Doctors at St. Michael’s Hospital in Toronto gave rats supplements of folic acid before conception, during pregnancy and while breast feeding and discovered that the daughters of those rats had a breast cancer rate almost twice as high as rats that were born to mothers who didn’t have the supplement. They also had more tumors that spread at a faster rate than other rats.
Although this doesn’t mean anything for humans – rats are too different to apply the findings to the human species – it does mean that further research in humans needs to be done to see if a similar result occurs.
Women are advised to take a folic acid supplement from three months before conception and during pregnancy to prevent neural tube defects in the baby, such as spina bifida and anencephaly.
However, in recent years the amount of folic acid that women are exposed to has increased dramatically as it is added to foods such as fortified breakfast cereals, white flour, bread and enriched pasta to ensure that women receive enough of the B vitamin. With these in their diet, taking the supplement may be too much of a good thing?
In addition to high concentrations of folic acid being present in food, up to 40 percent of North American’s take a folic acid supplement regularly for health benefits such as anti-aging or as part of their multi-vitamin supplement. While folic acid is good for you and is necessary for human health, there is a growing body of evidence that shows very high levels of folate that are contained in artificial supplements may cause some cancers.
Dr. Young-in Kim headed the study and divided the rats up into two groups. One group was given folic acid supplements equivalent to what pregnant women in North America are given, in addition to the mandatory fortification of some foods. They were given the supplements from three weeks before mating and throughout pregnancy and lactation. After weaning, half the female pups were given the same amount of folic acid as their mothers.
Both the rats whose mothers took folic acid supplements and those who ate a folic acid supplemented diet had a two fold increase in mammary tumors than the control group.
The folic acid given to pregnant rats produced tumors more aggressively than the supplements given to infant rats, suggesting that folic acid supplements have more of an impact on the developing fetus than on babies.
Folate is needed to help make DNA and help it replicate. Poor replication eventually leads to signs of aging and health problems, which is why folic acid is sometimes added to anti-aging creams. However, folic acid supplements appear to affect DNA methylation (the turning on and off of genes) and this likely plays a role in the development of cancer.
Previous studies have shown that folic acid supplements taken before conception can either increase or decrease certain pediatric cancers in offspring. Some of these small, observational studies have linked folic acid to a decrease in neuroblastomas, leukemia and some brain tumors, but others have shown an increase in brain tumors. Kim presented research last year showing maternal folic acid supplements decreased colon cancer in offspring by about 65 percent.
"This means the impact of folic acid supplements may be organ-specific," Kim said. "It may decrease some cancers but promote others."
Essentially, not enough is known about the risks and benefits of taking folic acid before and during pregnancy.
Folic acid can be obtained through eating leafy green vegetables such as spinach, lettuce, broccoli, asparagus and parsley, to name a few.
Source: Cancer Res February 1, 2011 71; 988 - http://cancerres.aacrjournals.org/content/71/3/988.abstract
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book, 'Breast Milk: A Natural Immunisation,' and co-author of an educational resource on disabled parenting, in addition to running a charity for people damaged by vaccines or medical mistakes.