Canadian researchers have made a startling discovery about the benefits of folic acid. The nutrient, which is added to foods to prevent neural-tube defects such as spina bifida, also appears to prevent one of the most common forms of childhood cancer.
In fact, the incidence of neuroblastoma, a cancer of the nervous system, has fallen by more than 60 per cent since Canada's fortification of flour and pasta became mandatory in 1998.
"We're very excited by this finding because it's the first time we've prevented a pediatric cancer with a very simple change to maternal diet," said Gideon Koren, director of the Motherisk program at the Toronto Hospital for Sick Children.
He said it also raises the possibility that neuroblastoma could be treated with folic acid, forcing the cancer to disappear.
The research, published in the medical journal Clinical Pharmacology & Therapeutics, will also spur interest in the benefits of folic acid for prevention and treatment of a wide range of conditions.
There is evidence, for example, that folic acid supplementation may also prevent heart malformations in children, prevent some people from developing colon cancer later in life, and even ensure that baby girls are born with healthier eggs, which could reduce the incidence of conditions such as Down syndrome in the next generation.
"Because it's used in the production of DNA, I would not be surprised if it has other implications, including many we have not even yet considered," Dr. Koren said.
Folate -- vitamin B-9 -- is found in leafy green vegetables such as spinach, and in legumes such as lentils and kidney beans. The synthetic version, folic acid, is found in commercially prepared grain products and can be bought in supplements.
The recommended daily dose is .4 milligrams, though many scientists are now suggesting that be raised to 1 milligram. A woman would have to eat about eight slices of white bread daily to reach that minimum level. Because almost half of all pregnancies are unplanned, supplements are recommended for all women of child-bearing age.
Folate is required for the creation of nucleic acids -- the building blocks of deoxyribonucleic acid (DNA). It is particularly important in the first month after conception, when the neural tube forms in the embryo (the neural tube later becomes the baby's spinal cord, spine and brain.)
Without sufficient folate, the neural tube fails to close properly, leaving the brain or spine exposed to amniotic fluid. This, in turn, can lead to neural-tube defects such as spina bifida (when the spinal cord and backbone do not develop properly), anencephaly (when the brain does not fully develop) and encephalocele (when a portion of the brain protrudes from the skull).
Neuroblastoma is a cancer of the nervous system, so it is biologically plausible that it is influenced by folate levels.
Studies have shown that, since the fortification of flour, pasta and cornmeal became mandatory, women have doubled their intake of folic acid and the rate of neural-tube defects in Canada has fallen by half.
The incidence of neuroblastoma has fallen even more sharply, to 6.2 cases per 1,000 births, from 15.7 cases per 1,000 births.
But Dr. Koren thinks the benefits could be even greater if women consumed more folic acid. His research has shown that the majority of Canadian women do not get adequate folic acid from fortified food alone.
"The typical Canadian woman is getting only 200 to 300 micrograms, well below the protection level," he said. "It is perhaps time to consider raising the levels in flour."
While supplements such as a daily multivitamin would do the trick, polling has shown that only about 4 per cent of women who are planning to have a child know they should be taking folic acid to prevent birth defects.
"The benefits are so great, I'm not sure we should be leaving this to chance," Dr. Koren said.
André Picard