|This study is different from the average "fish oil is good for you" study and that's both refreshing and revealing. Speaking of "fresh" you got a 50/50 chance you buy fresh, not rancid fish oil.|
What? Yep, now I got your attention, right? Well, the objective of the study was to evaluate the effect of fish oil (FO) supplementation in a cohort of healthy, community-dwelling older females. Now, in contrast to your average fish oil study, the scientists did not restrict themselves to measuring the effects on blood measures of insulin, glucose, c-reactive protein, and triglycerides, though. Their primary study outcomes included the effects on the subjects' metabolic rate and substrate oxidation at rest and during exercise as well as on body composition, strength and physical function.
For the study, twenty-four healthy females (66 ± 1 yr) were recruited and randomly assigned to receive either 3g/d of EPA and DHA or a placebo (PL, olive oil) for 12 wk. Exercise measurements
were taken before and after 12 wk of supplementation and resting metabolic measures were made before and at 6 and 12 wk of supplementation.
|Figure 1: Relative changes in metabolic parameters at rest and during 30 min of exercise (Logan. 2015).|
So, how did this work? As of now we don't really know that. It is most likely that EPA and DHA modulate energy metabolism by activating one or several PPAR receptors, which may then trigger increases in the levels several protein (FAT/CD36, FABPc, UPC3) and enzymes (acyl-CoA oxidase, CPTI) which control the mitochondrial fatty acid oxidation. Additional effects on PGC-1α, which is involved in regulating the genes involved in energy metabolism, as well as in mitochondrial biogenesis and function may augment the metabolic effects of the long-chain omega-3s. Effects of which we do yet not know how they are affected by and whether they require the incorporation of DHA and EPA into the cell membrane - obviously significantly more research is necessary.Now the reason I am not going to spend time to find out, whether I or the researchers have made a mistake is that the statistically significant increase in resting metabolic rate for example amounts to 7kcal per hour, if the actual value is 2-5% lower or higher that's absolutely irrelevant. Since the same can be said for the other values, I think we all should be able to cope with any potential deviation from the actual data in the following overview I've compiled based on the (hopefully accurate) data from the tables in the full text of the study graphically in Figure 2.
|Figure 2: Graphical overview of the absolute increase in energy expenditure and fat oxidation (Logan. 2015).|
- Logan, Samantha Louise. Physical Activity and Nutrition as Modifiable Lifestyle Factors for Healthy Aging in Older Adults. Diss. The University of Guelph, 2013.