Omega-3 fatty acids have already been proven to lower the triglycerides that can harden arteries and lead to heart disease, but researchers theorize these health-critical nutrients can do much more throughout the body. A new study offers intriguing evidence that fish oil supplements may ease depression symptoms, while other research found a link between low omega-3 levels and suicide. And two other recent studies show that EPA+DHA supplements may also prevent osteoarthritis and slow prostate cancer growth.
In the depression study, published in September 2011 in the British Journal of Nutrition, Australian researchers divided 50 people over the age of 65 into three groups. One group received fish oil rich in the omega-3 component EPA (eicosapentaenoic acid), one group received fish oil rich in the omega-3 component DHA (docosahexaenoic acid), and one received another essential fatty acid, omega-6. The daily dosage for the first group was 1.67 grams of EPA and 0.16 grams of DHA; the second group received 1.55 grams of DHA and 0.40 grams of EPA; and the third group took 2.2 grams of omega-6 linoleic acid per day.
After six months, both the EPA and DHA groups had improved scores on the Geriatric Depression Scale, but the results were more pronounced in the DHA group.
“These results indicate that DHA-rich and EPA-rich fish oils may be effective for depressive symptoms and health parameters,” the researchers wrote.
Research published in the Journal of Clinical Psychiatry in August 2011 found a link between DHA and suicide. U.S. scientists compared routine blood samples taken from 800 Army service members who committed suicide between 2002 and 2008, and compared them to 800 other service members. The researchers found that men with the lowest levels of DHA were 62 percent more likely to commit suicide.
“Although these data suggest that low serum DHA may be a risk factor for suicide, well-designed intervention trials are needed to evaluate causality,” researchers concluded.
British researchers tackled a different part of the body—the joints—in their animal study published in September 2011 in the journal Osteoarthritis and Cartilage. Guinea pigs were either fed a “standard Western diet” in which omega-6s outnumbered omega-3s 22 to 1, or a diet high in omega-3s (1.5 omega-6 to 1 omega-3). The omega-3s came from both fish oil and flax oil. The guinea pigs that ate the omega 3–rich diet had a 50 percent reduction in classic signs of osteoarthritis, including degradation of collagen in cartilage.
“There was strong evidence that omega-3 influences the biochemistry of [osteoarthritis] and therefore not only helps prevent disease, but also slows its progression, potentially controlling established osteoarthritis,” said leader researcher Dr. John Tarlton. “Osteoarthritis in guinea pigs is perhaps the most appropriate model for spontaneous, naturally occurring osteoarthritis, and all of the evidence supports the use of omega-3 in human disease.”
Another study, published in October 2011 in the journal Cancer Prevention Research, found that EPA+DHA supplementation also helps slow the growth of prostate cancer cells. Researchers gave 48 men who were undergoing removal of a cancerous prostate either a low-fat diet with 5 grams of fish oil a day, or a standard Western diet, for four to six weeks prior to the operation. The low-fat/fish oil diet had an omega-6/omega-3 ratio of 2 to 1, while the Western diet had a 15 to 1 ratio.
The men who took the fish oil not only had slower growth of prostate cancer cells, but also a reduction in the number of rapidly dividing cells in prostate cancer tissue, which researchers said could reduce the chances that the cancer would spread outside the prostate, where it is more difficult to treat.
Dr. Michael Murray