The virtues of consuming omega 3 fatty acids have been well documented. Now scientists believe they have discovered that it may also help in getting healthier joints, as exhibited in mice who had osteoarthritis. The study by Duke University suggests that along with obesity, unhealthy dietary fats may also contribute to worsening osteoarthritis.The research was published in in the Annals of the Rheumatic Diseases on July 11.

"Our results suggest that dietary factors play a more significant role than mechanical factors in the link between obesity and osteoarthritis," said Farshid Guilak, Ph.D., Laszlo Ormandy Professor of Orthopaedic Surgery at Duke and the study's senior author in a press release.

Osteoarthritis (OA) is a painful disease of the joints affecting nearly one in two Americans. Around 27 million adults have been estimated as suffering from OA currently. Also called wear-and-tear arthritis, it occurs when the cartilage that covers the bone starts wearing down. It develops slowly and worsens over time. The most common symptoms are pain, tenderness, and stiffness in the affected joints after continuous use or a long period of inactivity.

While the risk of OA increases with age, other factors like injury to the joint, or congenital bone deformities are thought to be responsible. Obesity is also considered to be a primary cause though how exactly it contributes to OA is not known. Some believe, that carrying all that extra weight puts added pressure on joints such as knees, but this does not explain why OA affects hands and other joints that don't bear weight.

In the current study the researchers tried to examine factors other than obesity that may contribute to OA. In an earlier study, the lack of appetite hormone leptin in obese mice was found to contribute to their arthritis."This made us think that maybe it's not how much weight you gain, but what you eat," Guilak said. To find this researchers worked with mice with osteoarthritis of the knee caused by injury to the joint. Arthritis resulting from trauma or injury is thought to account for 10 to 15 percent of all cases of arthritis.

The mice were fed on diets that were either rich in saturated fats, or in omega 6 fatty acids, or a diet rich in omega 6 fatty acids but supplemented with a small amount of omega 3 fatty acids. Saturated fats which occur naturally in many food like meat and dairy products, increase cholesterol levels in blood. Omega 6 fatty acids are essential fatty acids and are needed for growth and development and normal brain function. They are found in corn oil, soybean oil, nuts and seeds. Omega 3 fatty acids, the healthiest of all, are found in fish such as salmon, tuna, sea algae, and also some nuts.A healthy diet has a balance between omega 6 and omega 3 fatty acids and Mediterranean diets as such are considered to have an optimal balance between these two.

American diets, unfortunately, do not meet this balance and are higher in saturated fats and omega 6 fatty acids than in omega 3.

In the experiment the researchers found that the mice’s diet rather than their weight more profoundly affected their arthritis. Mice that ate diets high in saturated fat or omega 6 fatty acids experienced significant worsening of their arthritis, while mice consuming a small supplement of omega 3 fatty acids had healthier joints. "While omega 3 fatty acids aren't reversing the injury, they appear to slow the progression of arthritis in this group of mice," Guilak said. "In fact, omega 3 fatty acids eliminated the detrimental effects of obesity in obese mice."

The study also confirmed the potential role of omega 3 fatty acids in wound healing, when wounds caused by a small ear punch in the mice given supplements healed more rapidly than in those who did not receive it. "We found that independent of body weight, dietary fatty acids regulate ear wound healing and severity of osteoarthritis following joint injury in obese mice," said Chia-Lung Wu, a biomedical engineering graduate student in the Duke Orthopaedic Research Laboratories and the study's lead author. The researchers hope to replicate these results on humans next.

"A great next step would be to do a clinical study to look at effect of omega 3 fatty acids post-injury," Guilak said.

Source-Guilak F, Wu C, Jain D, et. al, Annals of the Rheumatic Diseases,2014.