What it is
Fat molecules have a long backbone of carbon atoms bound to hydrogen atoms. When a particular carbon is “saturated,” it forms a single bond with two other carbon atoms, and two hydrogen atoms. When consecutive carbons are “unsaturated,” they’re each only bound to a single hydrogen atom, allowing the neighboring carbon atoms to form a double bond with each other. This typically causes a bend in the carbon backbone.
Eicosapentaenoic acid (EPA) is a polyunsaturated fat with five pairs of unsaturated carbons, and multiple bends in its carbon backbone. These bends in the carbon backbone make the fat molecules less likely to stack up in an orderly fashion, thus making EPA a liquid at room temperature.
EPA is an essential fatty acid.
What it does
EPA and DHA are the two most important omega-3 fats. They’re incorporated into cell membranes, and influence inflammation (reducing inflammation and platelet aggregation). So, the number of specific effects potentially attributable to EPA and DHA would be too long to list, but most of those effects would be downstream of the effects of EPA and DHA on inflammation. Very high intakes of EPA may also lower triglyceride levels.
Recommended intake
The recommended combined intake of EPA and DHA is 250mg/day. Higher doses of EPA (generally 2-4g/day) are required for the effect on triglycerides.
Likelihood of tracking completeness: Very low
EPA is not a nutrient food manufacturers are required to disclose on nutrition labels. The vast majority of food manufacturers do not voluntarily list EPA content on nutrition labels, so most branded products in the MacroFactor database lack information on EPA. So, if you’d like to accurately track your EPA intake, you’ll need to make a point of mostly tracking “common foods,” which come from research-grade databases that have full nutrient reporting.
For more on when you can track using branded foods versus common foods when you’re trying to accurately monitor your intake of particular nutrients, you should check out this article.
Likelihood of insufficient intake: Very high
Most adults in developed countries consume less than the recommended amount of combined EPA and DHA. For example, adults in the US have an average intake of about 100mg/day.
For more on nutrients with a greater likelihood of insufficient or excessive intake, you should check out this article.
Signs of deficiency/insufficiency
The earliest signs of insufficient EPA and DHA intake are dermatitis and rough, scaly patches of skin. Severe EPA and DHA deficiencies can lead to poor vision due to retina damage, reduced immune function, mood disturbances, and impaired cognition.
Good sources
Coldwater sea animals generally have the highest levels of EPA and DHA. Caviar (and other fish eggs) and seal fat are actually at the top of the list with more than 2g of combined EPA and DHA per 100 calories. Cod liver oil is a classic EPA and DHA powerhouse as well. But, in terms of more readily accessible foods, salmon, mackerel, shad, sardines, anchovies, herring, pacific oysters, and fatty tuna are particularly high in EPA and DHA, with 0.8-1.3g of combined EPA and DHA per 100 calories.
For vegan sources of EPA and DHA, various algae are really your only option, since plants don’t synthesize EPA or DHA. Dried seaweed (nori) is a decent source of EPA and DHA, but taking an algae oil supplement is your best bet. Many plants are rich in ALA, which can be converted to EPA and DHA, but since the conversion of ALA to EPA and DHA is so inefficient, you shouldn’t rely on ALA intake to meet your EPA and DHA needs.
Learn more
If you’d like to learn more about micronutrients generally, there’s a five-part series on the MacroFactor website you might enjoy.