Inflammation, fatigue, brain fog, low mood — could the fats you eat be part of the problem? In today’s world, our diets are overflowing with omega-6 fats from vegetable oils and processed foods, while omega-3s — the fats that calm inflammation and support brain health — are in short supply.
This imbalance is now linked to many of the chronic conditions on the rise today, from heart disease and arthritis to anxiety and cognitive decline. It’s not that omega-6 is “bad”, it’s that too much of it drowns out the benefits of omega-3, leaving the body in a state of constant low-grade inflammation.
The good news? Restoring balance is possible. In this month’s blog, we’ll explore why omega-3 is essential, the role it plays in brain and cardiovascular health, how modern diets disrupt the omega-6 to omega-3 ratio, and how functional medicine testing can identify whether your body is truly making the most of these vital fats.
Over 90% of UK adults fail to meet recommended omega-3 intake from oily fish.
What Are Omega-3 Fatty Acids?
Omega-3 fatty acids are a family of polyunsaturated fats that play a critical role in human health, growth, and disease prevention. They are found in every cell membrane and act as raw materials for signalling molecules that influence inflammation, blood pressure, immunity, and even mood.
The three most important types of omega-3s for human health are:
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ALA (alpha-linolenic acid): Found mainly in flaxseeds, chia seeds, hemp, and walnuts. ALA is the “parent” omega-3 but must be converted into EPA and DHA to have most of its benefits.
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EPA (eicosapentaenoic acid): Found in oily fish and algae; best known for its anti-inflammatory properties and cardiovascular support.
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DHA (docosahexaenoic acid): Found in fish and algae; a structural fat critical for the brain, eyes, and nervous system. DHA makes up a large proportion of the brain’s grey matter.
Together, these fatty acids help regulate inflammation, maintain healthy cell membranes, and protect the brain and heart throughout life.
Why Are Omega-3s Called Essential?
Omega-3 fatty acids are called essential because the body cannot produce them in sufficient amounts on its own. They must be obtained from diet or supplementation to meet daily needs.
While ALA can technically be converted into EPA and DHA, this conversion is highly inefficient — often less than 5–10% in most people. This makes direct dietary sources of EPA and DHA, such as oily fish or algae oil, particularly important.
What Are the Evidence-Based Benefits of Omega-3 Fatty Acids?
Decades of clinical research show that omega-3 fatty acids influence nearly every system in the body — from the heart and brain to the immune system, joints, eyes, and even mood regulation. Adequate intake is therefore linked not just to reduced risk of chronic disease, but also to improved quality of life and healthy ageing.
1. Cardiovascular Health
Helps maintain normal blood pressure, supports triglyceride balance, and protects overall heart health.
A meta-analysis of 38 trials (149,051 adults) found that omega‑3 supplementation significantly reduced cardiovascular mortality (−7%), non-fatal myocardial infarction (−13%), coronary heart disease events (−9%), major adverse cardiovascular events (−5%), and revascularization (−9%).
2. Brain & Mental Health
DHA is a structural component of the brain. Supplementation may improve mood, reduce depression, and support cognitive performance in later life.
For cognitive function, a 2022 review found that omega‑3 fatty acids including DHA and EPA improved learning, memory, and brain blood flow, especially in older adults or those with low omega‑3 intake.
Regarding mental health, among nutrient supplements evaluated in a 2019 meta-review published in World Psychiatry, EPA-rich omega‑3 formulations displayed the strongest evidence for reducing depressive symptoms as an adjunctive treatment.
3. Pregnancy & Infant Development
DHA is vital for foetal brain and eye development. Supplementation during pregnancy and breastfeeding is often recommended.
A 2024 review reported that DHA and EPA supplementation during pregnancy improved neurological outcomes in babies — enhancing language, memory, hand coordination, visual acuity, and even reduced risks like preterm birth and preeclampsia.
4. Anti-Inflammatory Effects
EPA and DHA help regulate inflammation, benefiting conditions such as arthritis, cardiovascular disease and chronic inflammatory disorders.
A 2019 meta-analysis in Scientific Reports found that omega-3 supplements helped people with diabetes and heart disease by lowering harmful blood fats (triglycerides) and certain proteins linked to inflammation (Apo AII) compared to those who didn’t take them.
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How Do Omega-3s Affect Brain Health?
Our brains are almost 60% fat, and DHA alone makes up around 40% of the polyunsaturated fats in the brain. This structural fat is concentrated in the grey matter and the retina, where it ensures that cell membranes remain flexible and efficient at transmitting signals. In practical terms, DHA is what helps nerve cells “talk” to each other effectively.
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In children, omega-3 intake supports learning, behaviour, and brain development. Several studies show improved reading, memory, and attention in children who regularly consume fish or DHA supplements.
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In adults, higher EPA and DHA levels are linked to better concentration, working memory, and faster information processing. EPA, in particular, has been shown to play a key role in mood regulation, with benefits for stress resilience and anxiety.
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In older adults, omega-3 supplementation may slow age-related cognitive decline and reduce the risk of dementia. Low DHA levels are consistently associated with smaller brain volume and accelerated cognitive ageing.
Omega-3 fatty acids are fundamental to brain health across the lifespan — fuelling development in infancy, supporting focus and mood in adulthood, and protecting memory and cognition in later years.
The Omega-6 to Omega-3 Imbalance
Both omega-6 and omega-3 fatty acids are essential, but the balance between them matters. Historically, humans consumed a ratio close to 1:1 or 2:1. Modern Western diets now average 15:1 or higher, heavily weighted towards omega-6.
Omega-6 fats, found in vegetable oils (sunflower, corn, soybean) and processed foods, are not harmful on their own. However, excess omega-6 promotes pro-inflammatory pathways, whereas omega-3s help regulate and calm inflammation.
This imbalance is now recognised as a factor in cardiovascular disease, arthritis, obesity, mood disorders, and cognitive decline. Restoring balance requires both increasing omega-3 intake and reducing reliance on processed, omega-6-rich foods.
Why Balance Matters
Both omega-3s and omega-6s use the same enzymes to convert into their active forms:
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Omega-3: ALA → EPA → DHA
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Omega-6: Linoleic acid (LA) → Arachidonic acid (AA)
When omega-6 intake is high, it blocks omega-3 conversion and increases production of AA, which fuels inflammation.
This explains why simply eating plant-based omega-3s (like flax or chia) may not be enough in high omega-6 diets. Direct sources of EPA and DHA from fish or algae oil, combined with reducing processed oils, are the most effective strategies.
Should You Take an Omega-3 Supplement?
Not everyone needs to take an omega-3 supplement, but for many people it can be beneficial. You may want to consider supplementation if you:
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Eat little or no oily fish
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Are pregnant or breastfeeding (always under professional guidance)
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Have cardiovascular risk factors or chronic inflammatory conditions
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Are an older adult looking to protect brain and eye health
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Have a restricted diet (for example, children or adults who avoid fish)
On the other hand, supplementation may not be necessary or recommended if you:
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Already eat at least two servings of oily fish per week
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Are taking blood-thinning medication as Omega-3s have mild blood-thinning effects. Those on medications such as aspirin, warfarin, clopidogrel, or antihypertensives should seek professional guidance
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Have fish or shellfish allergies — in which case, algae-based omega-3 is a safe and effective alternative
What Affects Omega-3 Absorption & Utilisation?
Getting enough omega-3 through diet or supplementation is only part of the picture — what your body can actually absorb and use depends on several factors.
Nutrient Cofactors
Omega-3 metabolism relies on enzymes that need other nutrients to work properly. Key cofactors include:
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Magnesium and zinc – activate enzymes involved in fatty acid conversion.
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B-vitamins (B6, B3) and vitamin C – support pathways that turn ALA into EPA and DHA.
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Biotin and adequate protein – provide building blocks for fatty acid synthesis and transport.
If any of these are lacking, your body may not fully utilise the omega-3s you consume, even if your intake is otherwise sufficient.
Lifestyle & Health Cofactors
Several common issues can further reduce omega-3 effectiveness:
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Excess alcohol intake impairs enzyme activity and increases oxidative stress.
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Poorly controlled diabetes or insulin resistance can interfere with fatty acid metabolism.
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High intake of processed vegetable oils and trans fats increases omega-6 competition, blocking conversion of ALA into EPA and DHA.
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Ageing naturally reduces enzyme efficiency, making direct dietary DHA and EPA more important later in life.
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Genetic variations (such as FADS1 and FADS2 polymorphisms) can significantly limit an individual’s ability to convert ALA into EPA and DHA.
Achieving optimal omega-3 levels isn’t just about how much you eat, it’s also about whether your body has the right nutritional support and metabolic conditions to process and use it effectively.
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How to Choose the Right Omega-3 Supplement: A Functional Medicine Approach
When it comes to supplementation, quality and personalisation matter. Not all omega-3 products are created equal, and choosing the right one can make the difference between minimal benefit and meaningful impact.
What To Look For In A Supplement
- Source: Fish oil, krill oil, or algae oil (a vegan-friendly option).
- Purity: Products should be third-party tested for heavy metals, PCBs, and toxins.
- Form: Triglyceride or re-esterified triglyceride forms are better absorbed than ethyl esters.
- Freshness: Omega-3 oils are prone to oxidation, so high-quality products include antioxidants such as vitamin E.
- Transparency: Labels should clearly state the exact amounts of EPA and DHA per serving.
Why Personalisation Matters
Supporting health with omega-3s is not just about taking a capsule. A functional medicine approach looks deeper:
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Individual needs are assessed through functional testing, such as the Omega-3 Index, to determine baseline levels.
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Nutrient cofactors are addressed to ensure the body can metabolise and use omega-3s effectively.
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Balance is restored between omega-3 & omega-6 fats, reducing inflammation and supporting long-term health.
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Diet & supplementation plans are tailored to the individual’s unique health picture, lifestyle, and goals.
For more information on our range of health tests, personalised nutrition and lifestyle plans and targeted supplement protocols tailored to your needs by our practitioners visit our How It Works page.
YOUR HEALTH. YOUR CHOICE.
Omega-3 fatty acids are essential across the lifespan, from infant brain development to protecting cardiovascular and cognitive health in older age. But utilisation depends on diet, cofactors, lifestyle, and genetics. In today’s high omega-6 world, restoring balance is more important than ever. Functional testing provides the missing piece, helping identify not just intake, but actual absorption and utilisation.
At Nutrition Diets Clinic, our functional medicine approach goes far beyond generic advice by considering your unique genetic makeup, diet, environmental exposures, lifestyle factors, and health history to get to the root cause of your health concerns.
1) Expert one-to-one therapy
2) Personalised nutrition and lifestyle plans
3) Easy, at-home functional testing
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