21 November 2006

Omega-3 an anti-obesity agent?

The omega-3 fatty acid, docosahexaenoic acid (DHA), suppressed the development of fat cells in vitro, and could lead to reductions in body fat, US researchers have reported.

The omega-3 fatty acid, docosahexaenoic acid (DHA), suppressed the development of fat cells in vitro, and could lead to reductions in body fat, US researchers have reported.

Fish oil, and other omega-3-rich sources, have previously been shown to decrease body fat in rodents.

How the study was done
The new research, published in the new issue of the Journal of Nutrition (Vol. 136, pp. 2965-2969), looked at the effects of DHA on cell growth, differentiation, cell death (apoptosis), and fat breakdown in cultured fat (3T3-L1) cells.

Hye-Kyeong Kim and co-workers from the University of Georgia state that the concentrations used in their study were based on physiological levels of free fatty acids (FFA).

“It was reported that plasma FFA levels were 0,5-2,3 millimoles per litre (mmol/L) in rats and 0,25-0,73 mmol/L in humans,” said Kim. “We selected 25-200 micromoles per litre as the experimental doses in our in vitro study.”

The Georgia-based researchers report that when added to a culture of preadipocytes (cells that can be stimulated to develop into fully-fledged fat cells, adipocytes) all the concentrations studied (25, 50, and 200 umol/L) resulted in a reduction in the number of viable cells. This was due, said the researchers, to an effect of DHA on adoptosis (programmed cell death).

Decrease in fat accumulation
They also report that DHA significantly decreased the accumulation of fat in the preadipocytes in a dose-dependent manner and the development (differentiation) of mature adipocytes in culture.

“These results demonstrate that DHA may exert its anti-obesity effect by inhibiting differentiation to adipocytes,” said the researchers.

“Therefore, it could mediate a reduction in body fat.”

Further studies are clearly needed to determine whether dietary and supplemental DHA could play a role in weight management in vivo.

Omega-3s have many benefits
The study adds to an ever-growing list of potential health benefits from the omega-3 polyunsaturated fatty acids, identified as one of the super-nutrients taking the food and supplements industry by storm. Much of its healthy reputation that is seeping into consumer consciousness is based on evidence that it can aid cognitive function, may help protect the heart against cardiovascular disease, and could reduce the risk of certain cancers.

Such reports have seen the number of omega-3 enriched or fortified products on the market increase.

However, fears about dwindling fish stocks and the presence of pollutants, such as methyl mercury, dioxins, and polychlorinated biphenols (PCBs), have pushed some academia and industry to start producing omega-3s from alternative sources, such as algae extraction or transgenic plant sources. Most extracted fish oils are molecularly distilled and steam deodorised to remove contaminants. - (Decision News Media, November 2006)

Read more:
How mom passes omega-3 to child
Omega fats stop mental decline


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