A High-Fiber Plant-Based Diet Delays Progression to Myeloma in Precursor Disorders

Consumption of a western diet and high body mass index (BMI) are risk factors for progression from pre-malignant phenotypes to multiple myeloma, a hematologic cancer. In the NUTRIVENTION trial (NCT04920084), we administered a high-fiber plant-based diet to patients with myeloma precursor states and elevated BMI. The intervention was feasible, improved quality of life and modifiable risk factors: metabolic (BMI, insulin resistance), microbiome (diversity, composition), and immune (inflammation, monocyte subsets). Disease-progression trajectory improved in two participants and was stable in others. In Vk*MYC+/- mice modeling the myeloma-precursor state, a high-fiber diet delayed disease progression through improved microbiome composition and increased short-chain fatty acid production that reinvigorated anti-tumor immunity and inhibited tumor growth. These effects resulted from fiber consumption and were independent from calorie restriction-induced weight loss.