Australian researchers have found that a diet high in saturated fat is a prime suspect in the onset of osteoarthritis after finding that it changes the composition of cartilage, especially in the weight-bearing joints of the hip and knee.

"Our findings suggest that it's not wear and tear but diet that has a lot to do with the onset of osteoarthritis," said lead researcher Professor Yin Xiao.

In possibly the first study to investigate the link between osteoarthritis and common dietary fatty acids, scientists at the Queensland University of Technology studied the effects of diets rich in a variety of fatty acids, found in butter, coconut oil, palm oil, and animal fat, and simple carbohydrates. Simple carbs found in sugar, corn syrup, and high-fructose corn syrup and the combination of high-fat, high-carb foods are commonly known as "junk food."

"The main function of cartilage is to seal the bone ends in a joint and absorb pressure on the bones during weight-bearing movement such as walking," said Xiao.

"We found that a diet containing simple carbohydrates together with 20 percent saturated fats produced osteoarthritic-like changes in the knee.

"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.

"We also found changes in the bone under the cartilage on a diet rich in saturated fat."

But when the team tested lauric acid, a saturated fatty acid found in coconut oil, their findings were different. "Interestingly, when we replaced the meat fat in the diet with lauric acid we found decreased signs of cartilage deterioration and metabolic syndrome so it seems to have a protective effect," said researcher Sunder Sekar.

He said fatty acids could cause tissue inflammation throughout the entire joint. "We tested a variety of saturated fats and found that long term use of animal fat, butter, and palm oil could weaken the cartilage.

"Replacement of traditional diets containing coconut-derived lauric acid with palm oil-derived palmitic acid or animal fat-derived stearic acid has the potential to worsen the development of both metabolic syndrome and osteoarthritis," Sekar said.

Other studies have found that coconut oil benefits the body in many ways, including reducing the deep abdominal fat that's a risk for heart disease, and reducing the buildup of proteins in the brain associated with Alzheimer's.