A study presented at the Radiological Society of North America annual meeting found that consumption of ultra-processed foods was associated with higher amounts of fat infiltration in thigh muscles, regardless of caloric intake and physical activity levels.
The cross-sectional study examined 666 participants without radiographic knee or hip osteoarthritis. Researchers showed that for each 1 standard deviation increase in ultra-processed food consumption, there was an increase of almost 1 grade in intramuscular fat content (β = 0.86, 95% confidence interval = 0.13–1.58, P = .021).
The study population included 45% men with a mean age of 59.9 years and mean body mass index (BMI) of 27.1 kg/m2. Participants consumed approximately 40% of their annual diet as ultraprocessed foods, including breakfast cereals, packaged snacks, soft drinks, frozen meals, and mass-produced baked goods.
The researchers used 3T thigh magnetic resonance imaging (MRI) to evaluate intramuscular fat through semiquantitative Goutallier grades, ranging from 0 (no fatty streaks) to 4 (> 50% fatty signal). The assessment covered bilateral flexors, extensors, and adductor muscle groups.
"This is the first imaging study investigating the relationship between MRI-based skeletal muscle quality and diet quality," emphasized lead study author Zehra Akkaya, MD, a researcher and former Fulbright Scholar at the University of California, San Francisco's Department of Radiology and Biomedical Imaging.
The study controlled for age, sex, race, BMI, total daily caloric intake, physical activity, depression, education, and income levels. The researchers found significant associations between ultraprocessed food consumption and fat infiltration in adductor and flexor muscle groups but not in extensors.
The research was part of the Osteoarthritis Initiative, a nationwide study sponsored by the National Institutes of Health. Dietary data came from the Block Brief 2000 food frequency questionnaire, with ultraprocessed food proportions calculated using the NOVA Classification system.