Benefits and limitations of nicotinamide riboside (No.) in humans

Nicotinamide riboside (NR) is a promising dietary supplement that may have beneficial effects on human health by increasing nicotinamide adenine dinucleotide (NAD+) levels. However, despite promising preclinical results, human clinical trials have yielded mixed results. In this article, we will review the clinical studies on NR supplementation to date and discuss both the benefits and limitations of its use.

Review of Clinical Trials on NR

Over the past few years, a number of clinical trials have been conducted to assess the efficacy and safety of nicotinamide riboside (NR) supplementation in humans. These studies included diverse populations, including healthy individuals, obese individuals, elderly individuals, and individuals with various medical conditions, such as metabolic diseases, heart failure, and neurodegenerative diseases.

Most clinical studies have focused on assessing whether NR supplementation increases NAD+ levels in the body and what its metabolic and health effects are. For example, studies in healthy volunteers have shown that NR supplementation increases NAD+ and related metabolites in the blood, suggesting that NR is efficiently converted and absorbed by the body.

Results and Benefits of NR Supplementation

Increased levels of NAD+ and its metabolites

Most clinical studies have shown that NR supplementation leads to increased levels of NAD+ and its metabolites, such as nicotinamide adenine dinucleotide (NAAD) and methylnicotinamide (MeNAM), in peripheral blood. This is important because NAD+ plays a key role in energy metabolism and can support mitochondrial function and DNA repair processes, which is particularly important in the context of aging and age-related diseases.

Reduction of inflammation

Several studies indicate that NR may reduce inflammation in the body. For example, studies in people with heart failure showed that NR supplementation reduced levels of some inflammatory markers, such as interleukin-6 (IL-6) and IL-18, in peripheral blood. Reducing inflammation may contribute to improved overall health and reduced risk of chronic diseases, such as cardiovascular disease and diabetes.

Potential benefits in neurodegenerative and metabolic diseases

Studies suggest that NR may have beneficial effects on neurodegenerative diseases such as Parkinson's disease and amyotrophic lateral sclerosis (ALS). In clinical trials in Parkinson's patients, NR supplementation has been shown to increase NAD+ levels in the brain and improve some cognitive functions. Improved motor function has also been observed in ALS after NR supplementation, suggesting that NR may have potential therapeutic applications in neurodegenerative diseases.

Clinical Trial Limitations and Challenges

Small sample size and population heterogeneity

Most clinical trials of NR have had relatively small sample sizes, which may affect their reliability and generalizability. Additionally, population heterogeneity (including age, gender, health status, and lifestyle) may lead to different responses to supplementation, making it difficult to clearly determine the benefits and risks of NR.

Lack of standard research protocols

There is a wide variability in the doses of NR used, the duration of supplementation, and the methods of assessing the effects, making it difficult to compare the results of different studies. Different research protocols and lack of standardization may lead to discrepancies in the results, which in turn requires more rigorous studies in the future.

Limited long-term safety data

Although clinical studies show that NR is generally safe and well-tolerated, there is little data on the long-term safety of NR supplementation. Further research is needed to understand the long-term effects of NR, particularly in the context of its effects on metabolism, mitochondrial health, and aging.

The results of some studies are contradictory

While some studies indicate health benefits of NR, others show minimal or no clinical effects. For example, studies examining the effects of NR on insulin sensitivity and blood glucose levels have been inconclusive, suggesting that the effects of NR may be dependent on the clinical context and specific study conditions.

Future Perspectives and Research Needs

Increasing sample size and standardizing protocols

To obtain more reliable and consistent results, future studies should include larger groups of participants and use standardized research protocols that will allow for better comparison of results and drawing more clear conclusions.

Long-term safety research

Further research on the long-term safety of NR supplementation is needed to understand its potential side effects and risks associated with long-term use. It is particularly important to focus on populations with various medical conditions and older adults who may benefit most from NR supplementation.

Research on the mechanisms of action of NR

Further research should focus on better understanding the mechanisms by which NR affects health, including its effects on energy metabolism, mitochondrial function, and DNA repair processes. A better understanding of these mechanisms may help optimize the use of NR in various clinical contexts.

Summary

Nicotinamide riboside (NR) is a dietary supplement with promising health properties that can raise NAD+ levels and support metabolic health. Although results from human clinical trials are mixed, there is evidence that NR can reduce inflammation and support mitochondrial health. However, further, more rigorous clinical trials with larger groups of participants, standardized protocols, and longer follow-up are needed to fully evaluate its benefits and limitations.

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The text was developed using the support of OpenAI artificial intelligence (ChatGPT), based on an extensive review of scientific research and available sources in medical and popular science literature.