1 Charles Perkins Centre, The University of Sydney , Camperdown, New South Wales 2006 , Australia.
2 School of Life and Environmental Sciences, The University of Sydney , Camperdown, New South Wales 2006 , Australia.
Proc Biol Sci. 2019 May 15;286(1902):20190393. doi: 10.1098/rspb.2019.0393.
Protein and calorie restrictions extend median lifespan in many organisms. However, studies suggest that among-individual variation in the age at death is also affected. Ultimately, both of these outcomes must be caused by effects of nutrition on underlying patterns of age-specific mortality (ASM). Using model life tables, we tested for effects of dietary macronutrients on ASM in mice ( Mus musculus). High concentrations of protein and fat relative to carbohydrates were associated with low life expectancy and high variation in the age at death, a result caused predominantly by high mortality prior to middle age. A lifelong diet comprising the ratio of macronutrients self-selected by mouse (in early adulthood) was associated with low mortality up until middle age, but higher late-life mortality. This pattern results in reasonably high life expectancy, but very low variation in the age at death. Our analyses also indicate that it may be possible to minimize ASM across life by altering the ratio of dietary protein to carbohydrate in the approach to old age. Mortality in early and middle life was minimized at around one-part protein to two-parts carbohydrate, whereas in later life slightly greater than equal parts protein to carbohydrate reduced mortality.
蛋白质和卡路里限制可延长许多生物的寿命中位数。然而，研究表明，个体间的死亡年龄也受到影响。最终，这些结果都必须归因于营养对特定年龄死亡率（ASM）的潜在模式的影响。使用模型生命表，我们测试了饮食中的宏量营养素对小鼠（Mus musculus）ASM 的影响。与碳水化合物相比，蛋白质和脂肪的浓度较高与预期寿命较低和死亡年龄变化较大有关，这主要是由中年前的高死亡率引起的。终生的饮食包括小鼠（在成年早期）自行选择的宏量营养素的比例与中年前的低死亡率有关，但晚年的死亡率较高。这种模式导致相当高的预期寿命，但死亡年龄的变化非常低。我们的分析还表明，通过在接近老年时改变饮食中蛋白质与碳水化合物的比例，可能可以最小化整个生命过程中的 ASM。在生命早期和中期，大约 1 份蛋白质对 2 份碳水化合物的比例可将死亡率降至最低，而在后期，蛋白质与碳水化合物的比例略大于相等则可降低死亡率。
