Folic acid was ‘consistently’ associated with significant reduced thickening of artery walls – so called carotid intima-media thickness (CIMT), according to findings published in the peer-review journal Atherosclerosis.
“CIMT has proved to be a good marker for both the presence of early atherosclerosis and the degree of atherosclerosis within an individual,” wrote researchers from Anhui Medical University and Peking University First Hospital.
“Our [new analysis] demonstrated a significant linear relation between baseline CIMT levels and the decrease of CIMT. These results provide further evidence that folic acid therapy is more suitable for populations with a high CVD [cardiovascular disease] risk.”
The potential role of B vitamins in heart health, by reducing levels of the amino acid homocysteine reported to increase the risk of cardiovascular disease, is controversial.
Epidemiological studies have linked increased blood levels of the amino acid homocysteine to an increased risk of cardiovascular disease (CVD). It has been suggested that by lowering the levels of homocysteine in the blood with B-vitamins, people could cut the risk of CVD.
However, clinical trials including participants at risk of, or already suffering from, cardiovascular disease have produced null results, with some experts arguing that short term B vitamin supplementation should not be expected to reverse the long-term development of heart disease.
A recent meta-analysis concluded that supplements of B vitamins (folic acid, B6 and B12) may reduce the risk of stroke by about 12% (Clinical Nutrition, doi: 10.1016/j.clnu.2011.01.003).
Data from the new study adds to the potential heart health benefits of folic acid, and found that supplementation was associated with less hardening of the arterial walls, particularly in people with chronic kidney disease (CKD) or with a high risk of high cardiovascular disease (CVD).
The analysis, which included data from 10 clinical trials involving a total of 2,052 people, also found that the benefits were even greater when the researchers used data from trials that reported the greatest reductions in homocysteine levels. High levels of the amino acid homocysteine have been linked to heart disease.
“Our results suggest that homocysteine reduction may be a stronger effect modifier than baseline homocysteine concentration.
“Most importantly, our meta-analysis proved that it is impossible that folic acid supplementation could increase the progression of atherosclerosis, irrespective of baseline homocysteine concentrations,” added the researchers.
June 2012, Volume 222, Issue 2, Pages 307-313
“Effect of folic acid supplementation on the progression of carotid intima-media thickness: A meta-analysis of randomized controlled trials”
Authors: X. Qin, M. Xu, Y. Zhang, J. Li, X. Xu, X. Wang, X. Xu, Y. Huo