By now, many of the benefits of omega-3 fatty acids have been well established, particularly their actions as anti-inflammatory agents and their tendency to reduce the potential for blood clots by decreasing platelet aggregation (otherwise known as the tendency of platelets in the blood to clump).
Omega-3s comprise a class of fatty acids deemed essential, as critical compounds the body can't make. The other class of essential fatty acids is omega-6, abundant in nut and seed oils and the germ of grains.
Omega-6s, though essential, tend to work opposite to omega-3s in some ways, promoting inflammation and platelet stickiness. And since the ratio of omega-3 to omega-6 in the modern diet has drastically changed over the last century —favoring omega-6s, which are cheap and abundant in our food supply — nutritionists favor increasing dietary omega-3s by eating more foods such as flax, walnuts and especially fish oils. The goal is to get closer to a ratio of 2:1 or 3:1 of omega-6 to omega-3 from the current 10:1 to 20:1.
Fish oil contains omega-3s that are distinct from the flax-type omega-3s. The fatty acid molecules are longer and more bent. They are predominantly eicosepentenoic acid (EPA) and docosahexaenoic acid (DHA). These are the fatty acids abundant in organisms adapted to the cold, such as cold-water fish and cold-adapted mammals, because they keep the membranes of cells from becoming too stiff when exposed to frigid conditions. Fish obtain EPA and DHA by eating algae that have the flax-type omega-3s typical of plants.
DHA comprises about half of the fatty acids in the brain and is associated with the additional set of health benefits established for omega-3s, notably the protection of the retina, the development of the brain and the prevention of cognitive decline.
The human body can make DHA from the flax-type omega-3s — but not very efficiently. This prompted researchers to recommend obtaining DHA directly, from fish or fish oil. Cardiologists began recommending their patients take 1g per day of combined EPA/DHA. But within only a few years of a megatrend in fish oil, there arose a number of dilemmas. What about sustainability? And where do vegetarians get their omega-3s?
Last year, Whole Foods was pressured to pull from its shelves DHA derived from krill — tiny relatives of shrimp living in the Antarctic, the largest animal biomass on the planet and a potent source of DHA. The company cited sustainability concerns over the harvesting of krill.
Ironically, krill was supposed to solve the threat of overfishing resulting from the demand for DHA. But the decline of animal populations that rely on krill raised concerns over management of this natural resource, prompting the Commission for the Conservation of Antarctic Living Marine Resources to issue a report changing quotas and restricting fishing areas.
The answer was to go to the source, to algae. But not the algae that make the flax-type omega-3s; rather, the microscopic algae that make DHA itself. Cut out the middleman — or middle fish and middle krill, as it were. Raised-on-the-farm algae yield DHA that is sustainable and can carry the vegetarian label, as well as being eligible for certification as kosher and organic. Algae-derived DHA is approved for infant formulas and already is found in many applications, including fruit juices, milk, soy milk, cooking oil, sauces and tortillas.
But is algae DHA as effective at conveying the heart-healthy properties as the DHA we derive from fish oil? Many studies suggest the answer is yes, but a comprehensive review of the literature was needed.
Such was published on the first of this year in The Journal of Nutrition. Researchers from the Wellness Institute of the Cleveland Clinic, the Dept. of Nutrition and Dept. of Epidemiology at Harvard School of Public Health, Channing Laboratory, Brigham and Women's Hospital and the Harvard Medical School conducted a systematic review of randomized controlled trials published between 1996 and 2011.
The research teams examined the relation between algal DHA supplementation and cardiovascular disease risk factors, triglycerides, LDL cholesterol and HDL cholesterol. They found that supplementation with algal DHA reduced triglycerides and raised HDL-cholesterol. This was similar to what had been reported. However, algal DHA also raised concentrations of LDL-cholesterol, although the increase was accompanied by a change in the type of LDL cholesterol to the larger, less-atherogenic form. Further research is recommended because many of the studies reviewed were funded by industries.
For now, DHA from algae seems to be a sustainable, alternative source of DHA that can satisfy both the demands of consumers and the needs of vegetarians, as well as fulfilling most, if not all, the health benefits currently established with omega 3s.