A new study from South Korea suggests that those who consume the most folic acid are at a reduced risk for developing colon cancer – if you’re a woman, anyway. Deaths from colon cancer in South Korea have risen steadily in the last few decades, a trend that has been attributed to the rising popularity of a Western−style diet in the country, say the researchers.

Folic acid (otherwise known as folate) is a B vitamin that naturally occurs in green, leafy vegetables (like spinach, mustard, and collard greens), citrus fruits, beans, and yeast. It is also added, sometimes in its full recommended daily allowance, to many cereals and other fortified foods. Pregnant women are encouraged to make sure their diets are high in folate, since it has been shown to reduce the risk of neural tube defects in fetuses and certain congenital diseases.

Those in the top fifth of folate consumption were about half as likely to have the disease as those who consumed the lease amount of folate. But when the researchers looked at men and women separately, they found that the effect did not seem to exist in men.

In the current study, J. Kim and his team at the National Cancer Center in Goyang followed almost 600 colon cancer patients and 500 healthy participants, noting how much folate the participants consumed on average. Those in the top fifth of folate consumption were about half as likely to have the disease as those who consumed the lease amount of folate. But when the researchers looked at men and women separately, they found that the effect did not seem to exist in men. There was a strong effect in women, however: those with the highest folate consumption (at least 300 micrograms per day) had a 64% lowered risk of having the colon cancer than those who consumed the least (200 micrograms per day).

Though factors like smoking, alcohol consumption, and activity level were found to be higher in the colon cancer patients, the researchers controlled for these variables, meaning that the connection between folate and colon cancer was still seen even when these factors were pulled out of the analysis.

Folate plays a key role in cell division, as it is required for the formation of new nucleotides (the “building blocks” for DNA and RNA), and the researchers suggest that it is this aspect that is responsible for the association between folate and colon cancer. If one is deficient in folate, then errors in DNA synthesis leading to mutations could ultimately cause cells to become cancerous. Kim and his team say that their findings are particularly important because they indicate that making simple changes to one’s diet may help protect against cancer in the future.