“This was the first ever study to give this novel compound to humans
over a period of time,” said senior author Doug Seals, a 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 calorie
restriction does.”Dr Seal and lead author Chris Martens included 24 lean
and healthy men and women ages 55 to 79 from the Boulder area.Half were
given a placebo for six weeks, then took a 500 mg twice-daily dose of
nicotinamide riboside (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. Participants reported no serious adverse effects.
The researchers found that 1,000 mg daily of NR boosted levels of
another compound called nicotinamide adenine dinucleotide (NAD+) by 60
percent. NAD+ is required for activation of enzymes called sirtuins,
which are largely credited with the beneficial effects of calorie
restriction. It’s involved in a host of metabolic actions throughout the
body, but it tends to decline with age.
Research suggests that as an evolutionary survival mechanism, the body
conserves NAD+ when subjected to calorie restriction. But only recently
have scientists begun to explore the idea of supplementing with
so-called “NAD+-precursors” like NR to promote healthy ageing.“The idea
is that by supplementing older adults with NR, we are not only restoring
something that is lost with ageing (NAD+), but we could potentially be
ramping up the activity of enzymes responsible for helping protect our
bodies from stress,” Martens said.
The new 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 percent 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 note.
Ultimately, the authors say, 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,”
said Dr Martens, now an Assistant Professor at the University of
Delaware. “What this paper provides us with is a really good stepping
stone for future work.”
Dr Martens and Dr Seal have applied for a grant to conduct a larger
clinical trial looking specifically at the impact of NR supplementation
on blood pressure and arterial health. Dr Martens is also launching a
separate trial looking at the impact NR has on older adults with mild
cognitive impairment, a precursor to Alzheimer’s disease.
