Antioxidants linked to better bone health for osteoarthritis

Increased intake of fruit and the antioxidants they contain, like vitamins C and E, may improve bone health and may reduce the risk of osteoarthritis.

"Our study suggests a beneficial effect of vitamin C intake on the reduction in bone size and the number of bone marrow lesions, both which are important in the pathogenesis of knee osteoarthritis," wrote lead author Yuanyuan Wang from Monash University.

The new study, published in the Arthritis Research & Therapy, recruited 293 healthy adults (average age 58) without knee pain or injury, and asked them to complete a 121-item food frequency questionnaire (FFQ) to assess antioxidant intake.

Ten years after the start of the study the researchers measured cartilage volume, bone area, cartilage defects and bone marrow lesions using magnetic resonance imaging (MRI).

Increased intake of vitamin C was associated with a 50 per cent reduced risk of bone marrow lesions, and a smaller bone area. Fruit intake was also linked to a smaller tibial plateau bone area and a 28 per cent reduction in the risk of bone marrow lesions.

Increased intake of the carotenoids lutein and zeaxanthin was associated with a 29 per cent reduction in the risk of cartilage defects, while beta-cryptoxanthin intake was linked to smaller tibial plateau bone area.

Indeed, Wang and co-workers suggested that since vitamin C is a cofactor in the hydroxylation of lysine and proline, it could be considered a required nutrient in the cross-linking of collagen fibrils in bone.

Steve - this was a well-structured study that studied healthy subjects, not sick ones. Cross-sectional studies from food frequency questionnaires always need to be interpreted with caution. However, these researchers were looking only for antioxidants' effect on bones, nothing else. Other studies structured similarly begin with a different purpose and change directions to suit their discoveries.