Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women

Anti-aging supplement effects in humans Synthesis of nicotinamide adenine dinucleotide (NAD + ) decreases during aging, which is thought to limit the activity of enzymes that require it for their catalytic activity. Studies in animals indicate that replenishment of cellular NAD + can have beneficial effects on aging and age-related diseases, but the situation in humans is less clear. Yoshino et al. report the effects of supplementation with the NAD + precursor nicotinamide mononucleotide in overweight or obese postmenopausal women with prediabetes (see the Perspective by Hepler and Bass). The treatment improved insulin sensitivity in muscle, although a change in NAD + content was not detected. The treatment also increased the expression of platelet-derived growth factor b. The results support potential therapeutic action of NAD + supplementation in humans, but how various NAD+ precursors are processed in specific tissues remains to be fully explored. Science , abe9985, this issue p. 1224 ; see also abj0764, p. 1147