Swapping roast potatoes and white toast for low-GI (glycemic index) wholemeal rice and bread is an all-too-familiar pattern across the world as those at risk of developing diabetes try every diet going to keep high blood glucose at bay. A remarkable new study released in April 2021 has shown there could be a much easier way to prevent diabetes developing though – and NMN is right at the heart of it.
The fascinating new study, published in Science, drilled down into the effects supplementing with NMN for 10-weeks had on post-menopausal women who had all been identified as overweight and prediabetic. Remarkably, even at a low dose of just 250mg NMN, muscle insulin sensitivity for those women was shown to be an average of 25% higher. The huge significance of this is a decline in insulin sensitivity is one of the key causes of type 2 diabetes, so the results indicate NMN could play a vital role in combatting the condition understood to be the seventh leading cause of death in the United States alone.
Scientists were optimistic the human study would produce promising results for female participants as previous studies with mice have already shown how effective NMN was in increasing muscle insulin sensitivity for female mice. The review explains, “We specifically studied post-menopausal women because NMN treatment caused greater beneficial metabolic effects in female than male mice with diet-induced diabetes.” Just how remarkable these latest results are could not have been predicted though.
The Key Findings
Several parameters were evaluated in this study, such as “body composition (fat mass, fat-free mass, intra-abdominal adipose tissue volume, and intrahepatic triglyceride content), blood pressure, plasma glucose, insulin, free fatty acid, lipids, adiponectin and leptin concentrations, and both basal glucose and fatty acid kinetics, that did not change in either group after 10 weeks of treatment.” So, what are the significant findings from this study?
First and foremost, it was interesting to get evidence of NMN supplementation boosting the plasma concentration of NMN metabolites N-methyl-2-pyridone-5-carbox-amide and N-methyl-4-pyridone-5-carboxamide. Moreover, after 10 weeks of treatment, the muscle content of NAD+ and nicotinamide did not change, but the level of NAD+ intermediates N-methyl-nicotinamide, me-thyl-2-pyridone-5-carboxamide, and N-methyl-4-pyridone-5-carboxamide increased significantly, suggesting NMN managed to increase the overall NAD+ turnover in muscle tissue. These 2 findings are important as they indicate the oral bioavailability of NMN and the fact that it does indeed affect NAD+ levels.
In addition, the study found an “increase in muscle insulin signaling (increased insulin-stimulated phosphorylated AKT and mTOR) and muscle insulin sensitivity (increased insulin-stimulated glucose disposal rate expressed per kg fat-free mass) in postmenopausal women with prediabetes who are overweight or obese. This improvement in muscle insulin sensitivity is clinically relevant and is similar to the improvement observed after ~10% weight loss...”
The Take Home Message
This human study was a “randomized, placebo-controlled, double-blind trial” to ensure the effect of NMN supplementation was evaluated as effectively as possible. However, the 250mg NMN the 24 women took daily is a small dosage compared to the amounts of NMN our fury, rodent friends are usually administered during mouse studies. Dr David Sinclair, a Harvard Geneticist looked to for his expertise in the ageing field, openly said he takes 1g of NMN daily, and many longevity enthusiasts take at least 500mg-1g of NMN per day. There are now calls for more studies to demonstrate the benefits of using higher doses of NMN.
As many animal studies have already shown NMN supplementation not only boosts the levels of an essential coenzyme called NAD+ but also reverses the signs of ageing, NMN has subsequently become one of the bestselling supplements on the anti-ageing market. This unveiling of its power to increase muscle insulin sensitivity as well will no doubt add to the supplements growing popularity. What’s more, the study also points to evidence the women experienced increased autophagy and collagen production as well – two additional tools to fight the ageing process.
Further good news from the study is there were no adverse events reported whatsoever from the trial – indicating just how safe NMN, also found naturally in foods such as avocado and broccoli, is to take. As Diabetes UK website reveals, one in ten people over 40 in the UK are now living with a diagnosis of type 2 diabetes – and it is predicted by 2030 this number will rise to 5.5 million. With this latest study showing how safe and effective NMN can be in improving insulin muscle sensitivity, it may not be long before GPs are handing out NMN as the most effective way to curb the rise in patients with diabetes – and to curb the rise in those blood glucose levels.
- Nicotinamide mononucleotide increases muscle insulin sensitivity in prediabetic women https://science.sciencemag.org/content/372/6547/1224