Folic acid fortification linked to lower stroke death rates

The number of deaths from stroke in North America has dropped by five per cent since the introduction of folic acid fortification, while figures in the non-fortifying UK have not changed.

Mandatory fortification of certain food with folic acid was introduced in the US and Canada in 1998 with the primary outcome designed to be a reduction of birth defects. The programm has been successful in cutting the number of children born with neural tube defects by over 25 per cent.

Researchers from the US Centers for Disease Control and Prevention (CDC) compared stroke mortality rates in the United States and Canada for 1990 to 1997, and 1998 to 2002, with stroke mortality rates in England and Wales.

“The epidemiological analysis presented here certainly does not establish causality, but the trends we observed are consistent with the hypothesis that folic acid fortification is contributing to a reduction in stroke deaths,” wrote lead author Quanhe Yang in the journal Circulation (Vol. 113, pp. 1335-1343).

For the United States population, the levels of homocysteine decreased across all age groups and races studied after the introduction of fortification.

As could be expected, the folate levels in the blood increased significantly, giving more support for the hypothesis that folic acid can reduce stroke mortality.

“If folic acid fortification is responsible for even a fraction of the accelerated improvement we observed, this public health benefit is an important bonus to the reduction in neural tube defect rates previously demonstrated,” said Yang.

The results are presented only days after the publication of two large intervention trials, the Heart Outcomes Prevention Evaluation (HOPE) 2 trial and the Norwegian Vitamin (NORVIT) trial, which both reported no benefits of B vitamin (including folic acid) supplementation on patients with heart disease or recovering from a heart attack.

Courtesy of nutraingredients.com

Steve - it is exciting that this news comes so soon on the heels of this week's NEJM B-vitamin study. The new data that appears in Circulation echoes what was found in the NORVIT studies: B-vitamins may lower homocysteine, a known caridac risk factor, and may lower stroke risk.

For our response to the NEJM study, please read the blog entry from March 14th.