Omega-3
EPA · DHA
An essential fat that the body needs but cannot make, with an enormous reputation — almost a cure-all. This guide tells the honest story: it works well for a few things, so-so for others, and for several of its claimed benefits there is no evidence to support them.
The essential fat that begins in algae
What is omega-3?
Omega-3 is a type of fat. One of the good ones — the kind the body needs and cannot make on its own. But several different fats share that name, and they should not be lumped together. The two that really matter for health are and , which come from the sea — oily fish, shellfish, algae. There is a third, , of plant origin (flax, chia, walnuts), but the body converts it into EPA and DHA with enormous difficulty: only a small fraction ever gets converted. That is why, when we talk about omega-3 with an effect, we are talking mostly about EPA and DHA.
Omega-3, omega-6 and omega-9 are not the same thing, and it is not all the same which one you take. The one usually in short supply in today’s diet is the 3. The others rarely fall short.
What is it for?
Omega-3 carries an enormous reputation. The reality, with the data available today, is that it works well for a few things, so-so for others, and for several of its attributed benefits there is no evidence to support them.
Where the evidence is firmest is in lowering triglycerides: at sufficient doses — considerably higher than those of a maintenance capsule — omega-3 reduces them clearly. It is worth separating this from the most widespread belief, that “omega-3 protects the heart”. At usual supplement doses, the large modern trials have not found that it prevents heart attacks or strokes in the general population. It is one of the most striking gaps between the reputation and the numbers.
In inflammation and joints there is a consistent signal: in rheumatoid arthritis, omega-3 helps reduce the need for anti-inflammatories. In mood, as support for a treatment — not on its own — and with EPA-rich formulas, the effect captured by the studies exists, though it is modest. And in pregnancy, providing DHA is a well-established recommendation of the food safety agencies (around 200 mg a day), with benefit above all in women who start from low levels.
In sport, what is best supported is a modest aid in recovery and muscle soreness after intense efforts. What does not appear in the studies is that it increases muscle mass or performance. The headline “omega-3 to perform better” does not hold up.
In memory and prevention of cognitive decline, the evidence is weak or nil: in already-established dementia it has shown no benefit. Of everything attributed to it, this is the least supported.
Who is it for?
It makes more sense to consider omega-3 if you eat little oily fish, if you have high triglycerides, during pregnancy (for the DHA), or if you live with an inflammatory disease such as rheumatoid arthritis. For someone who already eats oily fish two or three times a week, the first “source” should be the plate, not the bottle.
Dose
Doses change depending on what for. For general maintenance, what a couple of servings of oily fish a week provide is usually enough. To lower triglycerides, considerably higher doses are needed, and that is already the territory of medical supervision. Take it with a meal that has some fat in it, because it improves its absorption quite a bit.
When you read the label, look at the milligrams of EPA and DHA, not those of “fish oil” in total. A “1,000 mg” bottle may have only 300 mg of what really matters.
And, contrary to what instinct suggests, more is not better: at very high doses risks appear, as we will see at the end.
Absorption and bioavailability
Are all forms the same?
Not entirely. Fish oil is the classic form. Algae oil is the option for vegans or for those allergic to fish, and it provides the same EPA and DHA: it is not a second-rate version. tends to sit better with those who get fishy reflux. And plant ALA (flax, chia) does provide omega-3, yes, but the body makes poor use of it to produce EPA and DHA, so it does not replace the previous ones.
Quality seals
Omega-3 is a delicate product: it oxidizes (goes rancid) easily, and coming from the sea it can carry contaminants. That is why it is worth looking at independent quality seals. In Europe the most relevant is IFOS, which analyzes the product batch by batch.
Scientific evidence
Myths
That “seed oils (omega-6) are inflammatory”: it is a debated and probably exaggerated matter; the problem with the modern diet is not so much the excess of 6 as the lack of 3. And that “it helps you lose weight”: its effect on weight is, in practice, irrelevant.
What science still isn’t sure about
Who should not take it?
Here we must speak with honesty and caution, because each person’s health is at stake.
In pregnancy, DHA is advisable, but one should watch out for cod liver oil: its excess of vitamin A can harm the fetus. Better a standardized fish or algae oil.
At high doses, omega-3 is associated with a higher risk of atrial fibrillation (a heart arrhythmia). It is the main reason why “more” does not mean “better”.
And, as with any supplement, this information does not replace the advice of a healthcare professional.