Epidemic rates of overweight and worse, seen first in North America and now worldwide, have led to a hunt for quick, easy solutions.
So far, that search has proved fruitless. But studies have suggested that omega-3s produce effects that could be helpful, such as increased fat burning.
And some clinical trials indicate possible weight control benefits from fish oil and fish (See “Human research record encouraging but inconclusive”, below).
Recently, a team of U.S. researchers set out to see whether, when taken together with diet and exercise counseling, omega-3 fish oil supplements could yield greater weight loss over a six-month period.
The research was performed by scientists from The Cooper Institute… a non-profit organization dedicated to preventive medicine and founded by Air Force physician Ken Cooper, famed as the “Father of Aerobics” (Defina LF et al. 2011).
Trial finds no weight benefit from six-month fish oil routine
This was a placebo-controlled, randomized clinical trial involving 128 people with a body mass index between 26 and 40 (An adult whose BMI falls between 25 and 29.9 is considered overweight, and someone with a BMI of 30 or mroe is considered obese).
They were randomly assigned to receive either five omega-3 capsules per day, or five placebo capsules.
The participants in both groups received diet and exercise counseling, and 81 of the 128 completed the full six-month trial.
The researchers found that subjects in both groups lost more than five percent of their body weight during the 24 weeks, with no significant differences between the two groups.
As the Cooper team wrote, “Omega-3 fatty acids were not effective as an adjunct for weight loss in this otherwise healthy, overweight population” (Defina LF et al. 2011).
However, there was one odd aspect to the trial, in that the omega 3 supplements delivered 1,000 mg EPA and 200 mg DHA… a 5 to 1 ratio.
This unusual ratio might have affected the outcome, since it is about twice as high as the 2 to 1 EPA to DHA ratio commonly found in fish oil and whole fish.
Human research record encouraging but inconclusive
No prior research indicates that fish oil—or any other safe, healthful supplement—can produce substantial or rapid weight loss by itself. (Ephedrine-class chemicals can cut pounds, but have real health risks.)
But encouraging results from animal and human research alike indicate that diets rich in omega-3s push their consumers' metabolisms in directions likely to aid weight control over the long term (See the “Omega-3s & Metabolic Health” section of our news archive).
These are some of the studies we've reported in recent years. For more, see the “Omega-3s & Weight/Fitness” section of our website:
“Omega-3s Linked to Healthier Weight and Body Composition”—Australian clinical study in 124 people of varying weights, excluding people taking omega-3 fish oil supplements: 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. As the authors wrote, “Our findings suggest that [omega-3s] may play an important role in weight status and abdominal adiposity [excess belly fat.].” (Micallef M et al. 2009)
“Omega-3s Boost Weight Loss Benefits of Low-Cal Diets”—Czech pilot trial in 20 obese women: Women assigned to a very-low-calorie diet (VLCD) plus omega-3 supplements showed significantly greater weight losses, fat-burning, reductions in body mass index (BMI) and hip circumference, compared with those assigned to a very-low-calorie diet and placebo supplements (Kunesova M et al. 2006).
“Weight Loss Efforts Aided by Omega-3s”—European trial in 324 overweight people: High-dose omega-3 pills produced a greater sense of satisfaction (satiety) for up to two hours following a meal, compared with people who got low-dose omega-3 pills. (Parra D et al. 2008)
“Exercise + Omega-3s = Perfect Weight Loss Pair”—Australian trial in overweight to obese adults: Compared with people taking fish oil or sunflower oil without exercise, or a combination of sunflower oil and exercise, people put on a regimen of fish oil plus moderate aerobic exercise had lower total body fat, particularly in the abdominal region (Hill AM et al. 2007).
“Fish Oil Trims Diabetics' Belly and Blood Fat”—French clinical trial in 27 women with diabetes: Women assigned to fish oil showed significant reductions in their total fat mass, the size of the fat cells beneath the surface of their abdominal skin, and in a subset of inflammation-related genes in their belly fat (Kabir M et al. 2007).
Ample research also suggests that the standard American diet's overload of omega-6 fats from vegetable oils may promote obesity. This omega-6 overload also reduces the body's absorption of omega-3 fats.
We'll continue to follow research in this realm and report the results… positive or otherwise.
Andersson A, Nalsen C, Tengblad S, Vessby B. Fatty acid composition of skeletal muscle reflects dietary fat composition in humans. Am J Clin Nutr. 2002 Dec;76(6):1222-9.
Defina LF, Marcoux LG, Devers SM, Cleaver JP, Willis BL. Effects of omega-3 supplementation in combination with diet and exercise on weight loss and body composition. Am J Clin Nutr. 2011 Feb;93(2):455-62. Epub 2010 Dec 15.
Hill AM, Buckley JD, Murphy KJ, Howe PR. Combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors. Am J Clin Nutr. 2007 May;85(5):1267-74.
Kopecky J, Rossmeisl M, Flachs P, Kuda O, Brauner P, Jilkova Z, Stankova B, Tvrzicka E, Bryhn M. n-3 PUFA: bioavailability and modulation of adipose tissue function. Proc Nutr Soc. 2009 Nov;68(4):361-9. Epub 2009 Aug 24. Review.
Kunesova M, Braunerova R, Hlavaty P, Tvrzicka E, Stankova B, Skrha J, Hilgertova J, Hill M, Kopecky J, Wagenknecht M, Hainer V, Matoulek M, Parizkova J, Zak 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.
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.