Table 2.
Findings from clinical studies investigating effects of NR on skeletal muscle and CV systems
| Study (Year) | Population and age | Dose | Length | Key findings related to intervention | Limitations |
|---|---|---|---|---|---|
| Dollerup et al. (2019)(36) | 40 (20: NR treated) Caucasian males, insulin-resistant, obese (58±2 years old) | 2000 mg/day | 12 weeks | No change of NAD+ metabolites in skeletal muscle; ↓ NAMPT; no change in SIRT3 levels and activity; no effect on glucose metabolism in skeletal muscle; no effect on mitochondrial abundance and activity in skeletal muscle; no effect on lipid deposition in skeletal muscle | - Small sample size - Only white male subjects - Low generalizability - No measure of physical performance |
| Elhassan et al. (2019)(35) | 12 old males (median age: 75 years old) | 1000 mg/day | 21 days | Well tolerability; no adverse events; ↑ NAD+ metabolites in skeletal muscle; ↓ expression of genes involved in energy metabolism in skeletal muscle; no effect on mitochondrial abundance and activity in muscle; no effect on hand-grip strength; no effect on forearm muscle blood flow; no effect on muscle glucose uptake and lactate production; no changes in systemic cardiometabolic parameters (blood pressure, lipid profile, fasting glucose, insulin, and HOMA-IR); ↓ circulating inflammatory markers (IL-6, IL-5, IL-2 and TNF-α) | - Small sample size - Only male subjects - No measure of physical performance at baseline |
| Dolopikou et al. (2019)(26) | 12 old males (71.5±1 years old) and 12 young males (22.9±1 years old) | 500 mg/ day | 1 day | ↑ NAD+ metabolites in erythrocytes; ↓ F2 isoprostanes in urine by 18%; ↑ isometric peak torque by 8% and fatigue index by 15% in old male | - Small sample size - Only male subjects - No measure of NAD+ metabolites in muscle - No safety data |
| Martens et al. (2018)(34) | 24 subjects, (65±7 years old) | 1000 mg/day | 6 weeks | No serious adverse effects; ↑ NAD+ metabolites in PBMCs; ↓ systolic blood pressure in individuals with elevated/stage I hypertension; no other significant change of indicators of CV health; no improvement on aerobic exercise capacity or motor function | - Small sample size - No measure of NAD+ metabolites in muscle |
| Dollerup et al. (2018)(33) | 40 (20: NR treated) Caucasian males, insulin-resistant, obese (58±1.6 years old) | 2000 mg/day | 12 weeks | No serious adverse effects; Vs. Placebo: ↑ NAD+ metabolites in urine; Vs. Baseline: no differences in body composition; not improve insulin sensitivity and other metabolic parameters |
- Small sample size - Only white male subjects - Low generalizability |
NR: nicotinamide riboside; NAD: nicotinamide adenine dinucleotide; HOMA-IR: homeostatic model assessment of insulin resistance; IL: interleukin; TNF-α: tumor necrosis factor alpha; SIRT: sirtuin; NAMPT: nicotinamide phosphoribosyltransferase; PBMCs: peripheral blood mononuclear cells