Low levels of vitamin B12 in patients in the early stages of Parkinson’s disease are linked to faster motor and cognitive decline, suggesting that vitamin supplements may help slow the progression of these symptoms, a study has found.
The study, “Vitamin B12 and homocysteine levels predict different outcomes in early Parkinson’s disease,” was published in the journal Movement Disorders.
Several previous studies have shown that B12 deficiencies are common in Parkinson’s patients. Deficiency of this vitamin promotes development of neurological and motor symptoms associated with the disease, including depression, paranoia, muscular numbness, and weakness.
While most studies have addressed the association of B12 with more advanced Parkinson’s disease, little is known about its contribution in the early stages of the disease before treatment begins.
University of California San Francisco (UCSF) researchers analyzed B12 levels in 680 patients recently diagnosed with Parkinson’s who had not begun treatment. The participants were followed for two years, during which physical and cognitive evaluations were conducted, in addition to B12 assessments. After initial evaluations, the patients were given the option to take a controlled daily multivitamin supplement.
Patients were divided into three groups according to their B12 levels at the beginning of the study. Approximately 13% of the participants had borderline low levels of B12, and 5% had a B12 deficiency. No association was found between low vitamin levels and early motor or cognitive symptoms of Parkinson’s.
The team did find that over time, symptoms in patients with lower B12 levels developed more rapidly than those with higher levels: Patients with lower B12 levels had a significantly reduced ambulatory capacity than patients with higher levels.
“Our findings demonstrate that low B12 levels are associated with greater walking and balance problems, possibly due to the known effect of B12 deficiency on the central and peripheral nervous systems,” Chadwick Christine, MD, UCSF neurologist and lead author of the study, said in a university press release. “Alternatively, low B12 may have a direct effect on the progression of Parkinson’s disease, or it may be a marker of an unknown associated factor, perhaps correlating with another aspect of the disease or nutritional status.”
Subsequent analysis showed improved B12 levels in about 50% of participants, indicating they had chosen to take the multivitamin supplement. Disease progression in this group of patients was found to be much slower, based on the annualized average increase of disability on the Unified Parkinson’s Disease Rating Scale (UPDRS) score — a measure of Parkinson’s disability. Patients with improved B12 levels had an increase to only 10.11 on the scale, showing less disability, compared with 14.38 in patients who maintained low B12 levels throughout the study.
The team also evaluated the blood levels of homocysteine, an amino acid that is usually elevated in people with low B12 levels. There was a significant association between high levels of homocysteine — thus lower B12 — and faster cognitive decline.
“Our results suggest that the measurement of B12 levels early in Parkinson’s may be beneficial,” Christine said. “If levels are at the low end of normal, supplementation to get the level into the middle or upper end of the normal range may slow development of symptoms.”
Further studies are warranted to shed light on how vitamin B12 might benefit Parkinson’s patients, and to fully address its therapeutic potential on disease progression.
The study was supported by funding from the Michael J. Fox Foundation, and gifts from the Ko and Tsu family and William and Mary Ann S. Margaretten.