A High-Fiber Plant-Based Diet in Myeloma Precursor Disorders - Results from the NUTRIVENTION Clinical Trial and Preclinical Vk*MYC Model.

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 (meals for 12 weeks, coaching for 24 weeks) to 23 participants 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 (n=2) or was stable. Findings were translated to Vk*MYC mice modeling the myeloma-precursor state, in which a high-fiber diet delayed disease progression through improved metabolism and microbiome composition leading to increased short-chain fatty acid production that reinvigorated anti-tumor immunity and inhibited tumor growth. These effects from fiber consumption were independent of calorie restriction and weight loss. A high-fiber diet is a low-risk intervention that may delay progression to myeloma.