Omega 6:3 Ratio Blood Test: Normal Ranges, Causes & What Your Results Mean

What Is the Omega 6:3 Ratio?

The omega 6:3 ratio is a measure of the balance between two families of essential polyunsaturated fatty acids (PUFAs) in your blood: omega-6 fatty acids and omega-3 fatty acids. Both are termed "essential" because the human body cannot synthesise them — they must be obtained through diet. However, the relative proportions in which you consume them have profound effects on inflammation, cardiovascular health, brain function, and chronic disease risk.

Omega-6 fatty acids — principally linoleic acid (LA) and arachidonic acid (AA) — are found abundantly in vegetable oils (sunflower, corn, soybean), processed foods, margarine, and conventionally raised meat. When metabolised, arachidonic acid gives rise to pro-inflammatory eicosanoids (prostaglandins, thromboxanes, leukotrienes) that promote inflammation, blood clotting, and vasoconstriction. These processes are essential in acute injury and infection but become harmful when chronically elevated.

Omega-3 fatty acids — principally alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) — are found in oily fish, flaxseeds, chia seeds, walnuts, and algae. EPA and DHA produce anti-inflammatory and inflammation-resolving mediators (resolvins, protectins, maresins) that counterbalance the effects of omega-6-derived eicosanoids.

The omega 6:3 ratio reflects the dietary balance between these competing pathways. A lower ratio indicates a more anti-inflammatory state. Ancestral human diets are estimated to have had a ratio of approximately 1:1 to 4:1. The modern Western diet, however, typically delivers a ratio of 15:1 to 25:1 — heavily skewed toward omega-6 due to the widespread use of vegetable oils and processed foods. This imbalance is increasingly recognised as a contributor to chronic inflammatory conditions, including cardiovascular disease, metabolic syndrome, autoimmune disorders, and certain cancers.

Why Is the Omega 6:3 Ratio Tested?

Testing the omega 6:3 ratio provides valuable insight into your inflammatory status and dietary fatty acid balance. Reasons for testing include:

• Cardiovascular risk assessment: An elevated omega 6:3 ratio is associated with increased risk of coronary heart disease, stroke, and atherosclerosis. Optimising this ratio is considered a modifiable cardiovascular risk factor.
• Chronic inflammation investigation: If you have conditions driven by inflammation — such as rheumatoid arthritis, inflammatory bowel disease, psoriasis, or asthma — assessing your omega 6:3 ratio can guide dietary interventions.
• Metabolic health: Insulin resistance, type 2 diabetes, and non-alcoholic fatty liver disease are all associated with elevated omega-6 intake relative to omega-3.
• Mental health: Emerging evidence links a high omega 6:3 ratio to increased risk of depression, anxiety, and cognitive decline. EPA and DHA are critical structural components of brain cell membranes.
• Pregnancy and child development: DHA is essential for foetal brain and retinal development. Ensuring an adequate omega-3 intake (and a favourable ratio) during pregnancy is recommended by NICE.
• Monitoring dietary changes or supplementation: If you have increased oily fish consumption or started omega-3 supplements, repeat testing confirms whether your ratio has improved.
• Skin conditions: Eczema, dry skin, and inflammatory skin conditions may be associated with an unfavourable fatty acid balance.

Normal Ranges

The omega 6:3 ratio is expressed as a simple ratio (e.g., 3:1 or 8:1). There is no single universally agreed reference range, but the following thresholds are widely used in clinical nutrition and functional medicine:

Omega 6:3 Ratio	Interpretation	Clinical Context
1:1 to 3:1	Optimal	Anti-inflammatory state; associated with lowest cardiovascular risk
3:1 to 6:1	Acceptable	Reasonable balance; most health-conscious diets fall here
6:1 to 10:1	Suboptimal	Mildly pro-inflammatory; dietary modification recommended
10:1 to 15:1	Elevated	Significantly pro-inflammatory; associated with increased disease risk
> 15:1	High	Typical Western diet; strongly associated with chronic inflammatory conditions

Some laboratories and testing services also report the Omega-3 Index — the percentage of EPA and DHA in red blood cell membranes — which is a complementary measure. An Omega-3 Index above 8% is considered cardioprotective, while below 4% is associated with elevated cardiovascular risk.

What Does a High Omega 6:3 Ratio Mean?

A high omega 6:3 ratio (above 6:1) indicates a pro-inflammatory dietary pattern and is associated with:

• Excessive vegetable oil consumption: Sunflower oil, corn oil, soybean oil, and safflower oil are extremely rich in omega-6 linoleic acid. These are the dominant cooking oils in many processed foods, restaurant meals, and ready meals.
• High processed food intake: Crisps, biscuits, pastries, margarine, salad dressings, and fast food typically contain large amounts of omega-6-rich oils.
• Insufficient oily fish intake: Many UK adults eat far less than the recommended two portions of fish per week (one of which should be oily), resulting in inadequate EPA and DHA intake.
• Conventionally raised meat: Grain-fed livestock accumulate more omega-6 and less omega-3 in their tissues compared to grass-fed or pasture-raised animals.
• Increased cardiovascular risk: A ratio above 10:1 has been consistently associated with higher rates of coronary events, arterial inflammation, and endothelial dysfunction.
• Chronic inflammatory conditions: Rheumatoid arthritis, inflammatory bowel disease, and psoriasis may be exacerbated by a high omega 6:3 ratio.
• Metabolic syndrome: Insulin resistance and visceral obesity are linked to excessive omega-6 consumption relative to omega-3.
• Mood disorders: Populations with higher omega 6:3 ratios have higher rates of depression and anxiety.

What Does a Low Omega 6:3 Ratio Mean?

A low omega 6:3 ratio (below 3:1) is generally desirable and indicates a well-balanced or omega-3-rich dietary pattern:

• Regular oily fish consumption: Eating salmon, mackerel, sardines, herring, or anchovies 2–3 times per week typically produces an excellent omega 6:3 ratio.
• Omega-3 supplementation: Fish oil, krill oil, or algal oil supplements can substantially lower the ratio.
• Mediterranean or Japanese dietary patterns: Both emphasise seafood, olive oil (low in omega-6 compared to seed oils), and plant-based foods, producing favourable omega 6:3 ratios.
• Reduced processed food intake: Minimising intake of vegetable oil-laden processed foods naturally reduces omega-6 consumption.
• Grass-fed meat consumption: Pasture-raised animals have a more favourable fatty acid profile than grain-fed livestock.
• Anti-inflammatory state: A low ratio is associated with reduced systemic inflammation, better endothelial function, and lower cardiovascular risk.

It is theoretically possible to have an excessively low ratio through very high omega-3 supplementation. At extremely high doses (above 3g EPA+DHA daily), there may be a mildly increased bleeding risk, though this is rarely clinically significant. The NHS and NICE do not identify a firm lower limit for the ratio.

How to Improve Your Omega 6:3 Ratio

Improving your ratio requires a two-pronged approach: increasing omega-3 intake while reducing omega-6 consumption.

Increase Omega-3 Intake

• Eat oily fish 2–3 times per week: Salmon, mackerel, sardines, herring, anchovies, and trout are the best sources of EPA and DHA. The NHS recommends at least one portion of oily fish per week, but two to three portions will have a greater effect on your ratio.
• Choose high-quality omega-3 supplements: If you do not eat fish, a daily fish oil supplement providing 1,000–2,000 mg of combined EPA and DHA is a reasonable starting point. Algal oil supplements are an excellent plant-based alternative for vegans.
• Include plant-based omega-3 sources: Flaxseeds (ground or as oil), chia seeds, hemp seeds, and walnuts provide ALA, which is partially converted to EPA and DHA in the body (though conversion efficiency is low, at approximately 5–10%).
• Choose grass-fed meat and free-range eggs: These contain more omega-3 than their conventionally produced counterparts.

Reduce Omega-6 Intake

• Switch cooking oils: Replace sunflower, corn, and soybean oils with extra virgin olive oil, rapeseed oil, avocado oil, or coconut oil — all of which have more favourable omega 6:3 profiles.
• Minimise ultra-processed foods: Ready meals, takeaways, crisps, biscuits, and fast food are major sources of omega-6 vegetable oils.
• Read labels: Look for "sunflower oil," "vegetable oil," or "soybean oil" in ingredient lists and choose alternatives where possible.
• Reduce margarine use: Many margarines and spreads are made from omega-6-rich seed oils. Butter in moderation or olive oil-based spreads are better options.
• Cook from scratch: Home-cooked meals give you control over which oils and fats you use.

Monitoring and Maintenance

• Retest after 3–6 months: Red blood cell fatty acid composition changes gradually. Allow at least three months of dietary modification before repeating the test.
• Be consistent: Occasional fish meals have less impact than regular, sustained changes to your overall dietary pattern.

When Should You Get Tested?

Consider an omega 6:3 ratio test if:

• You have a family history of cardiovascular disease and want to assess modifiable risk factors.
• You suffer from a chronic inflammatory condition (arthritis, IBD, psoriasis, asthma).
• You eat little or no oily fish and suspect your omega-3 intake may be inadequate.
• You consume a lot of processed foods, takeaways, or meals cooked in vegetable oils.
• You are pregnant or planning pregnancy and want to optimise DHA intake for foetal development.
• You experience persistent low mood, brain fog, or cognitive difficulties.
• You have dry skin, eczema, or inflammatory skin conditions.
• You have started omega-3 supplementation and want to monitor its effect.

Which Lola Health Tests Include the Omega 6:3 Ratio?

Assessing your fatty acid balance is an important part of understanding your inflammatory and cardiovascular health. Lola Health offers the following panels:

• Peak Insights — our most comprehensive test, covering omega fatty acid balance alongside an extensive range of cardiovascular, metabolic, and inflammatory biomarkers.
• Vital Check — a thorough wellness panel that includes key inflammatory and metabolic markers.
• Core Health — an essential health check covering fundamental markers for everyday wellbeing.

All Lola Health tests use venous blood draws for clinical-grade accuracy. Your results are reviewed by qualified healthcare professionals who provide personalised dietary recommendations to optimise your omega 6:3 ratio.