Are You Getting Enough Omega-3s?

Unless you are eating fatty fish on a regular basis, you may not be getting enough EPA and DHA on a daily basis. 

Your body uses these fats to build cells, especially in the brain and eyes, and it’s production of these long-chain omega-3 fatty acids is limited. A blood test called the omega-3 index is the most reliable way to know if you’re getting enough.

Key Takeaways

• In national CDC data, 98% of Americans had an omega-3 index below the optimal level.(CDC, 2026)

• Plant foods like flax and chia contain ALA, which your body converts into EPA and DHA but likely in limited amounts due to competing pathways using the same enzymes.

• Ocean-caught fish is the best food source because it already contains EPA and DHA.

How common are low omega-3 levels?

Low omega-3 levels are common in the United States. EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) are the two long-chain omega-3 fats found mainly in fish, and most people have less of them than research links to good health.

Omega-3 status is measured with the omega-3 index. The index adds up the EPA and DHA levels in red blood cells. Results are grouped as undesirable (below 4%), intermediate (4 to 8%), and optimal (above 8%) (CDC, 2026).

A 2026 CDC report used national survey data from August 2021 to August 2023. More than half of Americans had an undesirably low index, below 4%, and 98% were below the optimal range (CDC, 2026).

What do omega-3s do in the body?

EPA and DHA are building blocks of cell membranes, the outer layer of every cell in the body. DHA is especially concentrated in the brain, where it helps build the outer layer of brain cells, and in the retina, the light-sensing layer at the back of the eye. Your body also uses EPA and DHA to make signaling molecules that help cells communicate (Office of Dietary Supplements, n.d.).

Who tends to have lower omega-3 intake?

People who rarely eat fatty fish and people who rely on plant sources of omega-3 tend to have lower levels, as conversion is limited. National data also show differences by age, smoking, and education.

People who rarely eat fatty fish

Fatty fish is the main food source of EPA and DHA. Salmon, sardines, mackerel, and herring supply the most. Few other foods contain meaningful amounts, so people who rarely eat these fish get little EPA and DHA from their diet.

People who rely on plant sources of omega-3

Flaxseed, chia seeds, walnuts, and canola oil contain ALA (alpha-linolenic acid), a different omega-3. Your body has to convert ALA into EPA and DHA, and it doesn’t do this efficiently.

A 2005 review of human studies found that the body converts a limited amount of ALA to EPA in men and very little further to DHA, while women convert more (Burdge & Calder, 2005). A 2002 review found that less than 5% of ALA becomes DHA, and that the amount depends on how much omega-6 fatty acids are in the diet (Brenna, 2002).

Omega-6 fats compete with ALA for the same conversion process. They come from vegetable oils and processed foods and make up far more of most diets than omega-3. This means you can eat plenty of plant omega-3 and still test low.

A 2006 study of 20 adults compared fish oil with flaxseed oil over 8 weeks. After 8 weeks of fish oil, the average omega-3 index reached 7.8%. Flaxseed oil raised EPA somewhat but did not change DHA (Cao et al., 2006).

Ocean-caught fish is the best food source because it already contains EPA and DHA, so no conversion is needed. Fish get these fats from algae at the base of the ocean food chain.

Age, smoking, and education

In the 2026 CDC data, older adults, people with more education, and nonsmokers tended to have higher omega-3 index results (CDC, 2026). The report did not look at why.

How the omega-3 index test works

The omega-3 index test measures how much EPA and DHA has built up in your red blood cells. Red blood cells live about 120 days, so the result shows your intake over the past few months. That makes it more reliable than trying to remember what you ate.

You can’t tell your omega-3 status from symptoms. To know your level, you need the test. A healthcare provider can order it, or you can use an at-home finger-prick kit.

Food sources of EPA and DHA

Ocean-caught fatty fish is the richest food source of EPA and DHA. The values below come from the NIH Office of Dietary Supplements (Office of Dietary Supplements, n.d.).

The plant foods show bigger numbers, but all of it is ALA. Only a small share of that becomes EPA, and even less becomes DHA.

When to talk to a healthcare provider

Talk to a healthcare provider if you have ongoing symptoms that concern you. Ask about an omega-3 index test if you want to know your status. Check with your provider before starting any supplement, especially if you take medications or have surgery coming up.

Rho’s Liquid Omega-3 Supplement

Rho Liquid Omega-3 is a liquid fish oil that provides EPA and DHA, the omega-3 forms your body can effectively use. It helps you maintain healthy omega-3 levels.* It uses a micellar delivery system, so there’s no fishy taste and no fish burps.

The formula includes tocopherols, forms of vitamin E that help protect the fish oil from oxidation. Oxidation is the process that makes fish oil go stale. See the product label for serving information.

Contains fish.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Frequently asked questions

How do I know if my omega-3 levels are low?

A blood test called the omega-3 index is the most reliable way. It measures EPA and DHA in your red blood cells and reflects your intake over the past few months.

What is a good omega-3 index score?

An index above 8% is considered optimal. An index between 4% and 8% is intermediate, and below 4% is undesirable (CDC, 2026).

Can you test omega-3 levels at home?

Yes. At-home kits use a finger-prick blood sample that you mail to a lab. A healthcare provider can also order the test.

Does a plant-based diet provide enough EPA and DHA?

Plant foods provide ALA, not EPA or DHA. The body converts only a small share of ALA to EPA, and very little to DHA (Burdge & Calder, 2005).

How long does it take to raise omega-3 levels?

Levels start to rise within weeks, but a full picture takes a few months. A 2013 trial in healthy adults found that the omega-3 index rose with the amount of EPA and DHA taken. A person’s starting index, age, sex, and activity level also affected the results (Flock et al., 2013). Because red blood cells last about 120 days, retesting after 3 to 4 months gives a fair comparison.

References

Centers for Disease Control and Prevention. (2026). Over half of Americans have too-low omega-3 fatty acid levels [Fact sheet]. 2026 CDC Nutrition Report. https://www.cdc.gov/nutrition-report/media/pdfs/2026/06/Factsheet-Omega-3-508.pdf

Office of Dietary Supplements. (n.d.). Omega-3 fatty acids: Fact sheet for health professionals. National Institutes of Health. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/

Burdge, G. C., & Calder, P. C. (2005). Conversion of α-linolenic acid to longer-chain polyunsaturated fatty acids in human adults. Reproduction Nutrition Development, 45(5), 581–597. https://doi.org/10.1051/rnd:2005047

Brenna, J. T. (2002). Efficiency of conversion of alpha-linolenic acid to long chain n-3 fatty acids in man. Current Opinion in Clinical Nutrition and Metabolic Care, 5(2), 127–132. https://doi.org/10.1097/00075197-200203000-00002

Cao, J., Schwichtenberg, K. A., Hanson, N. Q., & Tsai, M. Y. (2006). Incorporation and clearance of omega-3 fatty acids in erythrocyte membranes and plasma phospholipids. Clinical Chemistry, 52(12), 2265–2272. https://doi.org/10.1373/clinchem.2006.072322

Flock, M. R., Skulas-Ray, A. C., Harris, W. S., Etherton, T. D., Fleming, J. A., & Kris-Etherton, P. M. (2013). Determinants of erythrocyte omega-3 fatty acid content in response to fish oil supplementation: A dose-response randomized controlled trial. Journal of the American Heart Association, 2(6), e000513. https://doi.org/10.1161/JAHA.113.000513

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.