Vitamin B3 supplements may help people with peripheral artery disease walk farther, according to a Northwestern Medicine-led clinical trial published in Nature Communications.
Peripheral artery disease, or PAD, occurs when blood vessels narrow and reduce blood flow to the lower limbs, resulting in impaired muscle function and walking performance, according to the American Heart Association. The condition affects more than 12 million Americans, according to the organization’s estimates.
People with PAD often have difficulty walking far distances and there are few options for treating the condition, said Mary McDermott, MD, ’92 GME, the Jeremiah Stamler Professor of Medicine in the Division of General Internal Medicine, who was first and corresponding author of the study.
In the study, McDermott and her collaborators sought to test the effectiveness of a form of vitamin B3, called nicotinamide riboside, in people with PAD. Nicotinamide riboside is a precursor to NAD+, a coenzyme essential for creating energy and for normal cellular metabolism, McDermott said.
“People with lower extremity peripheral artery disease have mitochondrial activity impairment and other metabolic problems that are likely to be improved by increasing NAD+,” said McDermott, who is also a professor of Preventive Medicine in the Division of Epidemiology. “Nicotinamide riboside is available over the counter. However, despite animal data showing benefits of vitamin B3 on mitochondrial activity and skeletal muscle health and function, nicotinamide riboside had not been previously shown to improve walking performance in humans, to our knowledge.”
The clinical trial included 90 people with PAD who were asked to walk as far as they could in 6 minutes during baseline testing. After taking either nicotinamide riboside alone or in combination with resveratrol or placebo for 6 months, the participants completed another timed walk.
Those that took nicotinamide riboside alone increased their 6-minute walk distance by 17 meters, compared to placebo, according to the study.
“When we focused on people who took at least 75 percent of their nicotinamide riboside, the benefits were greater – an approximately 30-meter improvement in walking distance, compared to placebo,” McDermott said. “These results are significant because few therapies have been identified to improve walking impairment in people with peripheral artery disease.”
The results are comparable to other interventions studied by McDermott, including supervised exercise training, she said.
“The fact that the benefits were comparable to supervised exercise in adherent patients suggests a large meaningful effect,” McDermott said.
Next, McDermott and her collaborators plan to conduct a larger, multi-center clinical trial to validate their results, she said.
“We are encouraged by the positive findings,” McDermott said. “In healthier human populations, NR did not show beneficial effect on 6-minute walk. It may be that because patients with PAD have severe pathologic changes in their skeletal muscles, damaged mitochondria, increased oxidative stress, and skeletal muscle damage, they are more susceptible to benefits of nicotinamide riboside.”
Feinberg co-authors of the study include Clara Peek, PhD, assistant professor of Biochemistry and Molecular Genetics and Medicine in the Division of Endocrinology; Pei Zhu, PhD, research assistant professor of Biochemistry and Molecular Genetics; Philip Greenland, MD, the Harry W. Dingman Professor of Cardiology; Karen Ho, MD, the John Marquardt Clinical Research Professor of Vascular Surgery; Robert Sufit, MD, professor in the Ken and Ruth Davee Department of Neurology Division of Neuromuscular Disease and of Surgery in the Division of Organ Transplantation; Lihui Zhao, PhD, associate professor of Preventive Medicine in the Division of Biostatistics; and Kathryn Domanchuk, clinical research associate in the McDermott laboratory.
The study was supported by the American Heart Association.