What is omega-3 EPA and DHA?

The family, named for a bond, and the parent, ALA, with its poor conversion

What omega-3, EPA and DHA are is a family tree, and the family is named for a bond. Omega-3 fatty acids are polyunsaturated fats, long chains of carbon with several double bonds, and the name records where the first double bond sits counting from the tail end of the chain, the omega end, three carbons in, which is a structural fact that makes the family behave differently from the omega-6 family, whose first bond sits six carbons in, and from the saturated fats with no double bonds at all, the double bonds putting kinks in the chain that keep membranes fluid and giving oxygen the sites it attacks when an oil goes rancid. The parent of the family is ALA, alpha-linolenic acid, eighteen carbons and three double bonds, the omega-3 of plants, found in flax and chia seeds, walnuts, rapeseed oil and hemp, and the omega-3 a food label usually means when it says a plant food is a source of omega-3. The body can lengthen and desaturate ALA into the marine forms, but poorly: the conversion literature finds ALA converted to EPA at a few percent in most adults, higher in women of childbearing age and lower on a high omega-6 diet, and to DHA at well under one percent, so a tablespoon of flax delivers a lot of ALA and a few milligrams of EPA and almost no DHA, and a diet with plenty of plant omega-3 and no fish or algae does not reliably build EPA and DHA in the body, the vegan omega-3 page's reason for algal oil.

The children, EPA and DHA, what each does, the sentences that hang on them, and the label line that counts

The children are EPA and DHA, and they come ready-made. EPA, eicosapentaenoic acid, is twenty carbons with five double bonds, and DHA, docosahexaenoic acid, is twenty-two with six, the longest and most unsaturated fatty acids in the diet, made by marine algae and concentrated up the food chain into the oily fish, anchovy, sardine, mackerel, herring and salmon, whose body oil is what a fish oil softgel contains, and available directly from algae in an algal oil for a vegan. What each does is different: EPA is the precursor of the resolving mediators the inflammation literature studies and the omega-3 the mood research favoured, and DHA is the structural fatty acid of brain and retina membranes, the most abundant omega-3 in the brain and the one the maternal claim concerns, which is why a standard fish oil's 3 to 2 EPA to DHA ratio serves the combined claims and a DHA-heavy oil serves the DHA ones, the ratio page's read. The register's sentences hang on the children and not the parent: EPA and DHA contribute to the maintenance of normal heart function at 250mg a day combined, DHA contributes to the maintenance of normal brain function and normal vision at 250mg of DHA a day, and EPA and DHA contribute to normal triglycerides and blood pressure at two and three grams, while ALA holds one sentence of its own, a contribution to the maintenance of normal blood cholesterol levels at two grams a day, a plant claim that does not reach the marine ones. The label line that counts follows: a tub's omega-3 total or fish oil weight includes the oil's other fats and, on a plant product, ALA, so the number a reader reads is the EPA and DHA line, 180 and 120 in a standard 1000mg softgel, the 300mg that reaches the heart claim in one and the DHA claims in two or three, with a product that gives only an omega-3 total having hidden the children in the family. The tree filed: omega-3 a family named for a bond, ALA the plant parent with a few percent conversion, EPA and DHA the marine children with the sentences, and the label's EPA and DHA line the number, with the worked example naming and counting both children, 180mg EPA and 120mg DHA, £14.99 for 90 at 17p.

The verdict, a family named for a bond, a parent that barely converts, and two children who hold the sentences

What is omega-3, EPA and DHA: omega-3 is a family of polyunsaturated fatty acids named for the first double bond sitting three carbons from the tail, ALA is the plant parent from flax, chia, walnuts and rapeseed that the body converts to EPA at a few percent and to DHA at well under one percent, and EPA and DHA are the marine children, twenty and twenty-two carbons with five and six double bonds, made by algae and concentrated in oily fish, the forms the body uses, EPA feeding the resolving mediators and DHA building brain and retina membranes, and the forms the register's sentences hang on, heart at 250mg combined and brain and vision at 250mg of DHA, so that the number on a label is the EPA and DHA line and not the omega-3 total. The two children named and counted: Futuro Labs Omega 3 Fish Oil, 1000mg fish oil providing 180mg EPA and 120mg DHA, 90 for £14.99 at 17p a day.

What to check on the label

Questions people also ask

What is the difference between omega-3, EPA and DHA?

Omega-3 is the family, polyunsaturated fats named for a double bond three carbons from the tail; EPA and DHA are two members, the long marine forms from oily fish and algae that the body uses and the register's sentences hang on, while ALA is the shorter plant member from flax and walnuts.

Does the body make EPA and DHA from plant omega-3?

Barely: ALA from flax, chia, walnuts and rapeseed is converted to EPA at a few percent in most adults and to DHA at well under one percent, so a plant-rich diet with no fish or algae does not reliably build EPA and DHA, which is why a vegan takes an algal oil.

What does EPA do versus DHA?

EPA is the precursor of the resolving mediators the inflammation literature studies and the omega-3 the mood research favoured, while DHA is the structural fatty acid of brain and retina membranes, the most abundant omega-3 in the brain and the one the brain, vision and maternal claims concern.

Which number should I read on an omega-3 label?

The EPA and DHA line, 180 and 120 in a standard 1000mg softgel, since the omega-3 total includes other fats and, on plant products, ALA, and the fish oil weight is the carrier rather than the actives; a product giving only an omega-3 total has hidden the two that matter.

Where do EPA and DHA come from?

Marine algae make them and oily fish concentrate them up the food chain, anchovy, sardine, mackerel, herring and salmon supplying the body oil in a fish oil softgel, with algal oil supplying DHA, and sometimes EPA, directly for a vegan.

Sources

1. The alpha-linolenic acid conversion literature: the plant omega-3 ALA from flax, chia, walnuts and rapeseed is converted to EPA at a few percent and to DHA at well under one percent in most adults, higher in women of childbearing age and lower on a high omega-6 diet, so plant sources do not reliably supply EPA and DHA. PubMed record
2. EFSA Panel on Dietetic Products. Scientific opinion on the substantiation of health claims related to EPA and DHA and normal function of the heart (250mg daily condition of use). EFSA Journal 2010;8(10):1796. https://www.efsa.europa.eu/en/efsajournal/pub/1796
3. EFSA Panel on Dietetic Products. Scientific opinion on health claims related to DHA: maintenance of normal brain function and normal vision (250mg DHA daily condition of use). EFSA Journal 2010;8(10):1734. https://www.efsa.europa.eu/en/efsajournal/pub/1734
4. Review evidence on n-3 docosapentaenoic acid (DPA): the intermediate long-chain omega-3 between EPA and DHA, present in fish and blood, with early-stage research and no authorised claims. PubMed record

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