Fish oils are often touted as panaceas for a variety of health conditions, and supplementation is often described as having a positive impact on our metabolic health. In this MotivatingMax article we explore the power of these good fats and consider the evidence base out there.
Fish do not produce omega-3 fatty acids themselves, rather they accumulate them in their tissues by eating either microalgae or prey fish (that have, in turn accumulated omega-3 fatty acids). Microalgae are also known to provide a high payload of antioxidants such as iodide and selenium. The combination of anti-oxidants and fish oils is apt as the former protects the fragile polyunsaturated lipids from oxidative damage.
What kinds of fish are highest in Omega-3 fatty acids, the fish oils that are generally held to be the most beneficial for our metabolism? The answer is the fatter, predatory fish such as swordfish, tilefish, sharks, and albacore tuna.
The drawback to consuming the meat of these fish is that, owing to their privileged position atop the food chain, these species can also accumulate toxic substances through a process known as biomagnification. This has led several health bodies, including America’s Food and Drug Administration to propose limiting the consumption of such species due to potentially damaging levels of substances such as mercury, dioxin, PCBs and chlordane.
What beneficial effects follow from consuming the omega-3 fatty acids in fish oil? Over the last decade research has pointed to the ability of these fats to curb or aid in the prevention of various conditions that entail some form of inflammation; examples being hypertriglyceridemia and possibly heart disease. There are several mechanisms at play here but the most likely pathway is blood thinning that prevents clotting. At present there is mixed evidence for the utility of fish oils in the treatment of psychological conditions such as clinical depression and anxiety.
In these cases, the explanation for the findings is unclear. We think the best possible account is that a constituent of fish oils serves to upregulate the brain’s neuroreceptors; particularly those that are involved in the serotonin pathways. The best evidence linking fish oils with weight loss actually comes from animal studies: In one example (see http://www.ncbi.nlm.nih.gov/pubmed/14686961) mice were fed a variety of different fats as part of a calories controlled diet.
When fat type was manipulated toward omega 3 oils (meaning a higher percentage of energy came from this source) then improvements in metabolic health were seen that proved similar to those experience by mice on a low fat diet. Which all goes to show, it’s not how much fat you eat… but what kind!
In conclusion we believe there is sufficient evidence to support the consumption of a fish meal that is high in Omega-3 at least once per week. Moderate supplementation with fish oils may also prove beneficial to some although there is considerable debate over the use of alternate polyunsaturated fats or even “healthy” saturated fats such as coconut oil.