Navigation Links
Meta-analysis shows no heart benefits for folic acid supplements
Date:10/11/2010

Use of folic acid supplements appears to lower blood levels of the amino acid homocysteinetheorized to be a risk factor for heart and blood vessel diseasebut does not appear to be associated with reduced rates of cardiovascular events, cancer or death over a five-year period, according to a meta-analysis of previously published studies in the October 11 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

"Elevated plasma total homocysteine [an amino acid created by the body, usually as a byproduct of eating meat] has been suggested as a potentially modifiable risk factor for coronary heart disease, stroke and other occlusive vascular conditions," the authors write as background information in the article. High rates of cardiovascular disease in children with homocystinuriaa rare genetic condition causing extreme elevations in homocysteine levelsled researchers to hypothesize that moderate increases in blood homocysteine levels may increase cardiovascular disease risk in the general population.

Supplementation with B vitamins, and in particular folic acid, lowers blood homocysteine levels and reduces cardiovascular disease risk among individuals with homocystinuria. Several large clinical trials conducted in patients without the condition have been inconclusive. "Consequently, a collaboration between their investigators was established in 2004 to conduct a meta-analysis based on individual participant data from all large randomized trials of folic acidbased B-vitamin supplementation intended to lower plasma homocysteine levels for the prevention of cardiovascular disease," the authors write.

Robert Clarke, F.R.C.P., University of Oxford, England, and colleagues in the B-Vitamin Treatment Trialists' Collaboration report the results of the meta-analysis of all eight trials completed by the end of 2009. Of a total of 37,485 participants, 18,723 were assigned to take folic acid in doses ranging from 0.8 milligrams per day to 40 milligrams per day. The other 18,762 took placebo or an equivalently small dose of folic acid. Trials continued for a median (midpoint) of five years.

Among the 37,485 participants, 9,326 had a major vascular event during the treatment period, 3,010 developed cancer and 5,125 died. Overall, there was a 25 percent reduction in homocysteine levels associated with active folic acid supplementation. However, those who took folic acid were no less likely to have a major heart or blood vessel event than those who took placebo (4,670 or 24.9 percent of first events occurred in those taking folic acid, compared with 4,656 or 24.8 percent in the placebo group).

In addition, there was no significant difference between folic acid and placebo groups in the number of patients experiencing major coronary events (2,019 or 11.4 percent vs. 1,971 or 11.1 percent); stroke (747 or 4.2 percent vs. 781 or 4.4 percent); new cases of cancer (1,541 or 8.7 percent vs. 1,469 or 8.2 percent) or death (2,578 or 13.8 percent vs. 2.547 or 13.6 percent).

"The doses of folic acid used in all the trials included in this meta-analysis exceeded those required for near-maximal reduction in homocysteine levels," the authors write. "The randomized trials in the present meta-analysis found no evidence of benefit with treatment continued for more than five years. Although some benefit might emerge with even longer treatment and follow-up, the trial results give no reason to expect this (particularly because cardiovascular benefits tend to emerge within just a few years with other cardioprotective treatments, such as antihypertensives or statins)."

"One-third of adults in the United States and one-quarter of those in the United Kingdom report taking daily multivitamin supplements containing folic acid," they conclude. All doses in the trials were greater than those required in the United States, where foods are fortified with folic acid to prevent neural tube birth defects. "Although the lack of any other benefits is disappointing (albeit fairly definitive), the lack of any significant adverse effects on vascular events, cancer incidence, cancer mortality and overall mortality provides reassurance about the safety of population-wide folic acid fortification."


'/>"/>

Contact: Robert Clarke, F.R.C.P.
robert.clarke@ctsu.ox.ac.uk
JAMA and Archives Journals
Source:Eurekalert

Related biology news :

1. Meta-analysis: Radiotherapy variants improve survival in non-metastatic lung cancer
2. Investigational ovarian cancer drug shows promise against platinum resistant disease
3. New study shows benefits of Bt corn to farmers
4. T cell discovery shows promise for Type 1 diabetes treatment: UBC-CFRI study
5. 1st census shows life in planet ocean is richer, more connected, more altered than expected
6. New USDA study shows extent of land degradation and recovery on western rangelands
7. Study shows real partners are no match for ideal mate
8. In-country OB/GYN training programs contributed to retention of doctors in Ghana, U-M study shows
9. Garlic oil shows protective effect against heart disease in diabetes
10. New study shows over one-fifth of the worlds plants are under threat of extinction
11. Nature Nanotechnology paper shows enzyme-controlled movement of DNA polymer through a nanopore
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/15/2016)... , June 15, 2016 ... report titled "Gesture Recognition Market by Application Market - Global Industry ... - 2024". According to the report, the  global gesture ... in 2015 and is estimated to grow at ... billion by 2024.  Increasing application of ...
(Date:6/7/2016)...  Syngrafii Inc. and San Antonio Credit Union ... integrating Syngrafii,s patented LongPen™ eSignature "Wet" solution into ... result in greater convenience for SACU members and ... existing document workflow and compliance requirements. ... Highlights: ...
(Date:6/2/2016)...   The Weather Company , an IBM Business (NYSE: ... capability in which consumers will be able to interact with ... via voice or text and receive relevant information about the ... Marketers have long sought an advertising solution that can create ... relevant and valuable; and can scale across millions of interactions ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... 23, 2016 A person commits a crime, and ... to track the criminal down. An outbreak of ... Drug Administration (FDA) uses DNA evidence to track down the ... Sound far-fetched? It,s not. The FDA has increasingly used a ... of foodborne illnesses. Put as simply as possible, whole genome ...
(Date:6/23/2016)... --  EpiBiome , a precision microbiome engineering company, today ... from Silicon Valley Bank (SVB). The financing will allow ... drug development efforts, as well as purchase additional lab ... been an incredible strategic partner to us – one ... provide," said Dr. Aeron Tynes Hammack , EpiBiome,s ...
(Date:6/23/2016)...  Blueprint Bio, a company dedicated to identifying, protecting ... has closed its Series A funding round, according to ... "We have received a commitment from Forentis Fund that ... meet our current goals," stated Matthew Nunez . ... complete validation on the current projects in our pipeline, ...
(Date:6/23/2016)... Windsor, Connecticut (PRWEB) , ... June 23, 2016 ... ... will introduce a new line of intelligent tools designed, tuned and optimized exclusively ... place September 12–17 in Chicago. The result of a collaboration among several companies ...
Breaking Biology Technology: