Healthy weight extends life?20th July 2007
People whose weight remains within a healthy range may extend their lives, because of the relationship between the brain, and the metabolic hormone insulin, a US study has found.
The study was led by Morris White, a researcher at the Howard Hughes Medical Institute, and measured the effects on mice of reducing insulin signals inside brain cells.
Writing in the journal Science, the team said mice with reduced insulin signals in the brain lived longer, and that the result might also be applicable to humans.
Previous research has also shown that reducing insulin activity needed to regulate levels of glucose in the bloodstream contributes to longer life.
The key to the benefits lies with a particular protein, IRS2, which carries the insulin signal in the brain. Mice who had half the amount of the protein lived 18% longer than normal mice.
The benefits of the protein outweighed the disadvantages of being overweight and having higher levels of insulin. The mice dosed with this protein were more active and their ability to metabolise glucose was similar to that of much younger mice.
The protein is believed to delay the onset of cancer and cardiovascular disease, thereby extending life expectancy.
The research opened up the possibility of a new form of drug specifically aimed at reducing IRS2 activity in the brain, the researchers said.
White said the findings backed up common sense; that a good diet and exercise will keep you healthy.
He said diet, exercise and lower weight keep peripheral tissues sensitive to insulin, reducing the amount and duration of insulin secretion needed to keep blood glucose under control when food is consumed. The brain is consequently exposed to less insulin.
Next, the team plans to investigate possible links between IRS2 signalling and dementia, which research has shown is associated with obesity and high insulin levels.
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Wednesday 25th July 2007 @ 21:50
I just thought I would post this, since the Science site wouldn't let me in to the article.
The report above says:
"Mice who had half the amount of the protein lived 18% longer than normal mice."
"The benefits of the protein outweighed the disadvantages of being overweight and having higher levels of insulin. The mice dosed with this protein were more active and their ability to metabolise glucose was similar to that of much younger mice."
I feel confused by the seeming conflict between saying the mice benefited from having half the amount of the protein and from being dosed with it. Maybe the "benefit" of being dosed is not the same benefit of life extension mentioned in the headline?
Oh, well, there are greater frustrations. I just thought that I would post my confusion.
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