Fibre-Enriched High-Carbohydrate (FEHC) Diet Modulates Inflammation Without Affecting Bone Health in Older Women With Obesity: A Randomised Clinical Trial

Background: In older adults, obesity is associated with frailty, conditions worsened by age related decline in bone mineral density (BMD) and muscle mass. Objective: To evaluate whether a 3-month Fibre-Enriched High Carbohydrate (FEHC) diet preserves bone health, reduces inflammation and modulates Wnt signalling in older adults with obesity. Methods: In this clinical trial, 86 women aged 65–85 years with obesity (BMI ≥ 30 kg/m2) undergoing hip arthroplasty were assigned to a free control diet (FCD) or a FEHC diet (FEHC) group for 3 months before surgery. Clinical, systemic, and molecular assessments were performed, including gene expression analyses in bone and muscle tissues. Results: A significant reduction in waist circumference was observed over time in the FEHC group (p = 0.037), whereas no changes were detected in body weight, BMD or bone microarchitecture. Compared to FCD, the FEHC group showed reduced circulating IL-6 (p = 0.03), IL-8 (p = 0.022) and TNFα (p = 0.04) levels, along with lower IL-6 gene expression in muscle (p = 0.035). A strong trend of increased IGF-1 gene expression in muscle tissue of the FEHC group was also observed (p = 0.058). Gene expression analyses revealed a significant increase in WNT5a expression in muscle (p = 0.049), and an upward trend in WNT10b expression in bone (p = 0.055) while serum levels of DKK-1 were significantly higher in the FEHC group compared to FCD (p < 0.0001). Conclusion: The FEHC diet reduces systemic and local inflammation, without affecting skeletal health in older adults with obesity.