Although fish is high in omega-3 it shouldn’t be included in any weight-loss diet because it contains a lot of fat, cholesterol and triglycerides. It is estimated that 60% of the calories consumed with fish come from fat which is of course incorporated into our body fat and contributes to obesity. But there are other even more important reasons why I wouldn’t include fish in a healthy diet.
We have been encouraged to consume fish because they are rich in omega-3 fatty acids. Omega-3, like omega-6, plays very important function in human organism and is called an essential fatty acid because our body can’t manufacture it, which means we have to provide it with food we eat. Fish oil has a variety of health benefits. It might be helpful in case of high blood cholesterol and triglyceride levels, obesity, depression, acne, osteoporosis, arthritis, ADHD (attention deficit hyperactivity disorder), and many other health-related problems.
It is important to know that neither humans nor fish can create their own omega-3 fatty acids. Only plants can do it. The omega-3 polyunsaturated fat found in plants is called alpha-linolenic acid (ALA) while omega-6, which is also a polyunsaturated fat, is called gamma-linolenic acid (GLA). Fish eat algae and seaweed with ALA and convert it into a long-chain omega-3 called EPA and DHA. Since, like fish, we also have to convert omega-3 from plant foods, we are told that fish is much better source of this essential fatty acid because eating fish we provide our body with already converted omega-3.
Fish, however, can’t be even regarded today as a safe food because it is very high in dangerous toxins such as mercury or dioxins (absorbed from polluted water); and second, because animal-sources of omega-3 (unlike plant sources) tend to produce a lot of deadly free oxygen radicals in human body. In addition, unlike plant foods, fish don’t have any fiber, still contain similar amount of cholesterol as meat, and are often cooked or fried with oil in a high temperature. For this reason fish may raise the blood cholesterol as quickly as pork or beef. In addition, since fish, like meat and dairy, also contain highly acidic proteins it depletes calcium from bones leading to osteoporosis and kidney stones. The best examples of this harmful effect of high-fish consumption are Eskimos who have the highest rates of osteoporosis in the world.
Since DHA is found in high concentrations in human nervous system, it is believed that omega-3 can prevent neurological diseases and improve our mental health. However, some studies demonstrated that people who consume plenty of fish have the similar risk of developing dementia as individuals whose diet does not include fish. On the other hand, those who are on a plant-based diet characterize themselves as ‘being in a better mood’ twice as often as people who eat meat on a regular basis, and are half as likely to suffer from dementia.
Fish is recommended as a healthy food especially because some fish-consuming nations such as people living in Japan are slimmer or have lower rates of heart disease than meat-eating populations. However, when we carefully investigate the diet of Japanese people we can easily conclude that their better health status can be due to the fact that they eat more unrefined plant foods, sea weeds, or sea algae such as chlorella.
It might be true that fish is less harmful than meat but it doesn’t mean it should be recommended as a health-promoting food because fish still contain a lot of cholesterol, too much of animal protein, and high concentrations of toxins such as extremely dangerous mercury which imposes a very harmful effect on our kidneys, heart, as well as the nervous and the immune systems. Mercury in fish also increases the formation of free oxygen radicals causing cancer or damaging our blood vessels and leading to heart attacks and strokes. It is also important to stress the fact that the same species of fish which are regarded as the best sources of omega-3 (EPA and DHA) usually have the highest levels of mercury! Mercury or dioxins aren’t of course the only dangerous toxins present in fish. People who consume fish on a regular basis also poison their bodies with lead, DDE, or polychlorinated biphenyls (PCBs). Some experts suggest that it takes about one whole year on a fish- and shellfish-free diet to remove mercury from human body and even over five years to rid our organism of PCBs.
In some countries fish may even increase the risk of spreading prion infections as the fish farming industries often feed fish with the leftovers from slaughterhouses which may involve the risk of transmitting prions from infected cows or other animals to fish and then to humans. In the book Foods That Fight Pain Dr. Neal Barnard wrote that „anyone who eats fish for ‘health’ reasons should think again: The flesh of fish can accumulate toxins up to 9 million times as concentrated as those in the waters that they live in, and the flesh of some sea animals, like shrimps and scallops, contains more cholesterol than beef. Fish on farms are also fed antibiotics that are passed along to humans, impairing the immune system. And according to the Centers for Disease Control and Prevention, 325,000 people get sick and some die every year in the U.S. from eating contaminated fish and other sea animals.” The same author also describes fish as “a mixture of fat and protein, seasoned with toxic chemicals.” It is obvious, therefore, that it is much wiser to consume plant sources of omega-3 because they do not contain cholesterol, mercury, dioxins, or other dangerous and harmful chemicals and substances which are found in fish.
A careful review of numerous scientific studies and thousands of articles dealing with the influence of the fish oil on human health led scientists to the conclusion that omega-3 found in fish doesn’t have clear beneficial effect on cancer, cardiovascular health or total mortality. According to the findings of this review, which appeared in 2007 in the American Journal of Cardiology, “The data supporting the inverse correlation of fish or omega-3 fatty acid (EPA and DHA) consumption and coronary heart disease are inconclusive and may be confounded by other dietary and lifestyle factors”. Also according to the results of a Dutch study published by Elizabeth E. Devore in the 2009 issue of the American Journal of Clinical Nutrition, participants who were on a high-fish diet had the same risk of developing dementia as those who never ate fish. These findings were confirmed in the same year by the study conducted by a group of Canadian researchers.
In 2013 a study results were published suggesting a correlation between omega-3 and prostate cancer. However, its methods and conclusions have been unanimously and widely condemned and criticized by respected scientific authorities as unfounded and unscientific. For example, Anthony D’Amico, professor of Radiation Oncology at Harvard Medical School said about the study that it “cannot make the conclusion that it’s trying to, because these types of studies are not cause and effect… They left out some very important risk factors for prostate cancer… The scientific strength of it is weak, at best.”
Honest analysis of scientific data leads to an obvious conclusion according to which it is not high-fish consumption nor even fish oil supplements but the unrefined plant foods such as vegetables, fruits, legumes, grains, and unsalted and unroasted seeds and nuts that make difference and reduce the risk of cancer, diabetes, cardio-vascular diseases, and many other health-related problems. It is, therefore, much better idea to consume raw unprocessed plant-based foods rich in omega-3 such as green leafy vegetables, unroasted and unsalted walnuts and seeds (especially chia seeds and flax seeds), or acai fruits. In addition to that, unlike fish, these unrefined plant foods contain a lot of fibre which also increases the level of adiponectin thus farther improving our body’s ability to control appetite and metabolism.
Unfortunately, there is a lot of controversy concerning whether plant sources of omega-3 are really beneficial. On one hand, some studies don’t seem to justify the idea that fish oil is better than plant-based sources of omega-3 as they demonstrate that humans (including children) are able to convert adequate quantities of ALA from plant foods into EPA and DHA in our bodies without any need to consume fish. Concluding the in-depth scientific literature review Professor John Langdon suggested that there is no evidence that our diets must include fish oils in order to provide adequate levels of DHA. It means that the unrefined plant products such as especially green leafy vegetables, walnuts, flax seeds, chia seeds, or chlorella and spirulina provide us with enough ALA so that we could convert it to DHA and cover our daily needs of this essential fatty acid. In his 2006 review article, Professor John H. Langdon even suggests that DHA is not an essential nutrient for the brain development of infants because pregnant women are able to efficiently convert ALA to DHA and fetuses and infants receive DHA which is released from the mother’s fat tissue and provided with breast milk.
On the other hand, some scientists, such as Nordstrom, suggested that studies according to which humans are able to convert adequate quantities of ALA from plant foods into EPA and DHA in our bodies have used doses of flax seed which were unrealistically high. In addition, according to numerous studies which attempted to assess the conversion rate of ALA (from oral flax seed supplements) to the biologically active fatty acids DHA and EPA the ALA conversion to EPA was on average less than 4%, and the conversion to DHA was a only 1%!
In addition, several studies also suggest that some humans do not have special enzyme which is required for conversion of plant-based omega-3 to EPA and DHA. For example, according to Dr. Ski Chilton, „The Omega 3 fatty acids found in flaxseed oil and fish oil are not the same and they impact our bodies differently when we consume them. The Omega 3 in flax is called Alpha-linolenic acid, or ALA, and it is a very good thing to be eating—much better than pro-inflammatory long-chain omega-6. However, most humans cannot efficiently convert ALA, a short-chain omega 3 found in plants to the potent longer-chain omega 3 bioactive, EPA and DHA, found in fish oil. The reason is simple. Humans are limited in a specific enzyme called delta-6 desaturase.” Due to the possible inefficient conversion of ALA (from plant sources) into EPA and DHA we are encouraged today to use a direct source of EPA and DHA in the form of good quality omega-3 fish oil supplements.
But even if the above conclusion is true there is a good reason to believe that if our plant based diet includes green leafy vegetables, some seeds and nuts (especially flax seed, chia seeds, hemp, pumpkin, and walnuts) and 8 to 14 (500 mg) tablets (4 – 7 grams) of spirulina and especially chlorella a day then we should cover our daily requirements for the omega-3 fatty acids.
Fortunately, there seems to be a better solution than taking fish oil supplements. It is found in the fact that although land plant products such as seeds and nuts or green leafy vegetables contain only ALA but do not have EPA and DHA yet some marine plants such as seaweeds or algae may contain both of these more efficient forms of omega-3 fatty acids. According to Dr. Julian E. Bailes from West Virginia University School of Medicine, “EPA and DHA may be obtained from a pure and sustainable source – algae, which is produced in a controlled environment, and is free of contaminants.” If you google “vegan omega 3” you will easily find such algae-based omega 3 fatty acids (such as Opti-3) offered online by different brands. They usually provide at least 200mg EPA and 400mg DHA per daily dose of 2 gelatin-free vegetarian capsules.
The only plant source of DHA is algae. Unfortunately, although some sources suggest spirulina and especially chlorella contain reliable quantities of DHA and EPA omega-3 yet none of them showed any scientific referencing. Therefore, since there is no available proof chlorella and spirulina contain DHA and EPA it’s better to use good, reliable and standardized algae-based supplements of EPA and DHA omega-3 fatty acids in order to achieve optimum speed of mental processing and CNS responsiveness, treat overweight, depression, insomnia, improve eyesight and heart health.
However, if you still think it would be a good idea to increase your daily intake of omega-3 by adding fish oil supplements make sure you choose only the best quality products as fish oils are frequently rancid and often cause unpleasant burps. Try to test your omega-3 capsules from time to time braking or biting one of them and smelling and tasting the oil. If it smells and tastes like rotting fish, discard it. A team of scientists from the New Zealand’s Crop and Food Research Institute tested the quality of fish oil capsules from many different brands and found out that a majority of the fish oils they took from the capsules to test already started to oxidize. According to the representative of the institute – Dr. Carlene McLean, “Many fish oil samples from the UK and Asian markets that we have tested contain oxidation byproducts, despite being within the sell-by date… Many fish oil supplements have a best-before date of three to four years. But fish oil starts to go off within days.” The quick degradation of the high in omega-3 fish oils is caused by their high content of the very unstable and highly unsaturated fatty acids such as EPA and DHA. As soon as the extracted from fish oil is exposed to oxygen, light, heat, or metals, the oxidation process begins. By the way, that is also the reason why fish get rotten so quickly.
It is important to avoid rotten fish oil products because instead of being beneficial to your health they actually turn to be harmful increasing risk of heart attack or stroke. Unfortunately, the same researchers from New Zealand maintain that even if the fish oil tastes and smells good it may not prove it hasn’t got rancid yet because after an initial stage of oxidation the bad smell and taste disappear in spite of the fact that the oil still continues to oxidize! For this reason some “experts” suggest we should eat fish instead of taking fish oil supplements but it is very unwise solution when we take into consideration the horrendous amount of toxins found in fish and seafood today.
Before you buy any omega-3 supplement always check the ingredients. The label must specify the content of DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) (the higher their content the better). Make sure it says that the oil underwent molecular distillation (purification from toxins). Fish oils are extracted especially from fat where the environmental toxins such as mercury, dioxins, led, or PCBs are accumulated. Look for omega-3 supplements which are free from harmful artificial preservatives and which contain vitamin E which slows down the oxidation process. It is much better if the included vitamin E is not in the form of alpha-tocopherol, which is not very potent antioxidant, but rather in the form of more expensive and much stronger antioxidant gamma-tocopherol.
Burdge, G.C, and Calder, P.C. (2005). Conversion of alpha-linolenic acid to longer-chain polyunsaturated fatty acids in human adults. Reprod. Nutr. Dev. 45, 581–597.
Burdge, G. (2004). Alpha-linolenic acid metabolism in men and women: nutritional and biological implications. Current Opinion in Clinical Nutrition and Metabolic Care, 7, 137-144.
Burdge GC, Wootton SA. (2002). Conversion of alpha-linolenic acid to eicosapentaenoic, docosapentaenoic and docosahexaenoic acids in young women. Br J Nutr, 88:411–20.
Burdge GC, Jones AE, Wootton SA. (2002). Eicosapentaenoic and docosapentaenoic acids are the principal products of a-linolenic acid metabolism in young men. Br J Nutr, 88:355–363.
Burdge GC, Finnegan YE, Minihane AM (2003). Effect of altered dietary n-3 fatty aid intake upon plasma lipid fatty acid composition, conversion of [13C]a-linolenic acid to longer-chain fatty acids and partitioning towards b-oxidation in older men. Br J Nutr, 90:311–321.
Chan JK, McDonald BE, Gerrard JM, Bruce VM, Weaver BJ, Holub BJ. (1993). Effect of dietary alpha-linolenic acid and its ratio to linoleic acid on platelet and plasma fatty acids and thrombogenesis. Lipids, 28: 811–817.
DeLany, J.P., Windhauser, M.M., Champage, C.M., and Bray, G.A. (2001). Differential oxidation of individual dietary fatty acids in humans. Am J Clin Nutr, 72, 905-911.
Dr. Ski Chilton, Flaxseed Oil vs Fish Oil, online: http://www.genesmart.com/pages/flaxseed_oil_vs_fish_oil/85.php
Emken, E.A., Adlof R.O, Duvala, S.M., Shaneb, J.M., Walkerb, P.M., and Beckerc C (1994). Effect of Triacylglycerol Structure on Absorption and Metabolism of Isotope-Labeled Palmitic and Linoleic Acids by Humans. Biochim Biophys Acta4, 1213, 277-88.
Fokkema MR, Brouwer DA, Hasperhoven MB, Martini IA, Muskiet FA. (2000). Short-term supplementation of low-dose γ -linolenic acid (GLA), α -linolenic acid (ALA), or GLA plus ALA does not augment LCP ω 3 status of Dutch vegans to an appreciable extent. Prostaglandins Leukot Essent Fatty Acids, 63(5): 287-92.
Garg ML, Thomson ABR, Clandinin MT. (1990). Interactions of saturated, n-6 and n-3 polyunsaturated fatty acids to modulate arachidonic acid Metabolism. J Lipid Res 31: 271–277.
Goyens, P.L., Spilker, M.E., Zock, P.L., Katan, M.B. and Mensink, R.P. (2006).
Conversion of -linolenic acid in humans is influenced by the absolute amounts of -linolenic acid and linoleic acid in the diet and not by their ratio Am. J. Clinical Nutrition, 84, 44 – 53.
Harper,-C-R; Edwards,-M-J; DeFilipis,-A-P; Jacobson,-T-A. (2006). Flaxseed oil increases the plasma concentrations of cardioprotective (n-3) fatty acids in humans. Journal-of-Nutrition, 136(1): 83-87.
Hussein, N., Ah-Sing, E., Wilkinson, P., Leach, C., Griffin, B.A., and Millward, D.J. (2005). Long-chain conversion of [13C] linoleic acid and alpha linolenic acid in response to marked changes in their dietary intake in men. Journal of Lipid Research Volume 46, 269-280.
Layne KS, Goh YK, Jumpsen JA, Ryan EA, Chow P, Clandinin MT. (1996). Normal subjects consuming physiological levels of 18:3(n-3) and 20:5 (n-3) from flaxseed or fish oils have characteristic differences in plasma lipid and lipoprotein fatty acid levels. J Nutr 126: 2130–2140.
Langdon JH. Has an aquatic diet been necessary for hominin brain evolution and functional development? Br J Nutr. 2006 Jul;96(1):7-17. Review.
Nordstrom, D.C.E, Honkanen, E.A., Antila, N.E., C. Friman Y.T. and Konttinen (1995). Alpha-linolenic acid in the treatment of rheumatoid arthritis. A double.blind, placebo-controlled and randomized study: flaxseed vs. safflower seed. Rheumatol Int, 14, 231-234.
Pawlosky RJ, Hibbeln JR, Novotny JA, Salem N Jr. (2001). Physiological compartmental analysis of α-linolenic acid metabolism in adult humans. J Lipid Res 42: 1257–1265.
Petra L. L. Goyens, Mary E. Spilker,Peter L. Zock, Martijn B. Katan, and Ronald P. (2005). Mensink Alpha-linolenic acid conversion after longer term intake of multiple tracer boluses Journal of Lipid Research Volume 46, 1474-1483.
Sprecher, H. (2002). The roles of anabolic and catabolic reactions in the synthesis and recycling of polyunsaturated fatty acids. Prostaglandins Leukot Essent Fatty Acids, 67-79083.
Tarpila S, Aro A, Salminen I, Tarpila A, Kleemola P, Akkila J, Adlercreutz H. (2002). The effect of flaxseed supplementation in processed foods on serum fatty acids and enterolactone.Eur J Clin Nutr, 56(2):157-65.
Uauy, R., Hoffman, D.R., Peirano, P., Birch, E.E. (2001). Essential fatty acids in visual and brain development. Lipids, 36, 885-895.
Vermunt SHF, Mensink RP, Simonis MMG, Hornstra G. (2000). Effects of dietary α-linolenic acid on the conversion and oxidation of 13C-α-linolenic acid. Lipids 35: 137–142.
Craig Cooper, July 12, 2013. “Omega-3 Prostate Cancer Study Flawed – Don’t Believe All You Read”. Online: