Why This Matters to Us:
For those of us passionate about longevity, understanding the safety of supplements like NMN is crucial. NMN, or nicotinamide mononucleotide, is a molecule thought to enhance lifespan and health by boosting NAD+ levels, which decline as we age. Ensuring that its use does not inadvertently harm organs like the kidneys is vital for safely incorporating it into longevity strategies.
The Detail:
A recent study by researchers at the University of Washington explored the effects of NMN on kidney health in aged mice, raising concerns about potential kidney toxicity. NMN, known for its role in boosting NAD+ and promoting longevity, appeared to increase kidney inflammation and damage when administered to the mice. The [study](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11030441/pdf/nihpp-2024.04.09.588624v2.pdf) involved giving 300 mg/kg of NMN in drinking water for 8 weeks, a dose that could translate to about 1.5 grams daily for humans—significantly higher than usual recommendations.Interestingly, a previous study showed NMN improved heart function in the same group of mice, leading researchers to expect similar benefits for the kidneys. Contrary to these expectations, the study found a spike in certain metabolites—specifically MNA, 2-PY, and 4-PY. These compounds are degradation products of NAD+, and high levels have been tied to kidney and cardiovascular issues. This was surprising since these metabolites usually marked beneficial activities in other studies.
Dr. Charles Brenner, a well-known longevity scientist, suggested an alternative explanation: contamination. He theorizes that the NMN used in the study might have been tainted with substances causing the observed kidney damage. He cites multiple animal studies where NMN and similar compounds actually protected against kidney injury, such as nicotinamide riboside (NR), which has shown promise in alleviating acute kidney issues.
Moreover, previous literature often highlights NMN’s positive impacts on kidney health. For example, studies demonstrated that NMN supplementation restored NAD+ levels and improved markers related to DNA repair in the kidneys of aged mice. NMN has also shown benefits in diabetic mice by reducing kidney scarring and enhancing survival rates.
The researchers, including Dr. Kaeberlein, acknowledge the need for cautious interpretation of these results. They emphasise that the metabolic pathways involving NAD+ might differ significantly between mice and humans, affecting NMN's impact across species. Despite NMN raising metabolites linked with certain health risks, the overarching evidence from animal studies suggests a protective role in kidney health.
However, more research is necessary to determine NMN's effects on human kidneys, especially given the complexities of NAD+ metabolism. Human studies have revealed correlations between elevated NAD+ metabolites and increased risks for cardiovascular and kidney diseases. These associations underscore the importance of carefully monitoring kidney health markers in future human trials with NMN and other NAD+ precursors.
In conclusion, while this study raises important questions about NMN and kidney health, the results may stem more from dosage or contamination complications rather than the NMN itself. For longevity enthusiasts, ensuring the purity and appropriate dosage of supplements remains key to safely leveraging their potential benefits.
