School of Biosciences, University of Sheffield, Western Bank, Sheffield, UK.
J Gerontol A Biol Sci Med Sci. 2022 Nov 21;77(11):2181-2185. doi: 10.1093/gerona/glac100.
Dietary restriction (DR) is one of the most potent ways to extend health and life span. Key progress in understanding the mechanisms of DR, and aging more generally, was made when dietary protein, and more specifically essential amino acids (EAA), were identified as the dietary component to restrict to obtain DR's health and life-span benefits. This role of dietary amino acids has influenced work on aging mechanisms, especially in nutrient sensing, for example, Target of Rapamycin and insulin(-like) signaling networks. Experimental biology in Drosophila melanogaster has been instrumental in generating and confirming the hypothesis that EAA availability is important in aging. Here, we expand on previous work testing the involvement of EAA in DR through large-scale (N = 6 238) supplementation experiments across 4 diets and 2 genotypes in female flies. Surprisingly, we find that EAA are not essential to DR's life-span benefits. Importantly, we do identify the fecundity benefits of EAA supplementation suggesting the supplemented EAA were bioavailable. Furthermore, we find that the effects of amino acids on life span vary by diet and genetic line studied and that at our most restricted diet fecundity is constrained by other nutrients than EAA. We suggest that DR for optimal health is a concert of nutritional effects, orchestrated by genetic, dietary, and other environmental interactions. Our results question the universal importance of amino acid availability in the biology of aging and DR.
饮食限制（DR）是延长健康和寿命的最有效方法之一。当饮食中的蛋白质，更具体地说是必需氨基酸（EAA）被确定为限制以获得 DR 的健康和寿命益处的饮食成分时，对 DR 机制和衰老的理解取得了关键进展。饮食氨基酸的这种作用影响了衰老机制的研究，特别是在营养感应方面，例如雷帕霉素和胰岛素（样）信号网络。黑腹果蝇的实验生物学在产生和证实 EAA 可用性在衰老中很重要的假设方面发挥了重要作用。在这里，我们通过在 4 种饮食和 2 种基因型的雌性果蝇中进行大规模（N = 6238）补充实验，扩展了之前关于 EAA 在 DR 中作用的研究。令人惊讶的是，我们发现 EAA 对 DR 的寿命益处不是必需的。重要的是，我们确实确定了 EAA 补充对生育力的益处，表明补充的 EAA 是生物可利用的。此外，我们发现氨基酸对寿命的影响因所研究的饮食和遗传系而异，并且在我们最受限制的饮食中，生育力受到其他营养素而不是 EAA 的限制。我们认为，为了获得最佳健康，DR 是营养效应的协同作用，由遗传、饮食和其他环境相互作用协调。我们的结果质疑了氨基酸可用性在衰老和 DR 生物学中的普遍重要性。
