8353 Impact of a plant-based protein diet on bone health and body composition in Sprague Dawley rats
Authors: Gomes M M , de Araújo I M , Rodriguez S V , Jorge F R , de Paula F J 
Published: October 2024

Abstract
Disclosure: M.M. Gomes: None. I.M. de Araújo: None. S.V. Rodriguez: None. F.R. Jorge: None. F.J. de Paula: None.
Introduction:Vegetarian and vegan diets are associated with some health benefits; this has contributed to their growing popularity. Although studies remain limited, there is evidence that these patients may be at greater risk of reduced bone mineral density (BMD) and increased fracture risk. The general objective of this study was to analyze the impact of a high-protein, plant-based diet on bone tissue and body composition in male Sprague Dawley rats. Methodology: The study was approved by the Animal Ethics Committee. This study was done with 10 rats in the control group (CG), which received a standard AIN-93M diet; 11 in the normoprotein vegetarian group (NVG), with a normoprotein AIN-93 diet modified with pea protein and methionine; and 11 in the high-protein vegetarian group (HVG), with a modified AIN-93 diet with 40% pea protein and methionine. The dietary intervention lasted 8 weeks. The weight of the animals was measured weekly. Basal blood glucose levels were measured at baseline. At the end of the study, 6 rats from the CG, 6 rats from the NVG, and 5 rats from the HVG were subjected to a glucose tolerance test (GTT). The dual-energy X-ray absorptiometry (DXA) technique was applied in the baseline and final periods of the experiment to evaluate body composition, bone mineral content (BMC) and BMD. After sacrifice, bone strength was measured via a three-point flexion mechanical test on the tibia; brown adipose, epididymal, and retroperitoneal tissues, as well as the liver, were weighed on an analytical balance. Blood was used to measure circulatory levels of insulin, CTX, and P1NP (n=6/group). Results: Basal weight was similar between the groups, but the final weight was lower in the HVG as compared to the CG. In the DXA evaluation, the final lean mass was not different between the groups. On the other hand, total fat mass was lower in the HVG than in the CG and the NVG and the fat percentage was lower in the HVG than in the CG. The weight of epididymal adipose tissue was lower in the HVG than in the NVG, but retroperitoneal and brown adipose tissues were lower in HVG than CG. Liver weight was similar between groups. BMD was similar between groups; however, BMC was lower in the HVG than in the CG and the NVG. Bone strength was similar between groups. There was no difference in glycemia at baseline or during GTT at the eighth week. Serum levels of insulin, CTX, and P1NP were similar between groups. Discussion and Conclusion: A normoprotein vegetarian diet that includes all essential amino acids appears to have no negative impact on body composition or BMD in rats. On the other hand, a high-protein diet with plant protein appears to have a negative impact on bone mineral content, in addition to reducing the amount of body fat and weight. This finding expands on previous results by showing that high-protein diets have a negative impact on bone even when the protein is of plant origin.
Presentation: 6/1/2024