High-Dose Folic Acid May Protect Against Heart Attack Damage
In a new study, an international team of heart experts at Johns Hopkins and elsewhere report that rats fed 10 milligrams daily of folate, also known as folic acid or vitamin B9, for a week prior to heart attack had smaller infarcts than rats who took no supplements. On average, researchers say, the amount of muscle tissue exposed to damage and scarred by the arterial blockage was shrunk to less than a tenth.
The team’s findings, set for publication in the April 8 edition of the journal Circulation, come just weeks after other international studies in humans suggested that low-dose folic acid supplements may prevent dementia in the elderly and premature births.
“We want to emphasize that it is premature for people to begin taking high doses of folic acid,” says senior study investigator David Kass, M.D., a professor at The Johns Hopkins University School of Medicine and its Heart Institute.
“But if human studies prove equally effective, then high-dose folate could be given to high-risk groups to guard against possible heart attack or to people while they are having one,” says Kass.
The more likely and most practical advantage to ingesting supplements, he says, lies in folic acid’s potential to act as a short-term buffer for people who may be having a heart attack and who rush to their local emergency room complaining of chest pain.
Clinical trials are expected in the near future, although Kass says a major challenge in testing is that a high dose of folic acid for humans comparable to that given the rats would require an average-size adult to swallow more than 200 one-milligram pills per day, “an impractical and unrealistic regimen, even if the body excretes the excess.”
In addition, he cautions, “we do not yet know if folate is safe to consume in this high a dose, or how much or how little of it is needed to be effective,” citing 25 milligrams per day as the highest dose previously tested safe to consume in adults as.
When a heart attack occurs: will a folic acid pill perform better than aspirin?
Your chest hurts. Sweat pours from your brow. You are short of breath. You reach for an aspirin tablet in hopes its blood-thinning properties will clear up a clot that may have formed in any of your four coronary arteries, inducing a heart attack. Researchers now think a folic acid pill may be a better choice than aspirin.
Fertile women are frequently given ultra-high dose folic acid pills to prevent birth defects should a pregnancy develop, but high-dose folic acid may just have found a more emergent use – in the ambulance ride to the hospital following a heart attack.
The data are only preliminary and experiments only conducted in animals, but they are striking. After 30 minutes of intentional impairment of blood flow to the heart, a 10-milligram dose of folic acid (vitamin B9) in a 1-pound laboratory mouse (equivalent to a 1600 mg dose in a 160-pound human) produced the following results:
+ Helped the heart to pump about three times more blood than animals not given folic acid. The amount of blood pumped by the heart, called the ejection fraction, was 73% for folic-acid treated rodents, 27% for untreated animals.
+ Maintained the pumping action of the heart: 37% muscle contracture for folic acid treated animals, compared to just 5% in untreated animals.
+ Helped the heart tissues to maintain energy (ATP) levels needed for muscle contraction. ATP levels were three times greater among folic acid-treated animals.
+ Reduced the amount of reactive oxygen radicals following an induced heart attack.
+ Reduced the percentage of abnormal heart beats following a heart attack, which led to fatalities, from 36.7% to 8.3%.
+ Reduced the scarred area of heart tissue by about 20 fold (60.3% in untreated animals to 3.8% in animals given folic acid).
A 1-milligram folic acid pill reduced the area of tissue death about as well as the 10-milligram dose in these small animals, which would be equivalent to about a 16-milligram folic acid pill in an adult human. Up to 25 mg single doses of folic acid have been used safely in humans. [Circulation. 2008 Mar 24, 2008]