A recent study published in Radiology on Apr. 17 finds that adults at risk of knee osteoarthritis who consume higher amounts of ultra-processed foods show greater fat infiltration in their thigh muscles, as measured by MRI scans.
This finding is important because muscle quality plays a key role in joint stability and mobility, especially for people prone to knee osteoarthritis. The research suggests that diet may have a direct impact on muscle health beyond its known effects on weight and metabolism.
The study analyzed data from the Osteoarthritis Initiative, including 615 participants with an average age of 59.5 years and mean body mass index (BMI) of 27. Participants completed dietary questionnaires, which revealed that about 41 percent of their daily calories came from ultra-processed foods such as those containing additives like emulsifiers and synthetic sweeteners. MRI scans were used to assess fat infiltration across different thigh muscle groups.
Results showed a linear relationship between higher intake of ultra-processed foods and increased intramuscular fat across all major thigh muscles except the extensors when adjusted for BMI; however, abdominal-circumference-adjusted models showed significant associations across all groups. Women had consistently higher levels of muscle fat than men, but sex did not alter the link between diet and muscle quality.
Researchers noted limitations including reliance on self-reported dietary data, possible misclassification due to questionnaire design, and use of semiquantitative imaging methods rather than fully quantitative ones. The authors caution that while the association is clear in this cross-sectional analysis, causality cannot be established without further longitudinal studies.
The study concludes that reducing consumption of ultra-processed foods could be a promising approach to help preserve muscle health among older adults at risk for knee osteoarthritis.
