Humans are currently getting fish oil from the tissues of oily fish such as sardines, salmon, and tuna. However, the fish itself does not produce the famous omega-3 fatty acids contained in the oil, but they rather accumulate them by consuming microalgae, the original holder of EPA and DHA (too bad we cannot synthesize it by ourselves!). Together with a high quantity of antioxidants, these compounds prevent the oxidative degradation of lipids that results in cell damage. Thus, omega-3 fatty acids are thought to be important for normal cellular metabolism.
Predictably, the health effects of fish oil supplementation seem to be broad and diverse: cardiovascular health, hypertension, inflammation, developmental disorders, mental health and even cancer – with poor evidence, but the results of the clinical trials are not conclusive. While the animal evidence available in regard to cognitive functioning is rather uniform (for example, it seems that fish oil significantly attenuates reactivity to mental stress in dogs, cats, and mice), the one directed to healthy humans is still controversial.
There are certainly studies that advocate for its efficacy, from schoolchildren showing improvement in cognitive function after consuming a bread spread containing fish flour, to subjects with mild cognitive impairment who showed improvement in their memory function. However, the actual last studies challenge these results, arguing that potential target populations who would more likely benefit from omega-3 fatty acids would be just Alzheimer’s disease patients.
As with any current brain supplement, ideally, further research has to be done until reaching consensus. Nevertheless, it should be said that fish oil supplementation does not pose a safety concern for adults. And as any nootropics user have probably realized, the fact that we, as a scientific community, do not understand how something works (yet) does not mean that it doesn’t work at all.