B Vitamins Protect Aging Brains
B vitamins are needed to break down homocysteine, a risk factor for brain atrophy and Alzheimer's disease
New research suggests B vitamins may help lower homocysteine levels, possibly offsetting further decline in people with mild thinking (cognitive) impairment and preventing progression to more serious forms of dementia.
The brain loses some of its mass with age, even in otherwise healthy people. This progressive "brain atrophy" is more pronounced in people with mild cognitive impairment that doesn't interfere with normal functioning, but is characterized by some problems related to memory, thinking, language, and judgment. Brain atrophy is much accelerated in people with advanced dementia, like that seen in Alzheimer's disease.
The homocysteine connection
Higher blood levels of homocysteine, a toxic byproduct of an amino acid, is one risk factor for brain atrophy and Alzheimer's disease. B vitamins are needed to break down homocysteine, so it's been suggested that if they help lower homocysteine levels, they might also be able to slow the rate of brain atrophy.
The new study, which was published in the journal, PLoS ONE, involved 168 people over 70 years old with mild cognitive impairment. The participants were given 0.8 mg folic acid, 0.5 mg vitamin B12, and 20 mg vitamin B6 or placebo every day for 24 months. At the beginning of the study and after two years, MRIs of their brains assessed changes in brain mass.
Blood levels of homocysteine dropped by 23% in the people taking B vitamins, and the rate of brain atrophy per year was almost 30% lower in the B-vitamin group than in the placebo group at the end of the study.
"It is tempting to suggest that this finding is consistent with the view that raised homocysteine is a direct cause of atrophy," the authors commented. "However, it does not exclude that homocysteine is only a marker for low-normal levels of the vitamins, which are themselves the causal factors."
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(PLoS ONE 5:e12244.doi:10.1371/journal.pone.0012244)
Kimberly Beauchamp, ND, earned her bachelor's degree from the University of Rhode Island and her Doctorate of Naturopathic Medicine from Bastyr University in Kenmore, WA. She cofounded South County Naturopaths in Wakefield, RI, and now sees patients in East Greenwich and Wakefield. Inspired by her passion for healthful eating and her own young daughters, Dr. Beauchamp is currently writing a book about optimizing children's health through better nutrition.