CHAPTER 29: B Vitamins (Folate, B₆ and B₁₂) in Relation to Stroke and its Cognitive Decline

This chapter evaluates the roles of folate, vitamin B₆ and vitamin B₁₂ on stroke. Stroke is one of the leading causes of death in developed countries, but current therapeutic strategies have been largely unsuccessful. Several studies have reported important benefits on reducing the risk of stroke and improving the post-stroke associated functional declines in patients who ate foods rich in micronutrients, including B vitamins. Folic acid, vitamin B₆ and vitamin B₁₂ are all cofactors in homocysteine metabolism. Growing attention has been paid to hyperhomocysteinemia as a risk factor for cardiovascular disease. Hyperhomocysteinemia has been linked to inadequate intake of vitamins, particularly to B group vitamins and therefore may be amenable to nutritional intervention. Hence, poor dietary intake of folate, vitamin B₆ and vitamin B₁₂ are associated with increased risk of stroke. Elevated consumption of fruits and vegetables appears to protect against stroke. After reviewing the observational and intervention studies, there is an incomplete understanding of mechanisms and some conflicting findings; therefore the available evidence is insufficient to recommend the routine use of B vitamins for the prevention of stroke. A better understanding of mechanisms, along with well-designed controlled clinical trials, will allow to further progress in this area.