Vitamin B9Does folic acid lower the risk of stroke?
Updated 9 Nov 2026
Short answer
A little, mainly where grain is not fortified with folic acid. A 2024 review of 21 trials with 115,559 people found 10% fewer strokes (risk ratio 0.90). In areas without fortified grain or with only partly fortified grain the risk ratio was 0.83, and in areas with fortified grain 1.04.[1] In a trial of 20,702 Chinese adults with high blood pressure, 0.8 mg of folic acid with a blood pressure medicine lowered first strokes from 3.4% to 2.7% over 4.5 years.[2] B vitamins that lower homocysteine did not prevent heart attacks.[3]
Sources (3)
- Folic acid supplementation for stroke prevention: A systematic review and meta-analysis of 21 randomized clinical trials worldwide. Zhang N, Zhou Z, Chi X, Fan F, Li S, Song Y, et al. Clin Nutr, 2024. PMID 38824900
- Efficacy of folic acid therapy in primary prevention of stroke among adults with hypertension in China: the CSPPT randomized clinical trial. Huo Y, Li J, Qin X, Huang Y, Wang X, Gottesman RF, et al. JAMA, 2015. PMID 25771069
- Homocysteine-lowering interventions for preventing cardiovascular events. Martí-Carvajal AJ, Solà I, Lathyris D, Dayer M Cochrane Database Syst Rev, 2017. PMID 28816346
More about vitamin b9
What is vitamin B9?Which foods contain folate?What is vitamin B9 used for?Who is likely to be low in folate?Is vitamin B9 safe?How long does folic acid take to raise folate levels?For education; not medical advice. Talk to a doctor before you start, stop or change a supplement.