Limiting the number of calories you eat is a simple way to stay healthy, but its implementation couldn’t be harder, with the constant temptation of easily obtained, often fried or processed food that is so common in the Western diet. Now researchers from the University of Colorado at Boulder show how a natural dietary supplement mimics the healthy effects of calorie restriction.
A natural dietary supplement called nicotinamide riboside (NR) has the same effect on the body as calorie restriction (CR) when taken daily, researchers found. NR initiates the same chemical pathways in the body that CR does to reverse many of the physiological signs of aging; some studies have shown that CR can increase lifespan - studies with fruit flies, roundworms, rodents, and even some with humans. Past research also shows that CR promotes healthy blood pressure and arteries.
NR is a “trace component in foods” and a source of vitamin B3. Its activity includes regulating insulin sensitivity, mitochondria, and sirtuin functions. Sirtuins are enzymes research links to metabolic actions that decrease as we get older. Studies have also shown that NR has a protective effect in the brain, a finding developed in studies of Alzheimer’s disease.
In the new study, researchers recruited 24 lean and healthy men and women between the ages of 55 and 79. For the first six weeks, half were given a placebo and then given a 500 mg twice-daily dose of NR. The other half were given NR for the first six weeks and then given placebo. None of the participants reported negative side effects. Just over half (13) participants with stage 1 high blood pressure experienced lower blood pressure after supplementation with NR, potentially reducing their risk of heart attack by 25 percent.
"This was the first ever study to give this novel compound to humans over a period of time," explained senior author Doug Seals. "We found that it is well tolerated and appears to activate some of the same key biological pathways that calorie restriction does."
Seals and others also found that NR supplementation increased levels of a similar compound called nicotinamide adenine dinucleotide (NAD+) by 60 percent. NAD+ is necessary for sirtuin activation. The researchers theorized that the body “conserves NAD+ when subjected to calorie restriction.”
"The idea is that by supplementing older adults with NR, we are not only restoring something that is lost with aging (NAD+), but we could potentially be ramping up the activity of enzymes responsible for helping protect our bodies from stress,” explained lead author Chris Martens.
Going forward, Seals, Martens, and the others want to do more studies with more participants, partly to confirm the connection between NR supplementation and blood pressure reduction (and decreased heart attack risk), and partly to study other CR-mimicking compounds to be prescribed in coordination with dietary and lifestyle changes for patients at a high risk of heart disease.
The present study was published in the journal Nature Communications.
Sources: Current Opinion in Clinical Nutrition and Metabolic Care, Drug Discovery Today: Technologies, University of Colorado at Boulder