Effects of Dietary Protein Intake on Metabolic Indicators in Postmenopausal Women: A Systematic Review and Meta-analysis

A BSTRACT This study aimed to systematically evaluate the effects of dietary protein intake on metabolic indicators in postmenopausal women, so as to provide scientific evidence for precise nutritional interventions in this population. Four electronic databases, namely PubMed, EBSCOhost, Cochrane, and Web of Science, were systematically searched. A total of 30 studies with 2028 participants were included. Meta-analysis was performed using R software to assess the effects of dietary protein intake on blood glucose, blood lipid profile (triglyceride [TG] and high-density lipoprotein [HDL]), blood pressure, and body composition (body mass index [BMI], waist circumference, and lean body mass [LBM]). Subgroup analyses were conducted according to age, intervention duration, and protein intake level. The results showed that plant protein contributed to reduced fasting glucose, TGs, HDL cholesterol, systolic blood pressure (SBP), and diastolic blood pressure (DBP), but had no significant effect on body composition. Animal protein exerted beneficial effects on reducing BMI, preserving LBM, and lowering SBP and DBP, but showed no significant regulatory effects on core glucose and lipid indicators. Subgroup analysis indicated that younger postmenopausal women were more sensitive to the metabolic effects of plant protein, while older women were more likely to benefit from body composition regulation by animal protein. This study revealed the differential regulatory effects of the two protein sources, providing evidence-based support for the development of individualized dietary protein strategies for postmenopausal women. Future studies should focus on differences in protein subtypes, mechanistic validation, and the supplementation of localized evidence in different ethnic populations.