Omega-3 and inflammation

At a glance

Omega-3 fats take part in cell signalling. Clinical studies answer narrower questions about particular markers, populations and outcomes, and the results vary by what researchers measured. ^[2] ^[3] ^[4] ^[5]

What is inflammation?

Inflammation is part of the body’s response to injury or infection. A cut may become warm or swollen while immune cells help protect and repair the area. This short-lived response is often called acute inflammation. Chronic inflammation can persist and contribute to tissue damage in some conditions. ^[1]

Inflammation also comes up in discussions of autoimmune disease, where the immune system reacts against the body’s own tissues. Rheumatoid arthritis is one example. The cause, affected tissue and treatment needs differ across inflammatory conditions, so the name of the condition matters when reading about research. ^[1] ^[6] ^[7]

Why do researchers study omega-3?

The body uses fats including EPA and DHA to make or influence signalling molecules involved in immune responses. Studying these pathways helps researchers understand how a response starts, changes and settles. This gives scientists a reason to investigate omega-3 in people, where diet, existing health conditions and medicines can all influence the results. ^[2]

Researchers might test whether a blood marker changes, whether a person’s symptoms improve or whether fewer people receive a new diagnosis. Each outcome answers a different question. For example, a blood marker measured at a particular visit tells us about that measurement, while a study of new diagnoses follows participants over time. ^[3] ^[4]

What did the VITAL trial find?

One VITAL study looked at three blood markers of systemic inflammation after one year. Among the older adults studied, marine omega-3 produced no clear reduction in those markers compared with placebo. The finding describes that study population, dose, time point and set of measurements. ^[3]

A separate analysis measured new, medically confirmed autoimmune diagnoses across several conditions. During the randomised trial, the difference between the marine omega-3 and placebo groups was statistically inconclusive. A follow-up that added two years of observation found fewer combined new diagnoses among those originally assigned omega-3. Those analyses looked at new diagnoses in older adults. How a diet or intervention affects symptoms in someone already living with an inflammatory disease requires different evidence. ^[4] ^[5]

What this means for everyday decisions

If you live with rheumatoid arthritis, NICE says there is little or no evidence of lasting benefit from complementary therapies and advises keeping conventional treatment in place. NICE notes that people interested in changing their diet may consider a Mediterranean-style eating pattern, with a variety of vegetables, fruit, fish and other foods. Any decisions about medication or monitoring belong with the team managing the condition. ^[6]

If swelling or stiffness is new, keeps recurring or interferes with everyday tasks, describe which joints are affected, how long stiffness lasts and whether movement changes it. A GP can assess what could be causing the symptoms and decide whether tests or referral are appropriate. ^[7]

Common questions

Is C-reactive protein the same as inflammation?

C-reactive protein, often shortened to CRP, is a blood marker doctors may consider alongside symptoms, examination and other tests. A single result cannot identify the cause of inflammation. ^[3] ^[7]

Do all types of omega-3 have the same role in research?

Studies use different forms and amounts. EPA and DHA are long-chain omega-3 fats found in seafood. ALA is a separate omega-3 fat found in plant foods such as walnuts and linseed, and the body converts only a small proportion to EPA and DHA. Check which form a study actually used when reading its results. ^[2]