Muscle pain is often the result of inflammation in the muscles or joints. Omega-3 polyunsaturated fatty acids help reduce inflammation and fish oils contain a high-concentration of these omega-3 PUFAs. That is perhaps why so many doctors, athletic coaches, personal trainers and nutritionists recommend fish oil to alleviate muscle and joint pain. As it turns out, fish oil may help relieve joint and muscle pain in some people but not others, and it's not yet well understood how well it works.
The omega-3 PUFAs in fish oil affect the balance of a group of compounds called prostaglandins that include both inflammation increasing and decreasing chemicals. The omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid also combat collagenase, an enzyme known to damage joints.
Much evidence has linked fish oil with relief from joint and muscle pain associated with bursitis, tendinitis, arthritis, carpal tunnel syndrome and fibromyalgia, as seen in one 2007 meta-analysis of 17 clinical trials on the analgesic benefits of omega-3 PUFAs for various inflammatory conditions. In a 2006 study reported in "Surgical Neurology," 60 percent of participants reported fish oil helped ease their back pain and 88 percent said they'd continue using fish oil for their back pain after the study concluded. Several studies, including one published in "Nutrition Research" in 2000, have shown that the omega-3 fatty acids in fish oil may also help relieve menstrual pain in women.
Exercise Pain And Soreness
Interestingly, a 2002 study published in "Medical Science And Sports Exercise" found that despite the anti-inflammatory response that helps alleviate pain from certain medical conditions, the omega-3 PUFAs in fish oil do not necessarily help relieve delayed onset muscle soreness following intense exercise. Yet a 2009 study reported in the "Clinical Journal of Sports Medicine" found just the opposite, that men with no exercise experience, after taking fish oil daily for 30 days, perceived less pain and soreness after a single 40-minute workout than men given a placebo.
Flaxseed oil actually contains more omega-3 PUFAs than fish oil. But that's mostly in the form of alphalinolenic acid, which isn't nearly as effective in reducing pain as EPA and DHA, the two omega-3 PUFAs of which fish oil has more. If you are taking any nonsteroidal anti-inflammatory dugs like aspirin and ibuprofen that thin the blood, check with your doctor before taking any omega-3 PUFA supplements as the combination can increase risk of bleeding or bruising.