My mother and my father are soldiers. Every morning, in an effort to prevent old age and dry rot, they pour in a tablespoon of greasy, stinky fish oil. This is done without any obvious signs of distress – clearly they belong to a more stoic generation.
Fish oils – or more specifically, the omega-3 long-chain polyunsaturated fatty acids (n-3 PUFAs) found in fish oils – have been associated with cognitive performance. The idea of cognitive lubrication has proven to be very popular. However, for some of us, the thought of smothering fish oil in its liquid form is repugnant.
This is where fish oil capsules come in. On the surface, they seem like the perfect solution. Fish oil remains safely trapped in its hard shell until it passes through the stomach and into the upper intestine. Once there, the capsule breaks down to allow the Fish Brain Lubricant to be released.
There is only one problem. New to research led by Benjamin Albert at the University of Auckland in New Zealand shows that the quality of over-the-counter fish oil capsules is pretty poor.
Albert and his team purchased 32 different brands of fish oil capsules and measured them for levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), supposedly the “good” n-3 PUFAs responsible for brain gains. They found that 69% (29 of 32 tested) had lower levels of EPA and DHA than stated on the label. As an interesting note, the more expensive capsules were more accurately labeled for EPA and DHA levels.

To achieve EPA and DHA levels as low as advertised, either the freshly isolated fish oil had lower concentrations to begin with, or the oil in the capsule had oxidized and degraded over time. . EPA and DHA are prone to oxidation and break down to form a soup of peroxides, aldehydes and ketones. In fact, fish oil supplement manufacturers usually add antioxidants to their capsules to slow this process down.
Quality control
When the New Zealand team tested the oxidation values of the fish oil capsules, 92% exceeded one or more international recommendations. But older capsules that had been on the shelves for longer showed no difference in oxidation values compared to newer ones. This suggests that there were lower levels of active EPA and DHA early in the manufacturing process, and that many companies may not be testing their individual batches of fish oil.
What can such oxidation values mean for the consumer? Whereas some studies indicate that oxidative degradation products may in fact be responsible for the anti-inflammatory benefits of fish oil, at high experimental doses they may cause organic toxicity, growth retardation and accelerated atherosclerosis. The overall health effect – if any – of consuming high oxidation value products is still unclear. Since there is no formal evaluation of their health effects, the levels of oxidation in fish oil capsules are subject to recommendations based on appetite rather than on legal requirements based on security.
If this research is representative of the global market, consumers have a 1 in 10 chance of buying fish oil capsules that contain the promised levels of EPA and DHA. These ratings could improve a bit if they stick to the premium brands. Until better standards and regulations hit the fish oil supplement market, it’s probably a good idea to look for your brain elsewhere.