Ask a biochemist and they'll tell you omega 3 is a polyunsaturated fatty acid – a type of fat with a distinctive chemical structure involving double molecular bonds. The name "omega 3" refers to the position of the last of these double bonds, three carbon atoms from the tail of the molecular chain. Ask a nutritionist, and they'll tell you omega 3 is an "essential" fatty acid, meaning the body can't produce it itself – it has to come from diet.
Why You Need Omega 3 in Your Diet
The body relies on a complex balance of compounds to fuel the chemical processes that keep it functioning. Omega 3 plays a role in several fundamental physical functions, including:
- Generating energy
- Creating hormones that regulate inflammation, blood clotting and arterial function
- Supporting healthy immune, heart and lung function
- Regulating circulating fat levels
- Supporting joint flexibility and comfort
- Building cell membranes and supporting nerve connections
- Promoting cardiovascular health
Low omega 3 intake over a prolonged period has been associated in research with a range of health concerns, including:
- Attention deficit hyperactivity disorder (ADHD)
- Heart disease
- Asthma
- Eczema
- Stroke risk
- Arthritis
- Cognitive decline in later life
These are associations identified in research, not confirmed direct causes, and exactly how much omega 3 is optimal for health remains an area of ongoing debate among nutritionists.
Is Omega 3 Found in All Fish?
There are three forms of omega 3: alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish is the principal source of the latter two. Oily fish in particular are rich in omega 3, including:
- Herring
- Salmon
- Mackerel
- Tuna
- Anchovies
- Sardines
- Trout
Cod liver oil, a traditional supplement made from cod liver, can be added to this list too. All of these are also rich in other vitamins and minerals, which is why doctors generally recommend eating oily fish at least twice a week.
What Other Foods Contain Omega 3?
If fish isn't for you – whether by preference or as part of a vegan lifestyle – there are still good options:
Green leafy vegetables
Alongside their other health benefits, many green leafy vegetables contain a useful level of omega 3, including spinach, sprouts, cauliflower and broccoli.
Walnuts
Walnuts are notably high in omega 3 – over two grams per ounce – alongside healthy fibre, copper, manganese and vitamin E.
Flax Seeds
Flax seeds are so rich in omega 3 that flaxseed oil is widely used as a dietary supplement, with over seven grams of omega 3 in every tablespoon.
Pumpkin Seeds
Another good source of omega 3, alongside calcium, beta-carotene, magnesium, iron, zinc, folate (vitamin B9) and omega 6.
Soya
A familiar supermarket staple, particularly for vegetarians and vegans. Half a cup of soya provides a generous six to seven grams of omega 3, alongside magnesium, potassium, and vitamins B2, K and folate.
Meat From Grass-Fed Animals
Another fish-free omega 3 source, though not suitable for vegetarians. The omega 3 found in plant sources is alpha-linolenic acid (ALA), distinct from the longer-chain EPA and DHA found in fish. The body can convert ALA into EPA and then DHA, but this conversion process is inefficient and depends on a careful nutrient balance – consuming EPA and DHA directly from fish is a more efficient way to benefit from omega 3. Excess omega 6 intake can also hinder this conversion process, meaning an over-reliance on plant sources alone can leave you short on omega 3 overall. A carefully balanced diet, or a supplement if you're vegan, vegetarian, or don't eat fish regularly, is worth considering. Long-chain fatty acids like EPA and DHA support inflammation reduction and heart health more directly than ALA does on its own.
How to Find Out If You Have Healthy Omega 3 Levels
Could symptoms you've been experiencing be related to your omega 3 levels? A registered nutritionist may be able to advise or refer you for testing, though waiting lists for NHS services can be lengthy. If you'd rather not wait, at-home kits are available that let you test your omega 3 and 6 levels in your own time – a simple finger-prick blood sample sent for full laboratory analysis, with results typically back within a few days.
Your results give you a clear, accessible basis for fine-tuning your diet and balancing your omega 3 intake, supporting your health and wellbeing going forward.
