Study finds higher omega-3 levels in people with lower weights and body mass indices; Overweight subjects had lower omega-3 blood levels 08/03/2009
The truth is that exercise, portion control, and nutrition remain the proven approaches.
We've reported on animal and human studies that link diets higher in omega-3s to a fat-burning boost, and to better body compositions and weight control.
(Links to those articles can be found at the bottom of this one.)
Now, researchers from Australia's University of Newcastle have linked higher blood levels of the omega-3 fatty acids EPA and DHA to lower rates of obesity.
Compared to people with a healthy weight, the cell membranes of overweight and obese people in the study were nearly 14 percent lower in omega-3s… a dramatic difference.
Their conclusion was clear:
The researchers recruited 124 people of varying weights, excluding people taking omega-3 fish oil supplements:
- 21 people with healthy weight-height ratios (body mass index, or BMI);
- 40 people classified as overweight;
- 63 people classified as obese.
Lead author Monohar Garg, Ph.D., and his colleagues found an inverse relationship between participants' omega-3 (DHA plus EPA) blood levels, and their BMIs, waist size, and hip circumference.
That is, people with higher omega-3 blood levels had lower BMIs, narrower waists, and smaller hip circumferences.
Omega-3s accounted for 5.25 percent of all fatty acids in the red blood cell membranes of the healthy-weight participants.
In contrast, omega-3s constituted only 4.53 percent of fatty acids in the red blood cell membranes of obese participants: nearly 14 percent less than in the healthy-weight participants.
As the Aussie team wrote, "…[Other] studies, along with our observations, suggest that omega-3 supplementation may play an important role in preventing weight gain and improving weight loss when omega-3s are supplemented concomitantly with a structured weight-loss program.”
(In fact, there's already been at least one pilot clinical trial in which omega-3s were added to a structured weight-loss program, and it produced encouraging results: see "Omega-3s Boost Weight Loss Benefits of Low-Cal Diets”.)
Aussie findings fit with "pharmacology” of omega-3s
The Australian team stressed that the available evidence supports the value of omega-3s for weight management:
Animal studies suggest that omega-3s may increase burning of body fat by the process known as thermogenesis, in which oxidation of body fat burns it off in the form of body heat (Mori TA 2004).
And one human study found that omega-3s boosted the feeling of fullness after a meal, among overweight and obese people participating in a weight loss program (Parra Det al. 2008).
Appetite control is linked in part to omega-3s' effects on levels of hormones like ghrelin and leptin, but a full understanding remains out of reach.
As with all such uncontrolled studies, the results do not prove that the link between higher omega-3 levels and less excess body fat is causal …especially since the researchers appear not to have taken into account other diet-lifestyle factors that people within the high- and low-omega-3 groups may have had in common.
Accordingly, the authors called for more controlled, clinical trials, saying that the positive results of most studies conducted to date "…make the basis for conducting more intervention trials in adults examining the influence of dietary supplementation with omega-3-rich fats/oils in assisting weight loss and weight maintenance” (Micallef M et al. 2009).
We wish that more research dollars flowed to research into lifestyle factors affecting weight—including dietary patterns and individual nutrients—with fewer going toward the elusive and so far fruitless search for an enormously profitable "magic bullet” weight control drug.
For more on this topic see these previous articles:
- "Diet Face-Off Favors Low-Carb and Mediterranean Plans”
- "Food Allies in the Weight War: Spices, Tea, and Fish”
- "Wild Salmon Excels for Sports and Fitness”
- "Omega-3s Boost Weight Loss Benefits of Low-Cal Diets”
- "Weight Loss Efforts Aided by Omega-3s”
- "Omega-3s Advised for Burning Fat and Curbing Appetite”
- "Exercise + Omega-3s = Perfect Weight Loss Pair”
- Klein-Platat C, Drai J, Oujaa M, Schlienger JL, Simon C. Plasma fatty acid composition is associated with the metabolic syndrome and low-grade inflammation in overweight adolescents. Am J Clin Nutr. 2005 Dec;82(6):1178-84.
- Kunesová M, Braunerová R, Hlavatý P, Tvrzická E, Stanková B, Skrha J, Hilgertová J, Hill M, Kopecký J, Wagenknecht M, Hainer V, Matoulek M, Parízková J, Zák A, Svacina S. The influence of n-3 polyunsaturated fatty acids and very low calorie diet during a short-term weight reducing regimen on weight loss and serum fatty acid composition in severely obese women. Physiol Res. 2006;55(1):63-72. Epub 2005 Apr 26.
- Micallef M, Munro I, Phang M, Garg M. Plasma n-3 polyunsaturated fatty acids are negatively associated with obesity.Br J Nutr. 2009 May 19:1-5. [Epub ahead of print]
- Mori TA, Burke V, Puddey IB, Shaw JE, Beilin LJ. Effect of fish diets and weight loss on serum leptin concentration in overweight, treated-hypertensive subjects. J Hypertens. 2004 Oct;22(10):1983-90.
- Mori TA. Effect of fish and fish oil-derived omega-3 fatty acids on lipid oxidation. Redox Rep. 2004;9(4):193-7. Review.
- Parra D, Ramel A, Bandarra N, Kiely M, Martínez JA, Thorsdottir I. A diet rich in long chain omega-3 fatty acids modulates satiety in overweight and obese volunteers during weight loss. Appetite. 2008 Nov;51(3):676-80. Epub 2008 Jun 14.
- Ramel A, Martinéz A, Kiely M, Morais G, Bandarra NM, Thorsdottir I. Beneficial effects of long-chain n-3 fatty acids included in an energy-restricted diet on insulin resistance in overweight and obese European young adults. Diabetologia. 2008 Jul;51(7):1261-8. Epub 2008 May 20.
- Yanagita T, Nagao K. Functional lipids and the prevention of the metabolic syndrome. Asia Pac J Clin Nutr. 2008;17 Suppl 1:189-91. Review.