This theory has not aged well.
In a new study, a popular supplement commonly marketed to improve longevity failed to show significant benefits for people with early-stage Parkinson’s disease.
The results dash hopes that the vitamin B3 derivative could slow the progression of the disease – with symptoms even worsening in some patients.
Parkinson’s disease develops when nerve cells in the brain become damaged and die, reducing levels of dopamine, a chemical messenger that helps coordinate movements.
As the disease progresses, patients may develop tremors, muscle stiffness, slowed movements, and balance problems.
It can also cause non-motor symptoms, including depression, anxiety, sleep problems, digestive problems, speech changes, bladder problems, and sudden drops in blood pressure when standing.
The study authors recruited 410 adults aged 35 and older from 11 centers across Norway who had been diagnosed with early-stage Parkinson’s disease in the previous two years.
Before the trial, all took levodopa with carbidopa or benserazide three times a day, plus 10 milligrams of selegiline daily. They remained on their usual medications throughout the study unless clinically necessary.
At first, the researchers rated each of the participants using the MDS-UPDRS scale, a standard measure of Parkinson’s disease severity. The more severe the symptoms, the higher the score.
Participants were then randomly divided into two groups. One took a 500-milligram tablet of nicotinamide riboside (NR) twice daily for a year, while the other received a placebo.
NR is a form of vitamin B3 that the body converts to nicotinamide adenine dinucleotide, or NAD+.
NAD+ plays a role in several essential processes, including converting food into energy, repairing damaged DNA, maintaining cellular defenses, and regulating the body’s internal clock.
NAD+ levels naturally decline as people age, and changes in the molecule have been linked to aging and several chronic diseases, including heart disease, Alzheimer’s disease, and vision loss.
NR has become a $2 billion global market, as celebrities from Kendall Jenner to Joe Rogan and Jennifer Aniston have touted the benefits of NAD+.
Previous laboratory studies and small clinical trials had raised hopes that increased NAD+ levels could protect nerve cells damaged by Parkinson’s disease.
But when researchers put this theory to a broader test, the results fell short.
After one year, participants taking NR saw their scores deteriorate by an average of 2.45 points on the MDS-UPDRS scale. In the placebo group, scores improved by 0.27 points.
The difference of 2.72 points between the groups was statistically significant and favored the placebo, but it was too small to be considered clinically significant, the study authors note.
The team also assessed non-motor symptoms, including mood and sleep problems, which were worse in those taking NR than in those given the placebo.
Imaging tests showed no evidence that NR slowed or speeded up changes in the brain’s dopamine system. The overall adverse event rate was also similar in both groups.
“NR clearly increased NAD metabolism, but this did not translate into clinical improvement,” Charalampos Tzoulis, study leader and professor at Haukeland University Hospital and the University of Bergen, said in a press release. “Our results therefore do not support NR as a treatment to slow Parkinson’s disease.”
Based on these results, researchers recommended against the use of NR or other NAD-boosting products to treat Parkinson’s disease outside of controlled clinical trials.
However, they noted that the results do not rule out the possibility that treatments targeting NAD+ could help fight other diseases.
“Even though the results were not what we hoped for, their contribution answered an important medical question and provided valuable directions for future research,” Tzoulis said.
These findings mark the latest development in the ongoing search for better treatments for Parkinson’s disease, a disease that affects more than 10 million people worldwide, including about 1.1 million in the United States, according to the Parkinson Foundation.
Each year, approximately 90,000 Americans are diagnosed with the progressive disorder, which is more common in men and older adults.
The exact cause remains a mystery to most patients, although researchers believe a combination of genetic, environmental and aging factors play a role.
There is currently no cure for Parkinson’s disease, but medications, supportive therapies and procedures such as deep brain stimulation can help manage symptoms and improve quality of life.
Gn Health
