Omega imbalance can make obesity 'inheritable': study

July 16, 2010 by Marlowe Hood

Overeating combined with the wrong mix of fats in one's diet can cause obesity to be carried over from one generation to the next, researchers in France reported Friday.

Omega-6 and omega-3, both polyunsaturated fatty acids, are each critical to good health.

But too much of the first and not enough of the second can lead to overweight offspring, the scientists showed in experiments with mice designed to mirror recent shifts in human diet.

Over the last four decades, the ratio of omega-6 to omega-3 in a typical Western diet has shifted from a healthy five-to-one to 15-to-one in much of Europe, and up to 40-to-one in the United States.

In the of American women, the average ratio has gone from six-to-one to 18-to-one.

Earlier studies have established a link between such imbalances and .

But "this is the first time that we have shown a trans-generational increase in " linked to omega intake, said Gerard Ailhaud, a biochemist at the University of Nice-Sophia Antipolis and main architect of the study.

"Omega six is like a fat-producing bomb," he told AFP by phone.

Experts differ on whether obesity is more importantly due to the percentage of fat in one's diet or the sheer amount of calories consumed.

The findings, published in the US-based Journal of Lipid Research, add yet another dimension to the debate, and could shed new light on the that has swept across the globe, mainly in rich nations.

They also suggest that persistence within families of health-threatening -- while not genetic in origin -- may not be entirely due to either.

The link between omega imbalance and obesity "is probably epigenetic," said Ailhaud, referring to the complex process whereby the information in genes is translated into chemical activity.

"The and the DNA of the rodents has not been modified, but these factors can influence the way in which certain genes are expressed."

In the experiments, four generations of mice were fed a 35-percent fat diet with the omega imbalance now found in much of the developed world.

The result was progressively fatter mice at birth, generation after generation.

The rodents also developed insulin-resistance, a telltale symptom for diabetes 2, one of the most common -- and debilitating -- consequences of obesity in humans.

The equally undesirable increase in omega-6 and drop in omega-3 can be partly explained by the change from grass-fed to grain-fed livestock, Ailhaud explained.

Grass is rich in omega-3. "But to increase productivity, feed was shifted to grain meal, especially corn, which contains a high concentration of omega-6," he said.

Adding a small quantity of flaxseed oil to animal feed could help restore a healthy omega balance in meat and dairy products, he added.

There are three types of fatty acids -- saturated fats, monounsaturated fats and polyunsaturated fats.

In France, health authorities recommend that fat intake should between 30 and 40 percent of calories consumed, while the US Food and Drug Administration suggests a range of 20-to-30 percent.

Both governments agree that most of that intake should be from polyunsaturated and monosaturated fats such as fish, nuts and vegetable oils rather than the saturated fats found in red meat and dairy products.

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4 comments

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Miriam_Sawyer
not rated yet Jul 17, 2010
The article made no mention of what sort of diet would enable one to get the proper balance of these nutrients or what supplements to take.

I can't control what sort of feed the animals I eat are given.
LibertyJane
5 / 5 (2) Jul 17, 2010
Miriam,

You can certainly buy grass-fed beef!
Peep
not rated yet Jul 18, 2010
I believe the last para. is a simplistic, if not dangerously erroneous interpretation of the research on this matter.

A high consumption of (omega6) polyunsaturated fatty acid (found at various levels in most types of vegetable oil), may increase the likelihood of breast cancer in
postmenopausal women, and prostate cancer in men. Interestingly, there is no discernible association between saturated fatty acid intake and breast cancer risk.

http://www.ncbi.n...1890998/

Thus, a reduced intake of stearic acid (ie saturated fat) in proportion to vegetable-based oleic acid may increase the risk of endocrine cancers (breast cancer and prostate cancer) and other conditions in the elderly:

http://www.wjso.c...nt/1/1/5

Peep
5 / 5 (1) Jul 18, 2010
Moreover, the smoke-point of cooking oils is a measure of their oxidative degradeability, and in this respect, saturated fats are superior to most unrefined polyunsaturated and monounsaturated oils. The latter oils are heart-healthy when used as salad dressings and the like. The highly refined monounsaturated oils (such as extra light olive oil) which can be more safely used in cooking have the beneficial polyphenols removed.

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