Ultra-Processed Foods and Knee Osteoarthritis Risk
ULTRA-PROCESSED foods were linked to greater thigh muscle fat infiltration on MRI in adults at risk for knee osteoarthritis. In this cross-sectional secondary analysis, researchers assessed whether a higher proportion of ultra-processed foods in the daily diet was associated with adverse muscle changes in a population vulnerable to future joint disease.
The study used baseline data from the Osteoarthritis Initiative collected between February 2004 and October 2015. Participants were at risk for knee osteoarthritis but had no radiographic osteoarthritis, defined as Kellgren-Lawrence grade 1 or lower, and no pain in either knee or hip. The analysis included 615 participants with a mean age of 59.5 years. Of these, 340 were women. Mean body mass index was 27, and ultra-processed foods accounted for an average of 41.4% of the daily diet.
MRI Reveals Greater Muscle Fat Infiltration
Thigh muscle fat infiltration was evaluated on axial T1-weighted spin-echo MRI using Goutallier grading, from grade 0 for no fatty streaks to grade 4 for more than 50% fatty signal intensity. Standardized sum Goutallier grades were calculated for bilateral flexors, extensors, adductors, and all thigh muscles combined.
After adjustment for sociodemographic factors, calorie intake, smoking, physical activity, and depression, higher ultra-processed food intake remained associated with higher muscle fat infiltration. In body mass index adjusted models, the association was seen across all thigh muscles, bilateral flexors, and bilateral adductors. When abdominal circumference was used instead, the relationship was even stronger and extended to all major muscle groups, including extensors.
Muscle Fat Findings Were Consistent Across Sex
No statistically significant interaction was found between ultra-processed food intake and sex, indicating that the relationship was consistent in both men and women. The findings suggest that dietary quality may have measurable associations with muscle composition even before radiographic knee osteoarthritis develops.
For clinicians, the message is straightforward. In adults at risk for knee osteoarthritis, greater intake of ultra-processed foods was associated with higher muscle fat content on thigh MRI, independent of multiple lifestyle and body composition related factors. These results strengthen interest in diet as a potentially relevant factor in early musculoskeletal change.
Reference
Akkaya Z et al. Ultra-processed Foods and Muscle Fat Infiltration at Thigh MRI: Data from the Osteoarthritis Initiative. Radiology. 2026;2026;319(1).
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