Osteoarthritis pinned on saturated fats and carbs

A diet high in fat and carbohydrates can induce osteoarthritis, a study has found, contradicting the standard position that the crippling condition is caused by mechanical deterioration.

Research led by Yin Xiao of the Queensland University of Technology and Lindsay Brown at the University of Southern Queensland found that a diet high in saturated fats weakened the composition of cartilage, particularly in weight-bearing joints such as the knee.

The effects of high-fat diets on joint structure has been little studied until now, and Xiao and Brown’s rat-based research seems set to ignite new debate around food intake and health.

The scientists tested the effects of common ingredients including butter, coconut oil, palm oil and animal fat, combined with simple carbs – a mix that mimics many types of junk food.

They found that a carb-based diet containing 20% saturated fats produced significant changes in the rats’ load-bearing cartilages – characterised as  “degeneration”, “irregularity” and “disorganisation” – resulting in osteoarthritis.

“Our findings suggest that it’s not wear and tear but diet that has a lot to do with the onset of osteoarthritis,” says Xiao.

“Saturated fatty acid deposits in the cartilage change its metabolism and weaken the cartilage, making it more prone to damage. This would, in turn, lead to osteoarthritic pain from the loss of the cushioning effect of cartilage.”

The damaging results were consistent for animal fat, butter and palm oil. Perhaps significantly, lauric acid, found in coconut oil, did not produce cartilage damage and might even have a protective effect.

The study, published in the journal Scientific Reports, calls for human clinical trials to assess whether replacing palm oil with lauric oil in commercial food might reduce the incidence of osteoarthritis.