Not all fish oils are created equal.
The main, and most popular, source of DHA and EPA is said to be fish oil. However, not all fish oils are good sources of these fatty acids. The highest levels come from salmon, tuna, sardines, trout, and corvina1, 2, 3 but many fish oil supplements contain only oils from one of these (sardines). The rest is made up of the oils from such cheaper and lesser fish as mackerel and anchovies. Some manufacturers state it is because they are lower in pollutants, but pollutants are found in all oily fish.
Fish oil for supplements comes mainly from reduction fisheries in Peru and Chile. Europe, Africa, and the US make up the rest of the market. Fish caught for reduction are mainly anchovies, sardines, mackerel, and menhaden used specifically for fish oil, fishmeal, and animal feed.4
Fish oil supplements can come in several forms: natural or chemically modified and can be stable or unstable. Natural fish oils have a maximum concentration of 38%. Anything higher than that has been chemically modified and come in three different types: those containing triglycerides where the fatty acids have been chemically changed; those that contain ethyl esters; and those that have free fatty acids.5 Natural fish oil has the balance of all the fatty acids in the fish. Although chemically modified supplements may have higher concentrations of DHA and EPA, they have not proven themselves to be more effective.
Obtaining DHA and EPA from canned fish is not a good alternative either. While canned fish is said to contain some EFAs, much is lost in the extensive processing. In addition, the natural fish oil, where the essential fatty acids are located, is removed through pre-cooking and replaced6 by cheaper hydrogenated vegetable oils, usually from olives, sunflower, or soy.
As we saw in Reason #1, canned fish also contains pollutants, including mercury as well as other substances not on the label, but allowed by governmental regulations. Another problem not readily seen is the amount of canned fish one would have to eat to obtain the necessary DHA and EPA content. For example, the EPA/DHA content of a 3 g serving of tuna (packed in water) is roughly 0.24 percent. To fulfil the recommended one gram daily requirement, one would have to eat 12 more of these.7
Also previously mentioned, farmed fish contain hardly any omega-3 fatty acids unless they are fed significant amounts fish scraps. Since most are fed vegetable proteins, the valuable omega-3 content will be next to nil compared to ocean fish that feed on plankton. Interestingly, plankton found in colder waters contains more omega-3s than that found in warmer waters.
Hydrogenated or partially hydrogenated fish oil is popular in such countries as Holland, Norway, Great Britain, Chile, Peru, and South Africa. These are not only a source of the harmful trans-fats, but also a poor source of the omega-3 fatty acids, mainly because the hydrogenation process all but eliminates any EPA and DHA content.8, 9
A report10 published by ConsumerLab found that, of the 41 brands of Omega-3 fatty acid fish oil supplements tested, none had detectable levels of mercury; that is, less than 1.5 parts per billion (ppb) and no unsafe levels of PCBs (polychlorinated biphenyls) what is deemed a safe level is not determined since the definition fluctuates among organizations.11 For example, the biggest gap is with PCB levels. Not surprisingly, FDA standards are the least stringent (2,000 parts per billion (ppb) while the State of California has the most stringent standard (90 ppb).
The report goes on to say that one brand of fish oil supplement was spoiled and some fell short of the amount of EPA or DHA stated on the label with the worst containing only 53% of its claimed EPA content. Although this product was marketed for use by pets, it was also sold for human use.
Another study12 was done by a group called Environmental Defense. They contacted 75 companies who produce fish oil supplements commonly found in supermarkets, pharmacies, and health food stores and asked them three questions.
- Do you purify your fish oil to reduce or remove environmental contaminants?
- What methods do you use to purify your fish oil?
- What standards do you comply with regarding acceptable levels of contaminants?
Environmental Defense also requested information on three contaminants: mercury, PCBs, and dioxins since these three are found in the majority of consumption advisories for fish caught in the United States. Although most companies adhered to a strict standard of contaminant removal, some were less than forthcoming with their information. Therefore, consumers are admonished to be knowledgeable about the brands they are using and not just with fish oil supplements.
Pharmaceutical grade fish oil is a term used to separate unscrupulous fish oil supplement manufacturers from those trying to offer a decent product. However, since there are no set standards for this term, it didnt take long before it was picked up and widely used. To some, pharmaceutical grade means a concentrated potency of EPA and DHA in their products, while to others it means a lack of impurities and contaminants.13
Tran goes on to say that most fish oil supplements found in grocery or drug stores apparently do not even meet the standards of this open-ended definition. According to some manufacturers, it takes roughly 100 gallons of health-food grade fish oil to produce one gallon of pharmaceutical-grade fish oil.14 But even this is not set in stone. It just depends on the ethics of any particular manufacturer. Dr. Barry Sears, who supposedly was the first to coin the term pharmaceutical-grade, has become so disgusted with it all, that he changed the name of his pharmaceutical-grade product to ultra-refined.15
According to a consumer report by International Fish Oil Standards,16 standards of quality have been raised to a 5-star rating system that will show better levels of quality and purity. Although this particular report lists various products that meet their consumer ready standards, nothing was stated as to whether any or all received the full 5-star rating. To be fair, it is these products that try to maintain high quality standards.
- 1Nettleton. 1995. Omega-3 Fatty Acids and Health. New York: Chapman and Hall.
- 2Andrade, Rubira, Matsushita, and Souza. 1995. “Omega-3 fatty acids in freshwater fish from South Brazil.” Journal of the American Oil Chemists Society 72(10):1207-10.
- 3Tornaritis, Peraki, Georgulli, Kafatos, Charalambbakis, Divanack, Kentouri, Yiannopoulos, Frenaritou, and Argyrides. 1994. “Fatty acid composition and total fat content of eight species of Mediterranean fish.” International Journal of Food Sciences and Nutrition 45:135-39.
- 4“Environmental Defence.” http://www.oceansalive.org/eat.cfm?subnav=article&contentID=4362
- 5Saldeen. 2002. “Fish Oil and Health. Positive Health.”
- 6“EPA fish processing methods.” http://www.epa.gov/ttn/chief/ap42/ch09/final/c9s13-1.pdf
- 7Adapted from the USDA Nutrient Data Laboratory http://www.ars.usda.gov/main/site_main.htm?modecode=12354500
- 8Molketin and Precht. 1995. “Determination of trans-octadecenoic acids in German margarines, shortenings, cooking and dietary fats” by Ag. TLC/GC. Ernährungswiss 34:314-17.
- 9Innis and King. 1999. “Trans-fatty acids in human milk are inversely associated with concentrations of essential all-cis-6 and n-3 fatty acids in plasma lipids of breast-fed infants.” American Journal of Clinical Nutrition 70:383-90.
- 11Environmental Defence. “How safe are fish oil supplements?”http://www.environmentaldefense.org/article.cfm?contentid=4362
- 12Environmental Defence. Fish Oil Supplements: Is The Brand You’re Taking Safe? http://www.oceansalive.org/eat.cfm?subnav=fishoil&sort=Rating
- 13Tran. Mar, 2005. Fish oil supplements: finding the one thats right for you. Better Nutrition. http://www.findarticles.com/p/articles/mi_m0FKA/is_3_67/ai_n11832856
- 14Storer. Pharmaceutical Grade Fish Oil – Why Is It Different?
- 15Dr. Barry Sears.
- 16IFOS (International Fish Oil Standards). University of Guelph, Canada. ;
This page was researched in November 2005.