Ageing is typically associated with cardiac hypertrophy and decline of diastolic function. Eisenberg et al. report that dietary supplementation with the natural polyamine spermidine significantly extends the median lifespan of mice. Moreover, in aged mice, spermidine reversed age-associated hypertrophy and improved cardiac diastolic function through modulation of autophagy. Spermidine supplementation also lowered blood pressure and improved cardiac function in a rat model of hypertension-induced congestive heart failure. In human subjects, dietary intake of spermidine was inversely associated with high blood pressure and risk of cardiovascular disease.