Stored Calories May Raise Cancer Risk
Stored Calories May Raise Cancer Risk
Mouse Study: Cancer Risk Not From Calories Eaten, but From Calories Kept
Jan. 2, 2007 -- It's not the calories you eat -- it's the calories you don't burn off that increase cancer risk, studies of mice suggest.
It's now well known that a restricted-calorie diet cuts the risk of getting cancer and slows the growth of some cancers. Most researchers think this is directly related to calorie intake.
But not Tim Nagy, PhD, professor of nutrition sciences at the University of Alabama, Birmingham.
When you eat more calories than you burn off, you store the extra calories as fat. Nagy wondered whether it's these extra fat cells, rather than the extra calories themselves, that affect cancer risk.
To test this idea, Nagy's research team devised a clever experiment with mice genetically engineered to get prostate cancer.
They fed two groups of mice exactly the same number of calories.
But one group of mice lived in cages warmed to a balmy 80.6 degrees Fahrenheit. The other group's cages were kept at 71.6 degrees.
Mice in the cooler cages burned more calories to keep warm.
After three weeks, they weighed less than the warmer mice. And they were less likely to have prostate cancer.
In a second experiment, both groups of mice were allowed to eat all they liked.
The mice in the cooler cages ate about 30% more than the warmer mice.
They wound up as fat as the warm mice. And they got prostate cancer at about the same rate -- despite their extra calories.
Stored Calories May Raise Cancer Risk
Mouse Study: Cancer Risk Not From Calories Eaten, but From Calories Kept
Jan. 2, 2007 -- It's not the calories you eat -- it's the calories you don't burn off that increase cancer risk, studies of mice suggest.
It's now well known that a restricted-calorie diet cuts the risk of getting cancer and slows the growth of some cancers. Most researchers think this is directly related to calorie intake.
But not Tim Nagy, PhD, professor of nutrition sciences at the University of Alabama, Birmingham.
When you eat more calories than you burn off, you store the extra calories as fat. Nagy wondered whether it's these extra fat cells, rather than the extra calories themselves, that affect cancer risk.
To test this idea, Nagy's research team devised a clever experiment with mice genetically engineered to get prostate cancer.
Eat Same, Burn More Calories
They fed two groups of mice exactly the same number of calories.
But one group of mice lived in cages warmed to a balmy 80.6 degrees Fahrenheit. The other group's cages were kept at 71.6 degrees.
Mice in the cooler cages burned more calories to keep warm.
After three weeks, they weighed less than the warmer mice. And they were less likely to have prostate cancer.
Eat More, Burn More Calories
In a second experiment, both groups of mice were allowed to eat all they liked.
The mice in the cooler cages ate about 30% more than the warmer mice.
They wound up as fat as the warm mice. And they got prostate cancer at about the same rate -- despite their extra calories.