Folic acid: good for cells, so-so as a disease-fighter

You want nice, healthy cells? Then you better make sure you get enough vitamin B9, also known as folic acid or folatein its naturally occurring form.

The vitamin is primarily found in green, leafy vegetables like spinach, lettuce and turnip greens. If that doesn't appeal to you, beans, peas, citrus fruits and squash provide what you need. Still not impressed? There's always liver.

Health Canada figured you might need more enticement than that, too, so back in 1998, the federal government ordered that whole-grain breads, cereals, flour, cornmeal and pasta all be fortified folic acid. Some breakfast cereals now contain between 25 per cent and 100 per cent of the recommended daily dose of folic acid, which is 400 micrograms.

Developing healthy cells is vitally important for humans especially among women who are pregnant or hoping to become pregnant. Folate deficiency has been linked to neural tube defects, in which the central nervous system fails to develop fully in the fetus, leading to defects such as spina bifida and anencephaly malformations of the skull and brain.

Since the 1930s, it had been known that folic acid helped prevent anemia during pregnancy. In the mid-1960s, scientists discovered that folate deficiency might be the cause of neural tube defects, in which the central nervous system fails to develop fully in the fetus.

By the 1990s, research was showing that most North Americans weren't getting enough folic acid. Scientists still don't know how folic acid reduces the risk of neural tube defects in developing babies. But they've been telling women of child-bearing age since 1992 to make sure they're getting enough folic acid, through supplements, if necessary.

In the decade since, some foods have been fortified with folic acid, rates of birth defects related to neural tube defects have fallen dramatically in Canada. According to a 2004 study, rates of neural tube defects fell by 78 per cent in Newfoundland and Labrador, since the introduction of folate-fortified foods.For Canada as a whole, the rate had fallen by as much as 46 per cent, according to Health Canada.

In December 2010, researchers saidblood tests showed40 per cent of Canadians had high folate concentrations, after taking age, sex and socio-economic status into account.

Less than one per cent of Canadians showed folate deficiencies.

Among women of childbearing age the population that fortification is meant to benefit 22 per cent were below the level considered safe to guard against neural tube defects.

Another study, releasedonline in the British Journal of Medicinefound that the number of babies born with severe congenital heart defects has dropped significantly in Quebec since Canada introduced folate-fortified foods. The study by researchers at McGill University found thatrates of severe congenital heart defects have fallen by six per cent a year since 1998.

More health benefits?

Medical researchers have been taking a closer look at folic acid to see if it has other health benefits.

Over the past few years, there have been suggestions that making sure you get enough folic acid could help reduce your risk of developing diseases such as Alzheimer's, heart disease and certain types of cancer.

But the jury is still out on many of the findings. The research is inconclusive on the benefits of folic acid.

Dementia

In February 2008, South Korean researchers reported that a lack of folic acid may lead to a threefold increase in the risk to developing dementia in old age. The study followed 518 people between 2001 and 2003. All were over the age of 65.

During the two-year period, 45 people were diagnosed with dementia, 30 of them specifically with Alzheimer's disease, seven with vascular dementia and four with other forms of dementia.

Those participants who had been low in folic acid at the start of the study were 3.5 times more likely to develop the condition.

Meanwhile, a study released in October 2008, found that B vitamins including folic acid were of no help in slowing the development of Alzheimer's. The study suggested that for people who took high doses of B vitamins, cognitive test scores for memory and language didn't improve much, compared with those who took placebos.

Heart disease

In June 2007, a study published in the medical journal Lancet, suggested thatfolic acid supplements may reduce the risk of stroke.

That was the good news. The bad news was that other studies seem to show folic acid in combination with other B vitamins seemed to increase the risk of heart disease.

When the American Heart Association released new guidelines on prevention of heart disease and stroke in women in February 2007, the group concluded folic acid supplements were worthless for preventing heart disease.

Another study of heart attack survivors released in December 2008 found that folic acid is ineffective in the treatment of and prevention of cardiovascular disease in people who already have heart disease.

Cancer

Folic acid is critical to the development of healthy cells, so it seems a no-brainer that it would show promise in the prevention of cancer. Well, scientists say it's a lot more complicated than that.

The research, they say, has been ambiguous at best.

The American Cancer Society notes that low levels of folic acid have been linked to higher rates of colorectal cancer, but it remains unclear whether increasing intake of folic acid will reduce your risk of developing colorectal cancer.

A November 2006 study suggested that too little folic acid raised the risk of colon cancer in mice. It was thought that the findings could shed light on whether the deficiency plays a role in the risk of humans.

Less than a year later, a study in the Journal of the American Medical Association found that high doses of folic acid do not prevent precancerous colon polyps in people prone to them and may actually increase the risk of developing the growths. It followed several other studies that suggested that taking too many vitamins may actually be harmful.

The researchers suggested that cancer patients should discuss taking vitamins with their doctors, and anyone over 50 who takes vitamins should have a colorectal screening test.

In November 2008, another study in the Journal of the American Medical Association found that B vitamin supplements have no effect in preventing cancer in women.

The study found while there seemed to be no beneficial effect, there was no harmful effect either.

Eye disease

While you might not ward off cancer or Alzheimer's, there's new evidence thatfolic acid and other B vitamins may help prevent age-related macular degeneration in older women. It is the leading cause of blindness in people 65 and older.

More than a third of Canadians between the ages of 55 and 74 develop the condition, which causes of layer of the eye to deteriorate. That leads to a blurring of the centre of the field of vision.

The study found that women who took a combination of B vitamins B-6, folic acid and B-12 had a one-third lower risk of developing macular degeneration after seven years compared to women who were given placebos.