If you only read the headline you’ll have the gist of this post. But I am writing this post because I have clients who get all twitter-pattered, some even get the vapors, when they read on other sites from fitness experts that mega-dosing fish oil (up to 30g per day) may increase metabolism by 400 CALORIES A DAY! Yay! We get three more pieces of bread a day! Well, not so fast.
I’ve got comments for each section separated by a
It’s one thing to talk shit and say that mega-dosing fish oil will increase metabolic rate by 400 cals or so. It’s quite another to actually have good, repeated data to support it.
If you want to skip all the gobbledy gook below know that fish oil has a host of benefits relating to cardiovascular health and anti-inflammatory properties. Fish oil contains omega-3 fats and omega-3 fats are essential for good health. I don’t recommend, for most people, that they consume more than about 3g/day of fish oil because of the increased bleeding risk. And I certainly will not say that if you mega-dose or even moderately dose that you are going to get a 100, 200, 300 or 400 calorie per day boost in your metabolic rate – no way in HELL. One study you’ll see below does show a 17 calorie per day boost with fish-oil users – now THAT I can believe but whoop-dee-doo folks – 17 calories a day.
Here’s what one expert posted to support his position that high-dose fish oil can boost metabolism some time ago
EFFECTS OF VARYING DOSES OF FISH OIL SUPPLEMENTATION ON RESTING METABOLIC RATE AND BODY COMPOSITION
E.E. Noreen, R.J. Petrella, FACSM, P.W.R. Lemon, FACSM. (Sponsor: P.W.R. Lemon)
University of Western Ontario, London ON
Several studies have shown that rodents accumulate less body fat when fed a diet rich in fish oil (FO) when compared to an isoenergetic diet rich in other fat. However, little is known about this effect in humans. PURPOSE: 1) To determine the effect of supplemental FO on resting metabolic rate (RMR) and body composition and 2) To determine if there is a difference in response to varying doses of FO. METHODS: 32 healthy men and women (50+16 y, mean+SD) participated in this study. Baseline measurements were made following an overnight fast. Body composition was assessed by whole body densitometry using air displacement. RMR was measured by indirect calorimetry using a face mask. Blood samples were analyzed for glucose, triglycerides (TG), and insulin. 24h urine creatinine (CR) was measured. Subjects were matched for fat free mass and assigned to one of four groups: Safflower oil (SO) – 9g/d; Low FO (LFO) – 3g/d concentrated FO supplying 900 mg eicosapentaenoic acid (EPA) and 600 mg docosahexaenoic acid (DHA); Medium FO (MFO) – 6g/d FO supplying 1.8g EPA and 1.2g DHA per day; High FO (HFO) – 9g/d FO supplying 2.7g EPA and 1.8g DHA. All tests were repeated following 28d of treatment. RESULTS: RMR increased in all FO groups following supplementation (LFO 488+199 kcal/d, p<0.05; mean+SEM, MFO 196+48 kcal/d, p<0.1, HFO 141+83 kcal/d, p>0.1) and decreased in the SO (-65+77, p>0.1). Urinary CR excretion increased in all FO groups (LFO 30+80 mg/d, p>0.1, MFO 60+50 mg/d, p>0.1, HFO 200+100 mg/d p<0.1) and decreased in the SO (-260 +160 mg/d, p<0.05). Serum TG decreased significantly in all FO (p<0.05), with no change in SO. Body composition changes were not significant. CONCLUSION: 28d of FO supplementation increases RMR in humans; however, lean mass changes do not appear to be responsible.
DAVID SAYS: It appears this study was presented as a slide presentation back in 2004 I believe. It’s not listed in PUBMED even though you’ll find a link to the journal it’s attached to which is
Medicine & Science in Sports & Exercise
May 2003 Volume 35 Issue 5 pp: S248
This piece of research indicates that the LOW-DOSE fish oil group had the biggest boost in resting metabolic rate (RMR) with 3g of fish oil providing a 488 kcal/day boost in metabolism.
The MEDIUM-dose group had less metabolic rate increase and the HIGH-dose group had even less. See the abstract above for MFO and HFO numbers. It’s pretty clear.
What I don’t see is this group sucking down 30 grams a day of actual EPA and DHA or even 30 grams per day of the oil containing EPA and DHA. I see, 3g (low dose), 6g (medium dose) and 9g (high dose).
HERE’S ANOTHER STUDY FOR FUN READING – JUST THE ABSTRACT
Effects of omega-3 supplementation in combination with diet and exercise on weight loss and body composition.
DeFina LF, Marcoux LG, Devers SM, Cleaver JP, Willis BL.
The Cooper Institute, Dallas, TX 75230, USA. email@example.com
In addition to the metabolic and cardiovascular benefits of omega-3 (n-3) fatty acids, several studies have suggested an added weight loss-enhancing benefit to this supplement.
The objective was to assess whether supplemental omega-3 fatty acids in conjunction with diet and exercise augment weight loss over a 6-mo period.
In a single-institution, placebo-controlled, randomized clinical trial, 128 individuals with a body mass index (in kg/m(2)) between 26 and 40 were assigned to receive 5 omega-3 [3.0 g eicosapentaenoic acid (EPA) plus docosahexaenoic acid (DHA) at a 5:1 ratio (EPA:DHA)] or placebo capsules daily in conjunction with lifestyle modification. The primary endpoint was weight loss; secondary endpoints included metabolic and psychometric variables. Analyses were by intention-to-treat.
Overweight and obese individuals were assigned to the omega-3 arm (n = 64) or to the placebo arm (n = 64). Subjects in both arms received dietary and exercise counseling. Eighty-one individuals completed the 24-wk study, and the dropout rate was 27%. Subjects in both arms lost an average of >5% of their body weight. No significant differences in weight loss were observed between the omega-3 (-5.2 kg; 95% CI: -6.0, -4.4 kg) and placebo (-5.8 kg; 95% CI: -6.7, -5.1 kg) arms. The absolute mean (±SEM) change difference was 0.61 ± 0.58 kg (P = 0.29). In addition, no significant differences in the other factors assessed were observed.
Omega-3 fatty acids were not effective as an adjunct for weight loss in this otherwise healthy, overweight population.
DAVID SAYS: OOPSIE – Omega-3 not effective in this study. Doesn’t mean I don’t still believe in using them. I do, use them everyday I can remember, but touting their benefit especially at 30g dosing recommendations is minimally misleading and at the other end reckless.
In this study showing fish oil to have an effect on body fat the subjects consumed their fish oil as TUNA. Again, I don’t see super high-mega dosing of fish oil being used.
Combining fish-oil supplements with regular aerobic exercise improves body composition and cardiovascular disease risk factors.
Hill AM, Buckley JD, Murphy KJ, Howe PR.
Nutritional Physiology Research Centre and the Australian Technology Network Centre for Metabolic Fitness, University of South Australia, Adelaide, Australia.
Regular exercise and consuming long-chain n-3 fatty acids (FAs) from fish or fish oil can independently improve cardiovascular and metabolic health, but combining these lifestyle modifications may be more effective than either treatment alone.
We examined the individual and combined effects of n-3 FA supplements and regular exercise on body composition and cardiovascular health.
Overweight volunteers [body mass index (BMI; in kg/m(2)): >25] with high blood pressure, cholesterol, or triacylglycerols were randomly assigned to one of the following interventions: fish oil (FO), FO and exercise (FOX), sunflower oil (SO; control), or SO and exercise (SOX). Subjects consumed 6 g tuna FO/d ( approximately 1.9 g n-3 FA) or 6 g SO/d. The exercise groups walked 3 d/wk for 45 min at 75% age-predicted maximal heart rate. Plasma lipids, blood pressure, and arterial function were assessed at 0, 6, and 12 wk. Body composition was assessed by dual-energy X-ray absorptiometry at 0 and 12 wk only.
FO supplementation lowered triacylglycerols, increased HDL cholesterol, and improved endothelium-dependent arterial vasodilation (P<0.05). Exercise improved arterial compliance (P<0.05). Both fish oil and exercise independently reduced body fat (P<0.05).
FO supplements and regular exercise both reduce body fat and improve cardiovascular and metabolic health. Increasing intake of n-3 FAs could be a useful adjunct to exercise programs aimed at improving body composition and decreasing cardiovascular disease risk.
In this study – same author as the first one I believe it sounds AWESOME when you look at the abstract. I mean, fish oil increased lean body mass, reduced fat mass – friggin AWESOME! But here’s the deal – when you actually look at the full study you see that the pre- and post-difference in resting metabolic rate for the fish oil users went from 1335 kcal/day to 1352 kcal/day – about 17 calories per day.
17 calories per day – about the value of 2-3 almonds. Not 2-3 OUNCES of almonds but 2-3 friggin almonds. Wow! Get out of my way folks I gots to get me some mega-dosing fish oil. What a joke.
Effects of supplemental fish oil on resting metabolic rate, body composition, and salivary cortisol in healthy adults.
Noreen EE, Sass MJ, Crowe ML, Pabon VA, Brandauer J, Averill LK.
Department of Health Sciences, Gettysburg College, Gettysburg Pennsylvania, USA. firstname.lastname@example.org.
To determine the effects of supplemental fish oil (FO) on resting metabolic rate (RMR), body composition, and cortisol production in healthy adults.
A total of 44 men and women (34 ± 13y, mean+SD) participated in the study. All testing was performed first thing in the morning following an overnight fast. Baseline measurements of RMR were measured using indirect calorimetry using a facemask, and body composition was measured using air displacement plethysmography. Saliva was collected via passive drool and analyzed for cortisol concentration using ELISA. Following baseline testing, subjects were randomly assigned in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO); or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6 wk of treatment. Pre to post differences were analyzed using a treatment X time repeated measures ANOVA, and correlations were analyzed using Pearson’s r.
Compared to the SO group, there was a significant increase in fat free mass following treatment with FO (FO = +0.5 ± 0.5 kg, SO = -0.1 ± 1.2 kg, p = 0.03), a significant reduction in fat mass (FO = -0.5 ± 1.3 kg, SO = +0.2 ± 1.2 kg, p = 0.04), and a tendency for a decrease in body fat percentage (FO = -0.4 ± 1.3% body fat, SO = +0. 3 ± 1.5% body fat, p = 0.08). No significant differences were observed for body mass (FO = 0.0 ± 0.9 kg, SO = +0.2 ± 0.8 kg), RMR (FO = +17 ± 260 kcal, SO = -62 ± 184 kcal) or respiratory exchange ratio (FO = -0.02 ± 0.09, SO = +0.02 ± 0.05). There was a tendency for salivary cortisol to decrease in the FO group (FO = -0.064 ± 0.142 μg/dL, SO = +0.016 ± 0.272 μg/dL, p = 0.11). There was a significant correlation in the FO group between change in cortisol and change in fat free mass (r = -0.504, p = 0.02) and fat mass (r = 0.661, p = 0.001).
6 wk of supplementation with FO significantly increased lean mass and decreased fat mass. These changes were significantly correlated with a reduction in salivary cortisol following FO treatment.
The human body can synthesize all the fatty acids it needs from carbohydrate, fat, or protein except for two – linoleic and linolenic acid. Both are polyunsaturated fatty acids and cannot be made from other substances in the body. They must be obtained from food and
therefore arecalled essential. Linoleic and linolenic acids are found in small amounts in plant and fish oils. From both of these essential fats the body makes important hormone-like substances that regulate a wide range of body functions including: blood pressure, clot formation, blood lipid concentration, the immune response, the inflammation response to injury, and many others. These two essential fats also serve as structural components of cell membranes.
“The cell membrane is the outermost limit of a cell, but it is more than a simple boundary surrounding the cellular contents. It is an actively functioning part of the living material, and many important metabolic reactions take place on its surfaces.”
If all cellular systems aren’t working optimally, then your fat loss efforts will be hindered. The semi-permeable cell membrane is composed of fats. If you don’t provide your body with essential fatty acids (good fats) then improper or unhealthy fats will displace the good fats in cell walls and cells won’t function optimally. Your immune system can become compromised, recovery from exercise will be hindered, and overall health, energy and vitality will suffer.
Linoleic and Linolenic Acid
Linoleic acid is an omega-6 fatty acid found in the seeds of plants and in the oils harvested from the seeds. Any diet that contains vegetable oils, seeds, nuts, and whole-grain foods provides enough linoleic acid to meet the body’s needs. Even though vegetable oils are high in omega-6 fatty acids, I do not recommend using them for cooking. Research indicates the overconsumption of these polyunsaturated fats is the most likely to promote cancer.
Linolenic acid belongs to a family of polyunsaturated fatty acids known as omega-3 fatty acids. The typical American diet is heavy in omega-6 fatty acids and light on omega-3 fatty acids. The importance of omega-3 fatty acids has only recently been recognized. Researchers now know that omega-3 fatty acids are essential for normal growth and development, and that they may play an important role in the prevention and treatment of heart disease, hypertension, arthritis, and cancer. The best sources of linolenic acid are fatty cold-water fish (e.g., Herring, Salmon, Mackerel) and flax.
CONCLUSION: Fish oils are concentrated sources of omega-3 fatty acids. Many people who don’t regularly eat fatty, cold-water fish, use dietary supplements containing flax oil, fish oil or popular blends to insure adequate omega-3 essential fatty acids. If you are not a regular consumer (at least 2-3 servings per week) of fish, then I believe that moderate supplementation with a combination of fish and or flax is intelligent and healthy for most Lifestylers.