New findings from investigators at the University of Colorado Boulder indicate that when people consume a natural dietary supplement and precursor to vitamin B3 called nicotinamide riboside (NR) daily, NR mimics caloric restriction (CR) and kick-starts the same key chemical pathways responsible for its health benefits. Findings from the new study were released today in Nature Communications, in an article entitled “Chronic Nicotinamide Riboside Supplementation Is Well-Tolerated and Elevates NAD+ in Healthy Middle-Aged and Older Adults.”
Researchers have long been aware that restricting calories can stave off the physiological signs of aging, with studies from fruit flies, roundworms, rodents, and even humans showing that chronically slashing intake by about a third can reap a myriad of health benefits and, in some cases, even extend lifespan. However, from a public health perspective, this approach could be impractical for many and potentially dangerous for others.
Amazingly, in this new study, the research team found that the readily available dietary supplement NR improves blood pressure and arterial health, particularly in those with mild hypertension.
“This was the first ever study to give this novel compound to humans over a period of time,” explained senior study investigator Doug Seals, Ph.D., professor, and researcher in the department of integrative physiology at the University of Colorado Boulder. “We found that it is well tolerated and appears to activate some of the same key biological pathways that CR does.”
The current study included 24 lean and healthy men and women ages 55 to 79 from the Boulder area. Half of the participants were given a placebo for six weeks, and then took a 500-mg twice-daily dose of NR chloride (NIAGEN). The other half took NR for the first six weeks, followed by placebo. The researchers took blood samples and other physiological measurements at the end of each treatment period.
Interestingly, the CU Boulder team found that 1000 mg daily of NR boosted levels of another compound called nicotinamide adenine dinucleotide (NAD+) by 60%. NAD+ is required for activation of enzymes called sirtuins, which are largely credited with the beneficial effects of CR. They are involved in a host of metabolic actions throughout the body, but they tend to decline with age.
The scientists hypothesized that as an evolutionary survival mechanism, the body conserves NAD+ when subjected to CR. But only recently have researchers begun to explore the idea of supplementing with so-called “NAD+ precursors” like NR to promote healthy aging.
“The idea is that by supplementing older adults with NR, we are not only restoring something that is lost with aging (NAD+), but we also could potentially be ramping up the activity of enzymes responsible for helping protect our bodies from stress,” noted lead study investigator Chris Martens, Ph.D., who is currently an assistant professor at the University of Delaware.
The current study also found that in 13 participants with elevated blood pressure or stage 1 hypertension (120–139/80–89 mmHg), systolic blood pressure was about 10 points lower after supplementation. A drop of that magnitude could translate to a 25% reduction in heart attack risk.
“If this magnitude of systolic blood pressure reduction with NR supplementation is confirmed in a larger clinical trial, such an effect could have broad biomedical implications,” the authors wrote.
Ultimately, such CR-mimicking compounds could provide an additional option—alongside the dietary changes and exercise currently recommended—for people whose blood pressure is not yet high enough to warrant medication but who are still at risk for a heart attack.
“We are not able to make any definitive claims that this compound is safe or going to be effective for specific segments of the population,” Dr. Martens stressed. “What this paper provides us with is a really good stepping stone for future work.”