Why I Don’t Take Fish Oil

I have nev­er liked seafood. It smells bad to me. I’m so sen­si­tive to that smell that I don’t even like sit­ting next to some­one who is eat­ing seafood. Even the idea of tak­ing a fish oil cap­sule makes me queasy because I don’t want to end up tast­ing or smelling fish if I belch. So I was great­ly relieved to dis­cov­er that human beings don’t need to eat fish or take fish oil! The dis­eases that fish oil is sup­posed to help pre­vent are rare to nonex­is­tent among peo­ple who eat a low-fat, plant-based diet. Also, a recent study showed that veg­ans (peo­ple who don’t eat any ani­mal foods) had plen­ty of the long-chain omega 3 fat­ty acids in their blood­stream, even though they weren’t eat­ing any of the long-chain omega 3 fat­ty acids and were eat­ing rel­a­tive­ly lit­tle of their pre­cur­sor, alpha-linolenic acid. (For an expla­na­tion of the essen­tial fat­ty acids, click here.)

Fish oil is fat from a fish. An oil is just a fat that is liq­uid at room tem­per­a­ture. The fat from fish tends to stay liq­uid at room tem­per­a­ture because it is rich in polyun­sat­u­rat­ed fat­ty acids. (For an expla­na­tion of the dif­fer­ent kinds of fats, click here. Fish oil con­tains a lot of omega 3 fat­ty acids, which are much less plen­ti­ful than omega 6 fat­ty acids in the stan­dard Amer­i­can diet. Like humans, how­ev­er, fish CANNOT make their own sup­ply of omega 3 fat­ty acids. The omega 3 fat­ty acids in fish came from the plants at the bot­tom of their food chain.

Your body can make all the sat­u­rat­ed and monoun­sat­u­rat­ed fat­ty acids that it needs. How­ev­er, it can’t make omega 6 or omega 3 fat­ty acids. The only two fat­ty acids that are con­sid­ered essen­tial (which means that they have to be found ready-made in your food) in human nutri­tion are an omega 6 fat­ty acid called linole­ic acid and an omega 3 fat­ty acid called alpha-linolenic acid. How­ev­er, it’s extreme­ly rare to find any­one with a real dietary defi­cien­cy of either one. It’s the sort of thing that hap­pens only in tube-fed patients who are being fed fat fat-free solu­tions or being giv­en an unbal­anced fat sup­ple­ment. Their needs for these essen­tial fat­ty acids can be met by rub­bing a small amount of veg­etable oil on their skin.

Your body uses the omega 6 and omega 3 fat­ty acids as raw mate­ri­als to make eicosanoids and leukotrienes, which are sig­nal­ing mol­e­cules that play impor­tant roles in inflam­ma­tion and immu­ni­ty. These mol­e­cules also serve as mes­sen­gers in the ner­vous sys­tem. Because the eicosanoids that are made from omega 6 fat­ty acids inter­act with the ones made from omega 3 fat­ty acids, it’s prob­a­bly impor­tant to get a rea­son­able bal­ance between these two kinds of fat­ty acid in the diet. The most sen­si­ble way to do this is to cut way back on fat con­sump­tion and eat lots of fresh veg­eta­bles. For an extra mar­gin of safe­ty, you can add a spoon­ful of ground flaxseed to your cere­al in the morn­ing. Flaxseed is a good source of alpha-linolenic acid.

The omega 3 fat­ty acid that is found in plants is alpha-linolenic acid. Like fish, human beings can length­en the car­bon chain of alpha-linolenic acid to pro­duce oth­er fat­ty acids that the human body needs: docosa­hexaenoic acid (DHA) and eicos­apen­taenoic acid (EPA). DHA is found in the cell mem­branes in the ner­vous sys­tem, includ­ing the reti­na of the eye. EPA is used to make some impor­tant eicosanoids that help to mod­er­ate the effects of the eicosanoids that are made from omega 6 fat­ty acids.

The Food and Nutri­tion Board of the Nation­al Acad­e­my of Sci­ences does not con­sid­er DHA or EPA to be essen­tial nutri­ents, which means that those fat­ty acids don’t have to be found in your food. For a tech­ni­cal dis­cus­sion of which fat­ty acids are essen­tial and how much of each you need, see this report from the Food and Nutri­tion Board of the Nation­al Acad­e­my of Sci­ences: https://www.nap.edu/read/10490/chapter/10

Because of the com­pli­cat­ed roles that the essen­tial fat­ty acids and DHA and EPA play in the immune and ner­vous sys­tem, there’s been a lot of inter­est in using sup­ple­ments of these fat­ty acids as drugs. As with any drug treat­ment, the deci­sion of how and when to use these sup­ple­ments should be based on clin­i­cal tri­als, when­ev­er pos­si­ble. Since most of the dis­eases that fish oil is being used to treat are rare in pop­u­la­tions that eat a low-fat, plant-based diet, it makes sense to try cor­rect­ing the diet before using fish oil sup­ple­ments.

It is the­o­ret­i­cal­ly pos­si­ble that some peo­ple, espe­cial­ly those who have trou­ble absorb­ing fat from their food or who have a rare meta­bol­ic dis­or­der, might ben­e­fit from tak­ing some form of fat sup­ple­ment. How­ev­er, many peo­ple refuse for var­i­ous rea­sons to use fish prod­ucts. For­tu­nate­ly for those peo­ple, DHA and EPA sup­ple­ments made from marine algae are avail­able.