Folic acid, the 'baby-protector', not only fights spina bifida and some related abnormalities, but new research suggests it may also prevent premature birth and heart defects.
Pregnancy specialists in the United States are asking if it is time for the government to boost the amount being added to certain foods to help ensure mothers-to-be get enough of it. For older adults however, there may be a down side to the nutrient: Extra high levels late in life just might pose a cancer risk.
'Folate is assuming the role of a chameleon, if you will,' said Dr Joel Mason of Tufts University's nutrition research centre, who is researching that possible risk.
Folic acid is an artificial version of folate, a B vitamin found in leafy green vegetables, citrus fruit and dried beans. Everyone needs folate regularly because it is important for healthy cell growth yet the body does not store enough of it.
Women need extra, even before they may know they have conceived. Enough folate in the earliest days of pregnancy can prevent devastating birth defects of the spine and brain called neural tube defects, including spina bifida. Those defects have dropped by about a third since the US mandated fortifying certain breads, cereals and pastas with folic acid in January 1998.
Two major studies in the past month suggest the vitamin has even more protective effect, said an AP report..
First, Texas researchers analysed nearly 35,000 pregnancies. They found that women who reported taking folic acid supplements for at least a year before becoming pregnant cut their risk of having a premature baby by half. Their risk of having very early preemies - babies least likely to survive - dropped even more.
Then Canadian researchers analysed 1.3million births in Quebec since 1990 to look for heart defects, the most common type of birth defect. They found the rate of serious heart defects has dropped 6 per cent a year since Canada began its own food fortification in December 1998.
It is hard to get enough folate for pregnancy through an average diet. So health authorities there have long advised that all women of childbearing age take a daily vitamin containing 400mcg of folic acid.
However, because only about a third of non-pregnant women take precautionary folic acid supplements, fortifying foods made with enriched flour ensures everyone gets a modest amount.
Complicating that issue is the question about cancer risk when older people take lots of folic acid.
Some research shows people who do not eat enough folate have a higher risk of colon and certain other cancers. On the other hand, animal studies show too much folic acid, the pill version, can spur some cancers. There is little human evidence.
However, when researchers studied people prone to pre-cancerous colon polyps, those who took high-dose folic acid - 1,000mcg a day - for three years had more new polyps than people given a dummy pill.
In March, researchers tracked 640 men from that earlier study and found that 10 years later, the folic acid users were more likely to have developed prostate cancer.
Why? While enough folate usually is protective, if people's bodies already harbour some pre-cancerous or cancerous cells, too much may feed their growth, said Dr Mason.
He worries though that some people can rack up the dose with today's multiple sources in fortified foods like cererals, supplements, vitamin-infused bottled water and energy bars.
Everyone should eat enough leafy greens and citrus - good folate from food is important at all ages. However until the issue's settled, Dr Mason said older adults really ought to think twice about whether they should take a vitamin supplement that contains folic acid.
