The Impact of Hempseed Consumption on Bone Parameters and Body Composition in Growing Mice

OBJECTIVES: This study investigated the effect of a diet containing hempseeds (HS), which are rich in polyunsaturated fatty acids and polyphenols, on body composition, bone mineral measurements and epiphyseal plate osteoblast density. METHODS: Groups (n = 8 each) of female C57BL/6 mice were fed one of three AIN-93G-based diets (15% HS by weight; 5% HS; 0% HS) from age 5 to 30 weeks. Diets contained ∼16, 18, and 60% total kcals from fat, protein and carbohydrate, respectively. In-vivo whole-body composition and bone mineral density and content were measured every 4 weeks using dual-energy x-ray absorptiometry. Ex-vivo humeri osteoblast density was determined by sectioning bone longitudinally, mounting the sections on slides and staining using alkaline phosphatase. Stain intensity at the epiphyseal plate was ranked independently by 5 evaluators. ANOVA was used to compare outcomes across groups. Linear regression was used to examine the relationship of end-point bone mineral measurements and osteoblast density. RESULTS: No differences were seen in bone mineral measurements, lean mass or fat mass across diet groups. Body weight gain did not differ across groups yet mice fed the 15% HS diet consumed significantly more food than those fed the 0% and 5% HS diets (p = 0.0002). Humeri from both HS groups displayed significantly lower osteoblast densities compared to the control group (P < 0.0001). No relationship was seen between osteoblast density and body composition measurements. CONCLUSIONS: Diets enriched with 5% and 15% HS supported growth as well as the control diet without significant impacts on whole-body composition, including bone mineral density and content. At the cellular level, however, HS consumption resulted in reduced density of osteoblasts at the epiphyseal plate. These data invite closer examination of bone cell activity and microarchitecture to determine the effect of habitual HS consumption on bone integrity. FUNDING SOURCES: Institute of Cannabis Research at Colorado State University, Pueblo; Idaho State University.