Omega-3: What It Does, Where to Find It and How to Add It to Your Diet

Omega-3 fatty acids are among the most talked-about nutrients in healthy eating, and for good reason: the body needs them but cannot make enough on its own, so they have to come from food. This article explains what they are, what they do, where to find them and how to get enough without overdoing it.

What omega-3s are

There are three main types. ALA (alpha-linolenic acid) is found mostly in plant foods such as flaxseed, chia seeds and walnuts. EPA and DHA are found mainly in oily fish and in some microalgae. The body can convert a small share of ALA into EPA and DHA, but the conversion is limited, so getting EPA and DHA directly is usually more effective.

What they do

Omega-3s are part of cell membranes and take part in many processes in the body. The best-studied roles include:

• Heart: regular intake of EPA and DHA is linked to normal heart function. European authorities recognise this effect for an intake of around 250 mg of EPA and DHA per day.
• Brain and eyesight: DHA is an important component of brain tissue and the retina, and it contributes to maintaining their normal function.
• Pregnancy and early childhood: DHA plays a part in the development of a baby's brain and eyes, which is why it is often recommended at this stage, always under medical guidance.
• Triglycerides: high doses, usually prescribed or recommended by a professional, can help lower blood triglycerides.

It is worth keeping expectations realistic: omega-3s are one part of a healthy eating pattern and do not replace exercise, good sleep or medical treatment.

Best food sources

For EPA and DHA, the best choices are oily fish such as sardines, mackerel, salmon, herring and anchovies. For ALA, you can rely on:

• ground flaxseed (about one tablespoon a day);
• chia seeds, which work well in yoghurt, porridge and desserts;
• walnuts, a small handful as a snack;
• rapeseed or flaxseed oil, used cold on salads.

Flaxseed should be ground, otherwise it passes through the gut without being properly absorbed. Keep it in the fridge so it does not go rancid.

How much to eat

The most common advice for healthy adults is to eat fish twice a week, with at least one portion of oily fish. A portion is roughly 120 to 150 grams of cooked fish. If you do not eat fish, rely on plant sources of ALA every day and, if needed, on algae-based supplements, which provide DHA and sometimes EPA.

Supplements: when they make sense

A fish oil or algae supplement can be useful for people who rarely eat fish, for vegetarians and vegans, and at specific life stages. Before you start, keep in mind:

• check the label for the amount of EPA and DHA, not just the amount of oil per capsule;
• very high doses may raise the risk of bleeding, especially in people taking blood thinners;
• anyone with a fish or shellfish allergy should check where the product comes from;
• pregnancy, breastfeeding, chronic conditions and medication call for a conversation with a doctor or pharmacist first.

Easy ways to add omega-3 to your routine

Small changes help: swap one meat meal for grilled sardines, stir a spoonful of chia into your breakfast yoghurt, add walnuts to a salad, or serve tinned mackerel with vegetables. Choose grilled, steamed or baked fish rather than fried, which adds less healthy fat.

In short

Omega-3s are essential nutrients that must come from food. Oily fish twice a week, seeds and nuts day to day and, when needed, a well-chosen supplement are the simplest way to get enough. This article is for information only and does not replace advice from a health professional.