke, gallbladder disease, sleep apnea, respiratory problems and even certain cancers. Researchers have also discovered that obesity increases the risk for dementia, and a new study detailed in the online edition of the journal Human Brain Mapping may help to explain why.
When researchers at UCLA and the University of Pittsburgh scanned the brains of 94 people in the 70s, they found that the obese individuals had 8 percent less brain tissue than their normal-weight peers, and their brains looked 16 years older than the brains of lean people—evidence of “severe brain degeneration,” according to study author Paul Thompson, a UCLA professor of neurology. Those classified as overweight had 4 percent less brain tissue and their brains appeared to have aged prematurely by eight years.
For obese people, the areas of significant shrinkage was in the frontal and temporal lobes, areas of the brain critical for reasoning and judgment; the anterior cingulate gyrus, key to attention and decision-making; the hippocampus, which processes long-term memories; and basal ganglia, from which movement is initiated. Overweight people showed shrinkage in the basal ganglia and the parietal lobe, where we integrate sensory input, and in the corona radiata, which helps speed messages among regions of the brain that must work together for proper functioning.
While the participants of the study showed no outward signs of cognitive impairment at the time of the study, the researchers predicted that the premature aging and loss of brain volume will put the heavier subjects at greater risk of developing Alzheimer’s disease and other degenerative brain diseases. “That’s a big loss of tissue and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer’s and other diseases that attack the brain,” Thompson said.
Experts say people can greatly reduce their risk for Alzheimer’s and related diseases by exercising, eating healthily and keeping their weight under control. “A brain healthy diet is one that is heavy on fruits and nuts and low in fat and cholesterol,” says Lou-Ellen Barkan, president and CEO of the New York City chapter of the Alzheimer’s Association. “Obesity is definitely not a good thing for a healthy brain.”
But researchers say obesity isn’t just causing the brain to shrink—it is also trimming years off people’s lives. Economists at RTI International, a non-profit research organization in Research Triangle Park, N.C., analyzed data on 366,000 people and found that extremely obese people, those with a body mass index of 40 or greater, live three to 12 years less than their normal-weight peers. And extremely obese people who smoke live an average of 21 years less than non-smokers of normal weight. For instance, an 18-year-old white male who is of normal weight and does not smoke can expect to live to age 81, but if he’s extremely obese and a smoker, his life expectancy fall to 60. The researchers estimate that overall, Americans lost roughly 95 million years in 2008 by carrying around excess weight.
However, the study found that just being overweight or moderately obese has little or no effect on life span. Non-smokers who are overweight—meaning they have a body mass index of 29 or less—do not have shortened lives, and non-smokers who are obese — those with a BMI of 30 to 39—lose about a year or less off their lives. Lead author Eric Finkelstein says that may be because there are effective treatments to manage many of the health problems that often stem from extra pounds, such as hypertension, high cholesterol and diabetes. For example, 10 of the top 25 most prescribed medications target the three aforementioned diseases.
Findings of the RTI study are published online in the journal Obesity.
When researchers at UCLA and the University of Pittsburgh scanned the brains of 94 people in the 70s, they found that the obese individuals had 8 percent less brain tissue than their normal-weight peers, and their brains looked 16 years older than the brains of lean people—evidence of “severe brain degeneration,” according to study author Paul Thompson, a UCLA professor of neurology. Those classified as overweight had 4 percent less brain tissue and their brains appeared to have aged prematurely by eight years.
For obese people, the areas of significant shrinkage was in the frontal and temporal lobes, areas of the brain critical for reasoning and judgment; the anterior cingulate gyrus, key to attention and decision-making; the hippocampus, which processes long-term memories; and basal ganglia, from which movement is initiated. Overweight people showed shrinkage in the basal ganglia and the parietal lobe, where we integrate sensory input, and in the corona radiata, which helps speed messages among regions of the brain that must work together for proper functioning.
While the participants of the study showed no outward signs of cognitive impairment at the time of the study, the researchers predicted that the premature aging and loss of brain volume will put the heavier subjects at greater risk of developing Alzheimer’s disease and other degenerative brain diseases. “That’s a big loss of tissue and it depletes your cognitive reserves, putting you at much greater risk of Alzheimer’s and other diseases that attack the brain,” Thompson said.
Experts say people can greatly reduce their risk for Alzheimer’s and related diseases by exercising, eating healthily and keeping their weight under control. “A brain healthy diet is one that is heavy on fruits and nuts and low in fat and cholesterol,” says Lou-Ellen Barkan, president and CEO of the New York City chapter of the Alzheimer’s Association. “Obesity is definitely not a good thing for a healthy brain.”
But researchers say obesity isn’t just causing the brain to shrink—it is also trimming years off people’s lives. Economists at RTI International, a non-profit research organization in Research Triangle Park, N.C., analyzed data on 366,000 people and found that extremely obese people, those with a body mass index of 40 or greater, live three to 12 years less than their normal-weight peers. And extremely obese people who smoke live an average of 21 years less than non-smokers of normal weight. For instance, an 18-year-old white male who is of normal weight and does not smoke can expect to live to age 81, but if he’s extremely obese and a smoker, his life expectancy fall to 60. The researchers estimate that overall, Americans lost roughly 95 million years in 2008 by carrying around excess weight.
However, the study found that just being overweight or moderately obese has little or no effect on life span. Non-smokers who are overweight—meaning they have a body mass index of 29 or less—do not have shortened lives, and non-smokers who are obese — those with a BMI of 30 to 39—lose about a year or less off their lives. Lead author Eric Finkelstein says that may be because there are effective treatments to manage many of the health problems that often stem from extra pounds, such as hypertension, high cholesterol and diabetes. For example, 10 of the top 25 most prescribed medications target the three aforementioned diseases.
Findings of the RTI study are published online in the journal Obesity.
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