Over 60% of people are low in Omega-3s - are you getting enough?

Our analysis of people who took a Medichecks blood test over the past year – including customers who took our new Skin IQ profile – shows that more than 60% had low omega-3 levels. It’s a striking finding, especially given how many people believe they eat a healthy, balanced diet. 

Known as essential fatty acids, omega-3, along with omega-6, is a ‘good’ fat that is important for your overall health, but it’s particularly crucial for the heart, brain, and skin. Your body cannot produce omega-3 fatty acids; they can only be obtained from diet or supplementation. Our nationwide data suggests many people are unintentionally falling short [1]. 

The good news? You can support your omega-3 levels through a healthy diet and, where appropriate, targeted supplementation. Below, we’ll explain who’s most at risk, how to recognise low intake patterns, and the practical steps to improve your levels safely.
 

In this blog we cover:

• What does omega-3 do?
• What is the omega-3 index?
• SMASH: the answer to low omega-3
• How much omega-3 per day do you need?
• Should you worry about mercury intake?
• Omega-3 supplements
• Who’s likely to have low omega-3?
• Omega-3 action plan

 

What does Omega-3 do?

 

The three main types of omega-3 are: 

• Eicosapentaenoic acid (EPA)
• Docosahexaenoic acid (DHA), found mainly in oily fish 
• Alpha-linolenic acid (ALA) found in plants, nuts and seeds

Omega-3s are essential fats that support your heart, brain, mood, and skin. Here’s more detail on how they affect each of those areas:

Cell structure and inflammation reduction

EPA and DHA are woven into immune-cell membranes and help make specialised pro-resolving mediators, such as resolvins and protectins. These compounds play a key role in switching off everyday inflammation. 

Heart health

Omega-3s help lower triglycerides – the primary type of fat found in your blood, support regular heart rhythm, and may lower cardiovascular risk when your overall lifestyle is in check. 

Brain, eyes, mood

DHA is concentrated in the brain and retina, and regular intake supports normal cognitive and visual function throughout life. 

Pregnancy and early life

Maternal intake contributes to the baby’s brain and eye development. Safe, low-mercury fish or algae DHA are especially useful in these scenarios. 

Skin

By supporting the skin barrier and tempering inflammation, omega-3s can help alleviate dryness and enhance overall skin resilience. 

Omega-3 is included in our popular Skin IQ Blood Test. This test includes 50 biomarkers in total which help you support your skin and overall health with real insights you can use to optimise your skincare, diet, and lifestyle choices.

Read how omega-3s play a role in healthy skin in our article. 

What is the Omega-3 index
 

The omega-3 index is the percentage of EPA and DHA in your red blood cell membranes. It reflects your longer-term omega-3 status – roughly the last two to three months, rather than just what you ate this week.

The index is typically interpreted with cut-offs: 

• Below 4% = low

• 4–8% = mid-range

• 8% or above = ideal [2]

Check your omega-3 index with our Omega-3 and -6 Blood Test. 

SMASH - the answer to low Omega-3
 

The simplest way to raise EPA and DHA levels is to eat oily fish regularly – think SMASH. 

SMASH stands for sardines, mackerel, anchovies, salmon, and herring. NHS guidance suggests two portions of fish a week, including one oily fish [3]. Naturally rich in EPA and DHA, these species are good, healthy choices. 

Our survey [1] revealed that over 60% of respondents had never heard of SMASH, but among those who had, around two-thirds regularly include oily fish in their diets. 

ALA is found in many plants, seeds, and nuts, and is another way to increase your omega-3 levels. 

ALA-rich plant sources include:

• Spinach, broccoli, sprouts, peas, and tomatoes

• Oils, such as flaxseed, rapeseed, and soybean

• Seeds, including flaxseed, chia, hemp, perilla, and kiwi fruit seeds

• Walnuts

• Eggs from chickens fed an omega-3-enriched diet

Algae-based omega-3 – the fish-free route to EPA and DHA

Algae are the source of marine omega-3s – fish get their EPA and DHA by eating algae and other algae-eating organisms. Oils from tank-grown algae oils deliver these same omega-3s directly, making them a wise choice for vegans, vegetarians, and anyone who doesn’t eat fish.

You should aim to include around: 

• One to two tablespoons of walnuts, ground flax or chia seeds, or 
• 250 – 500 mg of algae oil daily

How much Omega-3 per day do you need?
 

For general health, most authorities agree on a range of 250–500 mg per day for adults [4]. In the UK, the advice is framed as “at least two portions of fish a week, including one of oily fish,” which equates to roughly 0.45 g per day of EPA and DHA when averaged across the week [5].

How much EPA and DHA are in SMASH fish portions?

 

Type of fish	Portion size	Approximate amount of EPA and DHA
Salmon	120 g	1.5 – 2.0 g
Mackerel	100 g	1.0 – 1.8 g
Anchovies	30 g	0.5 – 0.9 g
Sardines (tinned)	90g	1.0 – 1.5 g
Herring	100 9	1.2 – 1.7 g

Should you worry about mercury intake?
 

Mercury from natural sources and pollution settles in water, where microbes turn it into methylmercury. It then accumulates and magnifies up the food chain, so large, long-lived fish, such as sharks, swordfish, and the bigger species of tuna, carry the highest levels.

Most people don’t need to worry too much about mercury in their diets, provided they prioritise the SMASH species over those larger predatory fish.

However, if you’re pregnant, breastfeeding, or feeding young children, the advice is to avoid eating any shark and swordfish, limit tuna to a maximum of four tins per week and eat no more than two portions a week of oily fish [6]. 

If you’re concerned about your mercury levels, our Mercury Blood Test offers a reliable, doctor-reviewed result. 

Omega-3 supplements
 

Fish oil supplements can supply EPA and DHA if you’re deficient in omega-3, with cod liver or red krill oil being popular. Oils derived from algae are suitable for vegetarians, vegans, or non-fish eaters, while flax or linseed oil capsules contain ALA. 

Check the EPA and DHA levels per serving and take with a meal to support absorption. 

Pregnancy note:

If you use cod-liver oil and are pregnant or trying to conceive, watch the vitamin A total as excess retinol can be harmful in pregnancy, so follow UK advice and avoid high-vitamin-A supplements [7].

Who's likely to have low Omega-3?
 

Some poeple are more likely to have low omega-3 than others. 

People who may have an omega-3 deficiency are those who:

• Rarely eat oily fish

• Eat mostly plant-based without supplementing DHA/EPA

• Have low intake of ALA-rich foods

• Struggle with restrictive diets

• Are children (who often avoid oily fish)

• Pregnant and breastfeeding women also have higher DHA needs for the baby’s brain and eyes, so without consuming enough fish, their omega-3 levels can be sub-optimal [8].

Signs that you have low omega-3

It can be challenging to identify low omega-3 levels, as the signs are often nonspecific, such as rough, dry skin, brittle nails, fatigue, and mood swings [9]. The best indicators of a lack of omega-3 are to examine your diet, especially if you’re pregnant, or to get a blood test.

Omega-3 action plan
 

Because symptoms of low omega-3 are non-specific, a simple way to know where you stand is to take a baseline blood test that reports the omega-3 index. Then make targeted dietary changes.

Red blood cells have a life cycle of two to three months, so it’s recommended to re-take your omega-3 blood test then to assess if your dietary changes have made a difference. The test – change – test cycle replaces any guesswork and shows the difference a good diet can make to your omega-3 levels. 

---

 

References

1. Medichecks. Annual Health Report 2025: Survey Findings (n=940). Nottingham, UK: Medichecks; 2025
2. Harris, W.S. (2010), The omega-3 index: clinical utility for therapeutic intervention. Current Opinion in Clinical Nutrition and Metabolic Care, 13(2), pp. 121–126. 
3. NHS (2022) Fish and shellfish. NHS Live Well. (Accessed 15 October 2025)
4. WHO/FAO (2010; codified 2016) Proposed Nutrient Reference Values for EPA+DHA (NRV-NCD = 250 mg/day). FAO/WHO Codex Alimentarius background paper. (Accessed 16 October 2025)
5. Derbyshire, E. (2019) Oily fish and omega-3s across the life stages. Frontiers in Nutrition, 6, 165. (Accessed 15 October 2025)
6. NIH ODS (2020) Omega-3 Fatty Acids - Health Professional Fact Sheet. National Institutes of Health, Office of Dietary Supplements. (Accessed 16 October 2025)
7. NHS (2020) Foods to avoid in pregnancy. National Health Service. (Accessed 26 November 2025)
8. nidirect (n.d.) Healthy eating for children (Accessed: 26 November 2025)
9. Koletzko, B., Cetin, I. and Brenna, J.T. (on behalf of the Perinatal Lipid Intake Working Group) (2007) Dietary fat intakes for pregnant and lactating women: a consensus statement about intakes of long-chain polyunsaturated fatty acids. Annals of Nutrition and Metabolism, 51(2), pp. 119–128. (Accessed 15 October 2025)