(and when food isn't enough)

A spoonful of fish oil is not a magic shield against inflammation, heart disease or cancer. But omega-3 fats do have important jobs in your body, and knowing what they can and can’t do makes it much easier to decide whether a supplement belongs in your routine.

My starting point is always food. Living in Portugal, I wait for sardine season, so fresh sardines are not on my own table in November. If you’re in the Netherlands, you’re luckier: maatjesharing is often still available now. Not the new-season “Hollandse Nieuwe”, but herring from the summer catch, preserved and available later in the year. A lovely reminder that nourishing food can be both practical and a pleasure.

ALA, EPA and DHA

“Omega-3” is a family name, not a single fat.

• ALA is found in plant foods such as flaxseed, chia, walnuts and rapeseed oil.
• EPA and DHA are long-chain omega-3 fats found mainly in oily fish and seafood.

Your body can convert some ALA into EPA and DHA, but the conversion is limited and varies between people. So flaxseed and walnuts are nutritious additions, but they don’t reliably provide the same amount of EPA and DHA as oily fish.

EPA and DHA become part of cell membranes. The flexible outer layer around your cells. Think of a membrane as a busy border crossing: it helps regulate what enters and leaves, and how cells receive messages. DHA is especially abundant in the brain and retina. That makes omega-3 relevant to cell and brain biology, but it does not mean that taking a supplement has been proven to prevent memory loss or treat disease.

Inflammation: the off-switch

You may have heard that omega-3s are “anti-inflammatory”. That word is too neat for what actually happens. Inflammation is part of your body’s normal defence and repair system, and the interesting part is not blocking it. The interesting part is whether your body can bring that response back down again once the job is done.

EPA and DHA are the building blocks for molecules called specialised pro-resolving mediators, including resolvins and protectins. They do not switch your immune system off. They coordinate the resolution phase, like a clean-up crew arriving after the emergency response. That is a different job from “fighting inflammation”, and it is exactly why the balance with omega-6 matters so much. Because the clean-up crew can only do its work if there is enough material to build it from.

The omega-6 ratio

I am the first to raise an eyebrow at stories that turn a single nutrient into the villain. But with omega-6, the picture deserves a closer look than the usual “it’s all fine, don’t worry” line. First the basics, kept really simple.

Omega-3 and omega-6 are both essential fats. Essential here means: your body cannot make them, so you must get them from food. So far, no problem. The real difference lies in what they do next:

• Omega-3 (EPA and DHA, mainly from oily fish) are the building blocks of signalling molecules that calm inflammation down and clean it up. Think of them as the brake.
• Omega-6 (linoleic acid, mainly from sunflower, corn and soybean oil) convert in your body into arachidonic acid, the building block of signalling molecules that drive inflammation, like prostaglandins and leukotrienes. Think of that as the accelerator.

Both have a job: your body needs the brake and the accelerator. The problem is that we now press the accelerator all day long. Our ancestors ate omega-6 and omega-3 at roughly 1:1. Today’s ratio is not the often-quoted 15:1; real-world estimates run from 1:40 to well above 1:60, mainly because sunflower, corn and soybean oils hide in almost every processed product.

And that is where it goes wrong. The more lopsided the ratio, the harder your body is pushed towards inflammation. Research shows such an imbalance can genuinely feed low-grade chronic inflammation. (Simopoulos, 2002; 2016) Is it the only factor? No, stress, sleep, smoking and movement count too. But it is a dial you can actually turn yourself.

A favourable balance sits around 1:2. You will not get there from supermarket food built on processed products, but you can get close: put oily fish on your plate more often and cut back on sunflower, corn and soybean oil. No need to fear a splash of olive oil or a handful of nuts; the problem sits in the daily processed base, not in one natural product.

For more on the different fatty acids, you can read my guide to omega-3, omega-6 and omega-9. And for a wider look at how inflammation fits into the heart-health discussion, see The Great Cholesterol Debate.

Brain, heart, gut

For the brain, DHA has an important structural role. A 2023 review discusses how omega-3s may relate to cognitive function, but the evidence is not a promise that a supplement will prevent cognitive decline. Eating fish as part of a balanced pattern is different from treating a supplement as a brain-health guarantee. (Welty, 2023)

For the heart, omega-3s can lower triglycerides at sufficiently high doses. Some cardiovascular trials have also found benefits from specific prescription products in selected higher-risk patients. But those findings don’t mean that every fish-oil capsule reduces heart attacks. The product, dose and person matter; the 2020 review by Watanabe and Tatsuno is a useful overview of the evidence. (Watanabe & Tatsuno, 2020)

And your gut? There’s early research into how omega-3s may influence gut bacteria and their activity. It’s interesting, but not yet a reason to buy a supplement for a promised “microbiome reset.” (Costantini et al., 2017)

Start with food

The official guidelines recommend roughly 100 grams of fish per week, preferably oily fish. Once a week is simply not enough. My own standard: oily fish at least twice a week, plus one to two generous tablespoons of ground flaxseed or chia seed daily for the ALA side. That is how you build your EPA and DHA, and the balance with omega-6, at the same time.

Size matters here too. Small fish such as sardines, herring and mackerel sit lower in the food chain, so they accumulate fewer heavy metals and other toxins than large predators like tuna or swordfish. Good for your omega-3 intake, kinder to your toxic load.

Fresh sardines aren’t always on the menu in November, and that’s okay. Try maatjesharing, tinned sardines or another oily fish you enjoy. The best plan is one you’ll actually look forward to eating. For a deeper look at my own sardine ritual, read (in Dutch) Sardientjes in de Algarve: de lekkerste (en diepste) metabole reset die er is.

If you rarely eat fish, don’t eat it at all, or have a reason to check your omega-3 intake more closely, a supplement may be worth discussing. But it’s a question of fit, not an automatic next step.

Look beyond the label

“1,000 mg fish oil” does not tell you how much EPA and DHA you’re getting. Check the label for the actual EPA and DHA amounts per daily serving.

How to spot good quality, step by step. Fish oil is just that, an oil, and oil goes rancid when it sits around with air, light and heat. Exactly like olive oil or a carton of milk. Oxidised fish oil smells or tastes like old paint or stale fish; with capsules you sometimes only notice it when you bite one open. Rancid oil is not just unpleasant, your body can do less and less with it. Here is what to actually check:

• Read EPA and DHA per daily serving, not the “1,000 mg fish oil” on the front. Fish oil without EPA and DHA is like coffee without caffeine: it says so on the label, but it does little.
• Check the form. Triglyceride form is generally absorbed somewhat better than ethyl ester. On an ethyl ester product, always take it with a meal containing fat.
• Buy small and check the best-before date. Fish oil degrades faster than you think. A year’s supply looks like a bargain, but in the final months you are swallowing declining quality. The fresher you buy, the better.
• Choose softgels or a dark bottle. A softgel is a soft gelatine capsule with liquid oil inside. Each softgel is individually sealed, so the oil barely touches air until you swallow it. Liquid oil in a bottle starts oxidising the moment you open the cap.
• Store cool, dark and closed. After opening: preferably in the fridge and finish within a few weeks. Above the radiator or in sunlight is the worst place you can pick.
• Trust your nose and tongue. If the oil smells or tastes rancid, it is oxidised and past its prime. With softgels you can occasionally bite one open to check. Fresh-fatty is good; old paint means bin it.
• Check whether the brand publishes its numbers. Serious brands publish per-batch test results: how much EPA and DHA is really inside, the TOTOX value (a rancidity meter: the lower, the fresher) and contaminants like heavy metals. Buying online? Look for those batch reports or independent certifications on the product page. No numbers anywhere? That silence is an answer in itself.

Liquid or softgels? Liquid is not automatically better, it is mainly more fragile. Dose, freshness and consistency matter more than the packaging.

DoNotAge Pure Omega-3

If you’ve checked your diet and feel a supplement makes sense, DoNotAge Pure Omega 3 is one option. It is not a hard capsule with powder but a softgel: a soft gelatine capsule with liquid oil inside, each one individually sealed, so the oil only meets air when you swallow it. The product label lists 800 mg EPA and 600 mg DHA in its two-softgel daily serving, in the better-absorbed triglyceride form. The brand publishes batch test results, so you can check freshness (TOTOX) and purity yourself; see the product page for current details.

That’s a supplement option, not a substitute for fish, medical care or an individual assessment. High-dose omega-3 can be appropriate in some medical situations, but triglyceride treatment doses are not the same as a general wellness dose. Higher doses have also been associated with a greater risk of atrial fibrillation in some studies.

Please check with your doctor or pharmacist before starting omega-3 if you take blood-thinning medication, have a bleeding disorder or a history of atrial fibrillation, or are preparing for surgery. If you’re receiving cancer treatment, ask your oncology team too, especially if your treatment affects your blood counts, clotting or planned procedures.

Three simple questions

Ask yourself three questions:

1. Do I eat oily fish about twice a week?
2. If not, could I add a fish I enjoy, or would a supplement be more realistic?
3. Have I checked the EPA and DHA dose, product quality and any medication considerations?

If the answer to the first question is yes and there’s no specific medical reason to supplement, food may be enough. If fish is rarely on your plate, a well-chosen supplement may be a practical alternative to discuss with a health professional.

And if you’d like to explore the DoNotAge option, there’s a Black Friday sale running through November 30, with offers of up to 40% off and an extra 10% with code DrNaomi. The extra code is not valid on Routine subscriptions; check the offer details before ordering. See the omega-3 option and current offers here.

I’m all for using helpful tools, but first, let’s make sure we understand what the tool is for. Sometimes that means a supplement. Sometimes it means putting maatjesharing on the table and enjoying every bite. 🐟