I recently had a patient come in expressing concern about folate, a B vitamin and colorectal cancer. A relative had told her that recent research had suggested the connection. She was concerned because she was taking a nutritional supplement I had recommended, 5-MTHF which is what your body converts folate or folic acid into before it can be used. A fairly large percentage of the population (about 40%) has a genetic problem that interferes to a greater or lesser extent in this important conversion.

I told my patient that’s I had not heard of a connection between folate and colorectal cancer and would check it out. I asked her if her relative had a reference for this study so I could see how the study was conducted and what it really said. On her next visit she brought me a page from the Mayo Clinic newsletter talking about the study. There wasn’t a lot on information about the study in the newsletter so I went to the Internet.

Here’s what I found out. The study 2006 Mayo was talking about was not a well conducted study. It did not really link folate to and type of cancer. All it did was to look at the incidence of colorectal cancer from the time of U.S.mandatory folate fortification (1998) of things like cereals and breads. In addition, the concern was for man-made folate overwhelming the conversion to 5-MTHF and leaving lots of folate floating around. Since 1998 the study found that there had been an increase in colorectal cancer rates. There was no effort to look at
other possible causes of higher colorectal cancer rates, like other dietary or lifestyle or environmental changes. This is sort of like having a patient tell me that, after eating breakfast, they developed severe low back pain. In might suspect that they had an adverse reaction to something they ate for breakfast if I didn’t question them further and find out that they spent the rest of the morning moving rocks for a patio in their backyard!

There was a later study published in the July 2011 issue of “Gastroenterology”. This study, involved around 100,000 participants from 1999 to 2007. In that time there were 1023 cases of colorectal cancer diagnosed. After looking at folate intake in the involved group and crunching the numbers, the study found that there was *no* evidence for increased rates of colorecta cancer with increased folate intake. In fact the study found that folate intake from all sources were associated with a 19 percent *reduction* in colorectal cancer rates!

For more details and a link to the published study, visit the American Cancer Society website or click on this link:


Considering all the known benefits of folate supplementation, especially 5-MTHF supplementation including prevention of neural tube defects in fetuses, anemia prevention, small intestine health, energy production and serotonin (anti-depressoin) production, I’m more than a little upset that a publication like the Mayo newsletter has been spreading warnings about this important nutrient. Something to keep in mind is that scientific studies are often flawed or slanted. It’s important to look at how the studies were done and even who financed them. Finally, if research results are valid, they will be backed up in future studies. Most new information is not considered valid until it has been reproduced in several subsequent and independent studies.

The bottom line: Folate and especially 5-MTHF has not been found to actually cause colorectal cancer and may actually help to prevent it!