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Do Omega 3 + Fish Oil Reduce Inflammation for Arthritis and Joint Pain?

There is a lot of excitement surrounding omega 3 fatty acids as well as fish oil supplements in benefiting our overall health. But do omega 3 fatty acids or fish oil supplements help reduce inflammation when it comes to arthritis and joint pain? I’m going to review some clinical trials to help you decide if these common supplements are worth taking for your joint pain.

Omega 3 fatty acids are essential fats that are involved in a number of important processes in the body, including the regulation of inflammation. They are found in a variety of foods, including fatty fish, flaxseeds, and walnuts, and are also available in supplement form, typically as fish oil supplements.

There are actually three types of omega 3 fatty acids: EPA, DHA, and ALA. The first two, EPA and DHA, are found in fatty fish and fish oil supplements. The third, ALA, is found in plant based sources such as nuts and olive oil. More research has focused on marine omega 3 fatty acids as they seem to have a more potent effect on the body.

For example, a very recent study in the British medical journal found that higher seafood derived omega 3 fatty acids were associated with lower risk of chronic kidney disease, but this was not true of omega 3’s derived from plant sources.

Omega 3 fatty acids work by inhibiting the production of pro-inflammatory chemicals called prostaglandins and leukotrienes. These often contribute to pain related to symptomatic osteoarthritis. By reducing the production of these signaling molecules, omega 3 fatty acids may help alleviate joint pain and reduce swelling in those who suffer from arthritis. That’s at least in theory, but now let’s see what the clinical trials say.

This randomized controlled trial looked to examine the effects of omega 3 fatty acids in patients with knee osteoarthritis. They randomized 202 patients to a high dose 4.5 grams of omega 3 fatty acids or to a low dose 0.45 grams of omega 3 fatty acids. They assessed WOMAC outcome scores at 3 months, 6 months, 1 year, and 2 years out. They also assessed knee cartilage volume at 2 years follow up.

The authors report that both groups showed improvements in symptoms at all follow up time periods. However, they found that the low dose group had better improvements in symptom scores when compared to the high dose. There were no differences in cartilage volume at the final 2 year time point. The big limitation to this study is that there was no placebo control group included in the trial.

The next randomized controlled trial included 235 patients all with mild to moderate knee osteoarthritis. Participants were randomized to krill oil or placebo. The krill oil included 0.6 grams of EPA per day, 0.28 grams of DHA per day, and 0.45 grams of astaxanthin per day. WOMAC outcome scores were assessed at 3 months and at 6 months.

The authors found that the knee pain score improved in both groups with greater improvements for krill oil than for placebo, with a difference of 5.18. They also write that knee stiffness and physical function also had greater improvements with krill oil than with placebo, with a difference of 6.45.

The authors conclude that “Krill oil was safe to consume and resulted in modest improvements in knee pain, stiffness, and physical function in adults with mild to moderate knee osteoarthritis.” Now some clinicians, myself included, would argue that a WOMAC score difference of between 5 and 7 is relatively small and may not be clinically meaningful or have much effect on quality of life on a day to day basis.

The last study I want to review is from November of 2020. This was a randomized controlled trial that compared vitamin D to omega 3 fatty acids for the prevention of cancer and cardiovascular disease. The authors took a subgroup of patients within this trial that reported they had chronic knee pain. They analyzed a total of 1398 participants to see if omega 3 fatty acids or vitamin D helped improve their knee pain over the course of 5 years.

The authors conclude that “our findings indicate that vitamin D and omega 3 fatty acid supplementation does not reduce knee pain or improve function or stiffness in a large sample of US adults with chronic knee pain.”

The limitation of this study is that all patients with chronic knee pain were included, not just knee arthritis. Other common causes of persistent knee pain are patellofemoral pain syndrome, iliotibial band syndrome, and patellar tendinopathy. These are actually more related to biochemical issues and repetitive stress injuries rather than an underlying inflammatory disorder.

So one counter argument would be, well if you included all causes of chronic knee pain, then it would make sense that taking omega 3 supplements wouldn’t help. The rebuttal to this would be that the average age included in the study was almost 68 years old. And that people who have persistent knee pain at 68 years old almost certainly have some form of underlying knee arthritis.

Ok so what are my thoughts on all of this and what do I recommend for my patients? I think the first thing to point out is that there is a lack of high quality randomized controlled trials specifically looking at the use of omega 3 fatty acids for the treatment of symptomatic knee osteoarthritis. From the little data we have, the evidence is mixed. Some show no benefit, while others show statistically significant benefit, but with a small clinical effect.

And what about the safety profile? Fish oil and omega 3 supplements are generally considered safe. There are some concerns over bleeding time and platelet function. High doses of EPA can increase bleeding time, but this has not been associated with higher rates of clinical bleeding. The VITAL trial had a large sample size and it showed no evidence that increased intake of omega 3 fatty acids caused changes to a risk for bleeding. Then there’s the question of platelet function. Laboratory studies have shown that omega 3 fatty acids suppress platelet activating factors. However, in human clinical trials, these effects are not reliably seen.

So do I recommend taking fish oil? Well, if the question is specifically for joint pain and arthritis, then the answer is no. I think there is insufficient evidence right now to show that taking omega 3 fatty acid supplements will help decrease symptoms related to arthritis. However, that does not mean it can’t help with other aspects of your health including cardiovascular disease as well as kidney disease.

In addition, I think it’s important to point out that supplementing more omega 3 may not help, but incorporating foods that contain high amounts of omega 3 likely will help. These include fish and nuts. Both of these are important foods and are found as part of an anti-inflammatory diet. In general, it’s wise to avoid foods that contain high amounts of omega 6 fatty acids. Examples of these include fried foods, fatty foods, and processed foods. Animal studies have shown that a diet with more omega 6 than omega 3 is correlated with worse osteoarthritis severity and worse synovitis.


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