The Elusive Moon

Preventing Strokes with Folic Acid: An Elusive Truth

Preventing strokes for just a penny a day is a pretty good deal. It took a very careful study design and execution to finally prove that folic acid could reduce the risk of strokes by 21% in people with hypertension. The study that did it was a randomized, controlled study of 0.8mg of folic acid in 20,702 people taking enalapril for hypertension, just published online in the Journal of the American Medical Association (JAMA).

The possibility that this strategy would work has been debated for years. More than 20 years ago, observational studies found a link between low levels of folic acid and cardiovascular disease. Prior controlled studies have produced few positive results — perhaps because of the population studied or perhaps because of the endpoints chosen.

But absence of proof is not proof of absence.

The population targeted for this study — Jiangsu and Anhui provinces in China — had enough people with low levels of folates to show an effect. The endpoint — first stroke in people with hypertension — was targeted so that the effect would not be hidden by other factors like other treatment regimens and variations in baseline patient characteristics.

In a companion editorial, Meir Stampfer and Walter Willett were effusive, saying:

These remarkable findings may represent an underestimate of the potential true effect of folic acid supplementation in this setting for several reasons.

The trial by Huo et al has important implications for stroke prevention worldwide. Although the trial participants all had hypertension, it is likely that the results would apply to normotensive persons, although the absolute effect would be smaller.

Fortunately, in the U.S. population, low folate levels are rare because grain products are fortified with folic acid to prevent birth defects. In fact, that’s why some of the early studies of this strategy failed to find a benefit.

While the need for further supplementation may be minimal in the U.S., such an inexpensive strategy for preventing strokes worldwide will be a boon.

Click here to read more from HealthDay, here to read the study, and here to read the companion editorial.

The Elusive Moon, photograph © Liam Moloney / flickr

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2 Responses to “Preventing Strokes with Folic Acid: An Elusive Truth”

  1. March 17, 2015 at 6:34 am, Joe Gitchell said:

    This is cool!

    As I’m too lazy to need more, a question: is there a clear mechanism suggested for how folate helps reduce the risk of stroke?

    • March 17, 2015 at 10:46 am, Ted said:

      Thanks, Joe, for making me look.

      The short answer to your question is yes. Folates affect multiple pathways responsible for CVD pathology. The long answer may be found here: