This is an excellent question that is seldom asked before taking a fish oil supplement. Although most consumers take omega 3 fatty acids for general and heart health, studies show that fish oils don’t really help for those purposes (see evidence here). However, fish oils can impair the immune system and thus can be helpful for auto-immune diseases and hyperthyroidism (although I don’t advocate them).
What Do The Studies Find About Fish Oils
The headlines, news articles, and textbooks are full of positive effects of fish oil supplementation. However, if you dig a little bit deeper you will be surprised to find alternative views supported by studies. The whole suggestion of omega 3 being healthy is when omega 3 is compared to omega 6 fatty acids. Omega 6 has been flooded into the western world after the 1950’s. Omega 3 and omega 6 are generally known as polyunsaturated fatty acids (PUFA). Omega 3 & 6 are deemed essential, the human body can not make these fats endogenous (from our own body). It is generally considered that in the western diet, the consumption of omega 6 is too much, while omega 3 intake is deemed insufficient. I would like to make the case that both omega 3 and omega 6 are potentially dangerous, and every concentrated increase of intake of these fats could have (adverse) consequences. Instead of supplementing omega 3, it would make more sense to decrease the omega 6 fatty acids, most prominent in cooking oils and as substitutes for saturated fats.
Although touted as miracle health supplements, Omega 3 supplementation has a lesser-known side to them. The positive studies reporting on omega 3’s are numerous and scientific, and the consensus of the public and health care providers seem to be that there are no negative side effects of the omega 3 story, except for bad breath and an upset stomach[1]. The truth, however, shows that fish oils are amongst the most dangerous fats.
[1] http://www.webmd.com/hypertension-high-blood-pressure/guide/omega-3-fish-oil-supplements-for-high-blood-pressure