Folate and cardiovascular health
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Folate Intake and Cardiovascular Disease Risk
Research consistently shows that higher dietary folate intake is linked to a lower risk of cardiovascular disease (CVD) events and mortality. Large population studies in the UK and Japan found that people who consumed more folate had reduced risks of stroke, heart failure, coronary heart disease, and overall CVD mortality, even after accounting for other risk factors Zhang2022Cui2010. This protective effect was also observed in people with diabetes, prediabetes, or insulin resistance, where increased daily folate consumption was associated with significant reductions in all-cause and CVD mortality .
Folic Acid Supplementation: Benefits and Limitations
Meta-analyses of randomized controlled trials indicate that folic acid supplementation can lower the risk of stroke by about 10% and overall CVD by about 4%, especially in people with low baseline folate levels or those without preexisting CVD . However, supplementation did not significantly reduce the risk of coronary heart disease . The benefits of folic acid supplementation appear to be more pronounced when it leads to a greater reduction in homocysteine levels, a known risk factor for CVD .
Mechanisms: Homocysteine Lowering and Endothelial Function
Folate’s cardiovascular benefits are partly due to its ability to lower homocysteine, which is associated with reduced CVD risk Li2016Verhaar2002. Beyond this, folate may improve endothelial function by increasing nitric oxide (NO) bioavailability, reducing oxidative stress, and supporting the function of endothelial NO synthase Verhaar2002Stanhewicz2016. These effects help maintain healthy blood vessels and may prevent or slow the progression of CVD Verhaar2002Stanhewicz2016.
Folate, Lipids, and Atherosclerosis
Some evidence suggests that folic acid supplementation may modestly improve plasma lipid profiles and reduce early vascular damage related to atherosclerosis, further supporting its role in cardiovascular prevention, particularly in people with dyslipidemia .
Risks of Excess Folate and Supplementation
While moderate folate intake is beneficial, several studies highlight potential risks with excessive folic acid supplementation, especially in people at high risk for CVD. Both very low and very high serum folate levels have been linked to increased CVD mortality, suggesting a U- or J-shaped relationship Xu2021Nkemjika2019Sauer2009. High-dose supplementation may not further reduce CVD risk and could even be harmful in certain populations Xu2021Nkemjika2019Sauer2009. This underscores the importance of achieving adequate, but not excessive, folate intake.
Conclusion
Overall, maintaining sufficient dietary folate intake is associated with lower cardiovascular risk and mortality. Supplementation can be beneficial, particularly for those with low folate status or at risk of stroke, but excessive intake may be counterproductive or harmful. The best approach appears to be ensuring adequate, balanced folate intake through diet, with supplementation considered carefully based on individual risk factors and baseline folate levels.
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