Fish Oil for Weight Loss. Does It Help?
Many medical doctors are ‘prescribing’ fish oil supplements more and more to their patients for a variety of reasons. The current school of thought is that supplementing your diet with long-chain n-3 fatty acids (FAs) from fish or fish oil may independently improve cardiovascular, metabolic and even immune system health. According to the American Heart Association, omega-3 fatty acids tend to decrease risk of abnormal heartbeats, decrease triglyceride (blood fat) levels, slow the growth rate of plaque on artery walls and slightly lower blood pressure.
However, the results of many research studies are conflicting on whether or not fish oil is beneficial for weight loss and fat oxidation. It is somewhat controversial. Based upon inconclusive research, the best course of action may be to combine lifestyle modification with supplementation versus doing either as a stand-alone treatment.
What does the research indicate regarding fish oil supplementation and weight loss?
There is not a lack of research in this area, and there is a lack of consistent and reliable results. One study showing positive results, conducted at the University of South Australia, was published in the American Journal of Clinical Nutrition in 2007. Researchers examined the effects of n-3 fatty acid supplementation and regular exercise on body composition and cardiovascular health. Overweight volunteers (a BMI of greater than 25 kg/m²) with high blood pressure, high cholesterol/high blood triglyceride levels were randomly assigned to one of three groups: fish oil (FO) and exercise (FOX), sunflower oil and no exercise (SO: control) or sunflower oil and exercise (SOX). The fish oil group consumed 6 g of tuna daily (provides about 1,900 mg of n-3 fatty acids). The exercise program consisted of 45 minutes of walking, three days per week at 75% of their maximum heart rate. Blood tests at the beginning of the study and after 6 and 12 weeks were taken to measure cholesterol/triglycerides, blood pressure and arterial function. Body composition was measured (by dual-energy X-ray absorptiometry) at the start and completion of the study. FO supplementation lowered triglyceride levels and increased HDL (good) cholesterol as well as significantly improved arterial vasodilation. Interestingly, both FO supplementation and exercise independently but significantly reduced body fat more so than the other interventions/control.
Another study, conducted by the Department of Nutrition at the University of Copenhagen, was published in the Journal of Nutrition & Metabolism (2011). The objective was to see if supplementation of n-3 long-chain fatty acids increased fat burning (oxidation) and prevented obesity in 78 overweight boys, aged 13-15 years, with a high total body fat percentage (30 ± 9%). Participants were randomly assigned to eat either bread with fish oil (1,500 mg per day) or bread with vegetable oil (the same amount) for 16 weeks. They were counseled to improve their diet and exercise habits. Counseling appeared to reduce sugar intake but did not alter physical activity levels. While both groups lost body fat, fish oil supplementation did not significantly affect resting metabolic rate (RMR), fat oxidation or body composition. In the first study, however, participants did exercise.
What about eating fish?
You can consume seafood/fish as many varieties are an excellent source of two potent types of omega-3 fatty acids: docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Varieties of seafood that are highest in omega-3 fatty acids per 200-calorie serving include salmon, mackerel, anchovies, oysters, herring, tuna and sardines. Each provides close to 2,000 mg of omega-3 fatty acids per 200-calorie serving.
Should I take a fish oil supplement? What should I look for in a fish oil supplement?
For most individuals, taking a fish oil supplement (and/or consuming fatty fish) is not risky and may offer health benefits, particularly when combined with a regular, moderately-intense exercise routine. However, you should always check with your physician or other health care professional before taking any dietary supplements, particularly if you are on any prescription medication. There are several types of omega-3 fatty acid supplements including those derived from plant sources, such as flaxseed. These are less potent than omega-3 fatty acid supplements made from fish like sardines and anchovies. Taking 1,000 to 1,200 mg of DHA and EPA (combined) is usually sufficient. Depending on the brand, a 1,000 mg fish oil capsule may contain only 300 mg of DHA plus EPA, with a dosage of four capsules daily. Look for supplements with higher concentrations of DHA plus EPA. Be aware that fish oil supplements thin your blood. If you are taking blood thinners/aspirin check with a physician before taking fish oil supplements.
- American Heart Association: Fish and Omega-3 Fatty Acids
- AM Hill et al. 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.
- MH Pedersen et al. The Effect of Dietary Fish Oil in addition to Lifestyle Counseling on Lipid Oxidation and Body Composition in Slightly Overweight Teenage Boys. J Nutr Metab. 2011; 2011: 348368.
- MayoClinic.com: Omega-3 fatty acids, fish oil, alpha-linolenic acid