The study investigated B Vitamins and prevention of cognitive decline. Elevation of homocysteine (Hcy) levels is well-established as a risk factor for Alzheimer’s and other types of dementia, yet controversy exists regarding whether B-vitamin-mediated reduction of homocysteine levels can benefit cognitive function.

The review concludes that “the evidence from this meta-analysis suggests that B vitamin supplementation was associated with a reduced rate of cognitive decline, especially in populations who received early intervention and long-term intervention. Pooled results suggest that folate in sufficiency, which already emerged in populations at the MCI stage, is a risk factor for dementia and cognitive decline, and higher intake of folate is associated with a decreased risk of incident dementia in non-dementia aged population. Considering demographic trends in many countries with rapidly aging populations and widespread insufficiency in dietary intake of B vitamins, the findings support the view that public health measures to improve B vitamin status should be targeted at people at risk of cognitive impairment, which would lower the health and societal burdens of dementia”. 

The abstract can be accessed here. 

Wang, Z., Zhu, W., Xing, Y., et al (2021) B vitamins and prevention of cognitive decline and incident dementia: a systematic review and meta-analysis, Nutrition Reviews