Omega-3 fatty acids have become all the rage recently, and for good reason. Significant evidence supports their benefit for a wide range of medical conditions including depression, heart disease, rheumatoid arthritis, psoriasis, inflammatory bowel disease, and a number of other conditions. So doctors and naturopaths have started advising that we get our share of this important nutrient. The fish industry has also capitalized on this new information since certain fish are rich in omega-3 fatty acids. People have been encouraged to eat more fish, and supplements with fish oil have been marketed to benefit people with heart disease and other conditions.
Unfortunately there are problems with getting our omega-3 fatty acids from fish. An obvious concern is fact that the cholesterol per serving is almost the same as from any other meat source. Also as with other meat sources, most fish are high in saturated fat which encourages the body to make more cholesterol. Another concern is that fish concentrate (up to a million times even in only mildly polluted water) and contain chemicals such as mercury, pesticides, chlorinated hydrocarbons, and dioxin, and also can contain PCBs, various heavy metals, petroleum hydrocarbons, halogenated organic compounds, and lead. For this reason pregnant women are advised by the FDA against eating certain fish altogether (shark, king mackerel, tilefish due to high levels of mercury) and advised to limit intake of other fish with lower content of mercury to 12 ounces per week or only 6 ounces of albacore tuna per week (other fish: shrimp, canned light tuna, salmon, pollock, catfish).
But do we really need to get our omega-3’s from fish? Should we settle for low levels of mercury and other toxin exposure when we could avoid all the toxins in fish? Well, let me tell you a little secret. The omega-3 fatty acids that you get from fish are second hand omega-3’s. In other words, the fish contain omega-3 fatty acids because they ate plants that contain them. Alpha-linolenic acid (ALA) is the precursor found in plants which our bodies break down into EPA (eicosapentaenoic acid) and DHA (end products found in fish). So the good news is that we can go to the source instead of eating it second hand in the form of a high cholesterol, polluted animal fat package (animal fat in general is linked to cancer and atherosclerosis as well as obesity and related diseases). Studies have shown an expected significant rise in EPA in the body after a given amount of alpha-linolenic acid is ingested in the form of a plant product.
Unfortunately some sources insist that you must get this nutrient from fish. It is true that current studies show that humans only break down about 5-6% of the linolenic acid into EPA which is another reason that fish consumption is being urged upon us. However, who is to say how much of this EPA we really need? This advice is also skewed based on the study population used to produce the data. The amount of EPA that we are advised to get from fish is based on the amount that has been shown to benefit heart disease patients, people eating a high fat, high cholesterol diet, and some studies have shown up to 50% decrease in heart disease deaths (Dutch study of 852 men). However, studies have also shown that individuals on a total vegetarian diet decrease risk of heart disease deaths up to 86%. Thus there is more benefit from eating a total vegetarian diet than from eating fish. Therefore for those who insist on eating a diet rich in fat and cholesterol, fish may be a good addition to their diet or perhaps a substitution for other meats. However for someone already on a good diet adding fish could actually increase the risk of heart disease by increasing fat and cholesterol levels as seen in a Harvard study of 44,895 men showing that the addition of fish actually increased the risk of heart disease. So the amount of omega-3 fatty acids that we need is really unknown, but it is clear that getting them from a source with high fat and high cholesterol is not ideal. It also is clear that our bodies break down ALA to EPA. So it seems that the best place we can get these nutrients is from our everyday foods: flaxseed oil and flaxseed, english walnuts, soybean oil, canned spinach, as well as smaller amounts in more common foods such as beans, banana, apple, bread, and potatoes.
Over the years we have seen time and again that nutrients, when given in isolated, supplement form, can actually be harmful because they are more concentrated and interact differently in the body when they are just poured in instead of allowing the body to regulate their use, distribution, and breakdown. Take for example studies on vitamin E. In the setting of a vitamin E-rich diet, vitamin E seemed to decrease risk of lung cancer, but when given in supplement form it actually increased the risk of lung cancer. There have been many other similar examples.
So is this vitamin actually bad for us? Of course not. It is very important, but the format in which it is delivered is also very important. So when we supplement with fish oil, which is already broken down by the fish into EPA, we are supplementing something that is not in its natural form. We already know that there is risk of too much EPA leading to hemorrhage and thus stroke. So why don’t we get back to nature instead and eat the whole food and let our bodies choose to break it down as it is needed instead of risk having some negative effect because of the form we choose to ingest. Also, why seek a necessary nutrient in a cholesterol rich, polluted package when we can get that nutrient directly from the same source that the fish gets it from? Let’s go to the source: plants.
References:
Proof Positive. Neil Nedley, MD.
- Kromhout D, Bosschieter EB, de Lezenne Coulander C. The inverse relation between fish consumption and 20-year mortality from coronary heart disease. N Engl J Med 1985 May 9;312(19):1205-1209.
- Phillips R, Lemon F, Kuzma J. Coronary heart disease mortality among Seventh-Day Adventists with differing dietary habits. Am J Clin Nutr 1978 Oct;31(10 Suppl):S191-S198.
- Ascherio A, Rimm EB, et al. Dietary intake of marine n-3 fatty acids, fish intake, and the risk of coronary disease among men. N Engl J Med 1995 Apr 13;332(15):977-982.