College of Health Solutions, Arizona State University, Phoenix, AZ 85004, USA.
Nutrients. 2023 Jul 16;15(14):3159. doi: 10.3390/nu15143159.
Vegan diets have gained popularity in recent years for reasons including health benefits and concerns for animal welfare. Although these diets are considered to be nutritionally adequate, questions remain over whether the current protein recommendation (0.8 g/kg/d) is sufficient. Protein status is determined through a nitrogen balance analysis when the protein content of the diet is known. A negative balance indicates a catabolic state, and a positive nitrogen balance indicates an anabolic state. In healthy adults, nitrogen equilibrium is the expectation reflecting the net synthesis and breakdown of proteins. Currently, there are no known studies measuring nitrogen balance in strict vegan men fed the protein requirement. Eighteen minimally active vegan men received a 5-day eucaloric diet (protein content: 0.8 g/kg/d). On day five, 24 h urine was collected for nitrogen analysis. Both the mean absolute nitrogen balance (-1.38 ± 1.22 g/d) and the mean relative nitrogen balance (-18.60 ± 16.96 mg/kg/d) were significantly lower than zero (equilibrium) ( < 0.001). There were no correlations seen between nitrogen balance and age, years as vegan, or fat-free mass. Consuming 0.8 g/kg/d of protein is not adequate to produce nitrogen balance in men adhering to typical strict vegan diets for at least one year.
近年来，由于健康益处和对动物福利的关注，素食饮食越来越受欢迎。虽然这些饮食被认为在营养上是足够的，但目前的蛋白质推荐量（0.8 g/kg/d）是否足够仍然存在疑问。当饮食中的蛋白质含量已知时，通过氮平衡分析来确定蛋白质状态。负平衡表示分解代谢状态，正氮平衡表示合成代谢状态。在健康成年人中，氮平衡是反映蛋白质净合成和分解的期望。目前，没有已知的研究在严格的素食男性中测量满足蛋白质需求时的氮平衡。18 名活动量最小的素食男性接受了为期 5 天的热量均衡饮食（蛋白质含量：0.8 g/kg/d）。在第 5 天，收集 24 小时尿液进行氮分析。绝对氮平衡（-1.38 ± 1.22 g/d）和相对氮平衡（-18.60 ± 16.96 mg/kg/d）的平均值均显著低于零（平衡）（<0.001）。氮平衡与年龄、成为素食者的年限或去脂体重之间没有相关性。对于至少坚持典型严格素食饮食一年的男性，摄入 0.8 g/kg/d 的蛋白质不足以产生氮平衡。
