A study published in the Journal of the American Medical Association (JAMA) suggests that folic acid supplementation does not reduce the risk of benign colorectal tumours and may even increase the risk of higher grade tumours.
I cannot say I am surprised.
1. When you structure a study for a nutrient the same as you would a drug, it is bound to fail. The subjects were 57 years or older who recently had at least one colorectal adenoma removed within three months of enrollment. Researchers were surprised to find more adenomas in the patients who had received folic acid although the risk did not differ significantly between the two groups.
The researchers said this study does not say anything about whether folic acid prevents adenomas in the first place, since all the patients had already had at least one when they were enrolled. It would cost a lot of money and take a long time, to prove that folic acid prevented tumours. "The question of efficacy of folate in cancer prevention is not resolved, and animal experiments showing chemopreventive effects of folate, as well as the strong observational epidemiological evidence, speak to the potential of folate as a chemopreventive agent, if taken early. Unfortunately, primary prevention trials that start in childhood would be lengthy, expensive, and logistically nearly impossible," said reseaarchers.
Bingo! Preventative studies take longer and are more costly.
2. In an accompanying editorial, Dr Cornelia M Ulrich and Dr John D Potter, from the Fred Hutchinson Cancer Research Center in Seattle, said that this study may be raising an issue of timing. If taken early, then perhaps folic acid prevents adenomas from forming, but if taken once they are formed, it could accelerate their development into cancer.
"The most likely explanation for the increased risk of advanced and multiple adenomas in the intervention group is that undetected early precursor lesions were present in the mucosa of these patients (who are at increased adenoma risk), and that folic acid promoted growth of these lesions," they wrote.
They may be right on both accounts. From a preventative standpoint, there is copious research showing the positive effects of folic acid (see below). With regard to folic acid causing more adenomas, this is yet another reason why you see a licensed health professional who is knowledgeable in prescribing dietary supplements.
The fatal flaw in the structure of this study is not recognizing the amount of vitamin B-12 that these subjects were taking, if at all. The fact that these subjects were given folic acid supplements without the aid of separate B-12 or in a multivitamin is an egregious error. Folic Acid and B-12 work harmoniously. B-12 is crucial to digestion, and folic acid in high doses can further reduce B-12 stores if not supplemented. For instance, in research done on seniors, those with low levels of B-12, even with high amount of folate, showed no improvement in mental acuity. However, with normal B-12 stores combined with high folate supplementation, seniors' mental acuity progresses.
3. Mandatory fortification of certain foods with folic acid was introduced in the US and Canada in 1998 in a bid to reduce the incidence of pregnancies affected by neural tube defects. The measure appears to have been a success, with NTD-affected pregnancies reported to have fallen by 26 per cent. Many other countries around the world have a similar program and have seen success. Here is the list of research studies that have appeared on our blog over the past year. Aside from the first two studies (which were performed on sick people, similar to the above adenoma study), all addressed prevention. Would you be surprised to know that these are all positive?
Folic acid won't cut heart risk in patients with history of heart ailments
In seniors with low vitamin B-12 status, high serum folate was associated with anemia and cognitive impairment. When vitamin B-12 status was normal, however, high serum folate was associated with protection against cognitive impairment.
Folic Acid found to cut risk of strokes
Folic acid may prevent hearing loss
Prenatal vitamins with folic acid reduces risk of childhood cancers Folic acid linked to reduced cleft lip in infants
Higher folate levels linked to Alzheimer's risk
Folate, B-6 could boost heart health for type-1 diabetics Folate may aid diabetics
Take folic acid to prevent heart disease
Folic acid may help fertility
Low dose folic acid could reduce homocysteine levels
Folic acid could reduce inflammation and prevent future inflammatory-related disease
Folic acid supplements may prevent cancer progression and promote regression of disease