Photo by Pavel Kalenik on Unsplash
In short: Omega-3s are healthy fats your body cannot make in sufficient amounts, so they have to come from food. Two of them, EPA and DHA, are built into the walls of your brain cells and help those cells talk to each other. You find them mainly in oily fish, and a plant form in walnuts, flaxseeds, chia seeds and rapeseed oil. They support normal brain function all through life, but they are not a cure for depression or dementia.
You walk into the kitchen and stop. What did you come in for? Later, you read the same paragraph three times, and in the afternoon your head feels as if it were wrapped in cotton wool. On days like these, we blame age, tiredness or too much to think about. We rarely think of what is on our plate.
Yet your brain is an organ like any other, and it is built from what you eat. A large part of it is fat. So the kind of fat you give it matters, and omega-3s are among the ones it values most.
What are essential omega-3 fatty acids?
Omega-3 fatty acids are polyunsaturated fats found in food. Like all fats, they give your body energy, and they also have many roles in your heart, blood vessels, lungs, immune system and hormone system. They are called essential because your body cannot produce them on its own in the amounts it needs.
There are three main types:
Alpha-linolenic acid (ALA) is the plant form. It is found mostly in seeds such as flaxseeds, chia and hemp, in walnuts, in some vegetable oils such as rapeseed (also called canola) and soybean, and in small amounts in green vegetables such as Brussels sprouts, spinach and kale. The body converts ALA into EPA and DHA, but only a small fraction of it.
Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are found mostly in oily fish, such as mackerel and salmon.
You may also have heard of omega-6 fats, such as linoleic acid, which is in sunflower oil, pine nuts, pecans and sunflower seeds. They are essential too, but most of us already eat plenty of them, because they are in so many oils and ready-made foods. Omega-3s are the ones that tend to be missing.
What role do omega-3s play in the brain?
EPA and DHA matter for normal brain function and development at every stage of life. They are abundant in the membranes of brain cells. You can picture the membrane as the skin of the cell: when it is supple and in good condition, messages pass easily from one cell to the next. Omega-3s help keep it that way.
This is why they are so important during pregnancy and the first years of life, when a child’s brain is being built. And why they remain useful later, when we want to stay clear-headed and keep learning.
DHA is also very important for your vision: the retina, at the back of the eye, contains a great deal of it.
Omega-3s also help keep your blood vessels in good condition, and your brain depends on a steady supply of oxygen and nutrients through those vessels. What is good for your heart is, very often, good for your head.
Can omega-3s prevent or cure mental disorders?
There has been a great deal of interest in what omega-3s might do for conditions such as depression and dementia, and you’ll see confident promises on many packets. It’s best to be careful here.
Omega-3s, DHA in particular, are part of what a healthy brain is made of, and people who eat fish regularly tend to do well as they age. But omega-3s have not been proven to prevent or cure dementia, such as Alzheimer’s disease. Dementia has many causes, and our understanding of the brain is still incomplete.
For low mood and depression, the findings are more encouraging, although they vary from one person and one product to another. It is a possible support to discuss with your doctor. It is not a treatment to try on your own, and it never replaces the care you may need.
So think of omega-3s as one of the things that feed your brain well, alongside sleep, movement, daylight, and people you love. Your brain also listens closely to your digestion, as I explain in how your gut and brain communicate.
Which foods are good sources of omega-3?
Omega-3s are found naturally in some foods and are added to some fortified foods. You can get them by eating a variety of the following.
Oily fish, for EPA and DHA
Sardines, mackerel, herring, anchovies, salmon and trout. The small ones are often the least expensive, and tinned sardines or mackerel are perfectly good: keep a few tins in the cupboard and you always have a quick lunch.
Seeds, nuts and oils, for ALA
Walnuts, flaxseeds, chia seeds and hemp seeds, and rapeseed, walnut and flaxseed oils. Flaxseeds are best ground, otherwise they pass straight through you. The delicate oils, walnut and flaxseed, are for dressings and for drizzling over a finished dish, not for the frying pan, and they keep best in the fridge.
Seaweed and algae
Fish get their omega-3s from the algae they eat. Some seaweeds contain a little EPA and DHA, and oils made from algae exist for people who don’t eat fish.
What if you don’t eat fish?
If you eat vegetarian or vegan, give the plant sources a regular place: walnuts on your porridge, ground flaxseeds in your yoghurt, rapeseed oil in your dressing. Because the body converts only a small part of ALA into EPA and DHA, it is worth asking your doctor or pharmacist whether you need anything in addition. You’ll find more on this in how to meet your nutritional needs on a plant-based diet.
Try this: omega-3 in an ordinary week
Breakfast: a spoonful of ground flaxseeds or chia seeds stirred into your porridge or overnight oats, with a few walnuts on top.
Lunch: sardines or mackerel on wholegrain toast with lemon and a tomato salad, once or twice a week.
Dinner: a piece of salmon or trout baked in the oven with vegetables. It takes fifteen minutes and almost no washing up.
Salads: make your dressing with rapeseed or walnut oil for a change from olive oil.
Snack: a small handful of walnuts with an apple at four o’clock, when your concentration dips.
A plate like this does more than deliver omega-3. It brings colour, fibre and protein with it, which is why food works so well as a whole. If you’d like to go further, read why eating a rainbow matters and how to boost your mental energy.
What about supplements?
Fish oil and algae oil supplements exist, and they differ a lot from one another. Whether one makes sense for you depends on what you eat, on your health and on any medication you take. They are not suitable for everyone. Please ask your doctor or pharmacist before you buy one.
Remember that a food-based approach to getting enough omega-3 fatty acids is always recommended.
Frequently asked questions
Which foods are richest in omega-3?
Oily fish such as sardines, mackerel, herring, anchovies, salmon and trout are the main source of the two forms your brain uses most, EPA and DHA. Walnuts, ground flaxseeds, chia seeds, hemp seeds and rapeseed oil provide the plant form, ALA.
Can I get enough omega-3 if I do not eat fish?
Plant foods give you ALA, and your body turns only a small part of it into EPA and DHA. Eat walnuts, flaxseeds, chia or rapeseed oil every day, and ask your doctor or pharmacist whether you need anything more, for example an oil made from algae.
Does omega-3 improve memory or prevent dementia?
Omega-3s are part of the structure of your brain cells and support normal brain function at every age. They have not been shown to prevent or cure dementia, which has many causes. Eating fish, nuts and seeds regularly is one helpful habit among others, alongside movement, sleep and staying connected to people.
Should I take a fish oil supplement?
A food-based approach always comes first. Whether a supplement makes sense for you depends on your diet, your health and any medication you take, and omega-3 supplements are not suitable for everyone. Ask your doctor or pharmacist before you start.
When should I talk to my doctor?
If you feel low, anxious or forgetful in a way that worries you or lasts, please see your doctor: food can support you, but it does not replace care. Also ask before taking omega-3 supplements if you are pregnant, take blood-thinning or other medication, or have surgery planned.
Would you like some help?
Getting enough healthy fats onto your plate, in meals you enjoy and can afford, is one of the things we work on in my group programmes in nutrition and health, such as Six Tuesdays in Montignac. If you’d like to hear when the next group opens, write to me at hello@catherinepolet.coach.
Would you rather work one to one? I also coach online. Book a free 20-minute call, and we’ll look at what you eat in a normal week and where a little more food for your brain could find its place.
About Catherine
I’m Catherine Polet, a holistic nutrition health coach, yoga and autogenic training teacher for more than 30 years, author and speaker. I help people find a way of eating and living that suits their own body, online in English, French, Spanish and German, and in person in Southwest France.
