Nicotinamide Riboside Nr Supplements

Nicotinamide Riboside (NR) Supplements: Efficacy, Safety, and Metabolic Impacts

Introduction to Nicotinamide Riboside (NR) Supplements

Nicotinamide riboside (NR) is a precursor to nicotinamide adenine dinucleotide (NAD+), a vital coenzyme involved in numerous metabolic processes. As a member of the vitamin B-3 family, NR has garnered attention for its potential health benefits, particularly in metabolic and age-related conditions. This article synthesizes recent research on the effects, safety, and potential therapeutic uses of NR supplements.

Safety and Metabolic Effects in Obese Individuals

Insulin Sensitivity and Glucose Metabolism

A 12-week randomized, placebo-controlled trial investigated the effects of NR supplementation (2000 mg/day) on insulin sensitivity and glucose metabolism in obese, insulin-resistant men. The study found no significant improvements in insulin sensitivity, glucose disposal, or oxidation, nor any changes in body composition or lipid metabolism. However, NR supplementation was deemed safe with no serious adverse events reported.

Body Composition and Muscle Metabolism

Another study examined the impact of 6-week NR supplementation (1000 mg/day) on metabolic health in overweight and obese individuals. While NR increased skeletal muscle NAD+ metabolites and acetylcarnitine concentrations, it did not significantly affect insulin sensitivity, mitochondrial function, or other metabolic health parameters. Minor changes in body composition, such as increased fat-free mass and sleeping metabolic rate, were observed.

Effects on Aging and Muscle Function

Muscle NAD+ Metabolome and Anti-inflammatory Effects

In aged individuals, NR supplementation (1000 mg/day for 21 days) elevated muscle NAD+ levels and reduced circulating inflammatory cytokines. However, it did not alter mitochondrial bioenergetics, suggesting that while NR can enhance the NAD+ metabolome and exhibit anti-inflammatory properties, its effects on muscle energy metabolism may be limited.

Muscle Regeneration and Physical Performance

A study on elderly individuals (55-80 years) assessed the effects of NR combined with pterostilbene (NRPT) on muscle regeneration post-injury. Despite the supplementation being safe, it did not improve muscle stem cell recruitment or other measures of muscle recovery. Conversely, another trial found that acute NR supplementation improved redox homeostasis and physical performance, specifically increasing isometric peak torque and reducing fatigue in older adults.

Long-term Effects and Mitochondrial Biogenesis

Mitochondrial Function and Gut Microbiota

A long-term study involving BMI-discordant monozygotic twins supplemented with NR (250 to 1000 mg/day for 5 months) demonstrated improvements in systemic NAD+ metabolism, muscle mitochondrial biogenesis, and gut microbiota composition. However, NR did not significantly ameliorate adiposity or overall metabolic health, indicating that while NR can enhance certain cellular functions, its broader metabolic benefits may be limited.

Sustained NAD+ Levels

A clinical trial on healthy older adults (60-80 years) showed that NRPT supplementation significantly increased NAD+ levels in a dose-dependent manner over an 8-week period. This increase was sustained throughout the trial, highlighting NRPT's potential for safely and effectively boosting NAD+ levels in humans.

Conclusion

Nicotinamide riboside (NR) supplements have shown promise in increasing NAD+ levels, enhancing muscle NAD+ metabolism, and reducing inflammation, particularly in older adults. However, their effects on insulin sensitivity, glucose metabolism, and overall metabolic health appear limited based on current evidence. While NR is generally safe and can improve certain cellular functions, further research is needed to fully understand its therapeutic potential and long-term benefits.

Summary

Not a yes or no question