Headlines in major news publications and TV news stations drew attention yesterday with various headlines stating something like "Vitamins cause cancer." It's always interesting how the small number of studies on the use of vitamins and minerals that show a possible association with health concerns draw much more media attention than the large number of studies showing their benefit.
Folic Acid, Vitamin B12 and Cancer
The study that generated the "Vitamins Cause Cancer" headlines was published November 18 in the Journal of the American Medical Association. The study was completed in Norway. Performing the research study in Norway was interesting in that the country does not have a standardized policy for folic acid fortification like the United States does, so people have less exposure to higher levels of folic acid. The researchers concluded that folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause (any reason for) mortality in patients with ischemic heart disease in Norway. The main cancer that occurred during the study was lung cancer. The published review included data from two different research studies, the Norwegian Vitamin Trial (NORVIT) and the Western Norway B Vitamin Intervention Trial (WENBIT). The structure of the study and the results have been questioned by some experts in the world of vitamin and mineral research.
Daniel Fabricant, PhD, is the Vice President of Scientific and Regulatory Affairs for the Natural Products Association (NPA). He pointed out that participants in both studies were also being treated with beta-blockers and statins, and some were also being treated with ACE inhibitors and diuretics. The studies did not adjust for these. Without adjusting for these additional therapies, it cannot be determined how the results came to be.
Andrew Shao, PhD, Vice President, Scientific and Regulatory Affairs for the Council for Responsible Nutrition (CRN), Washington, D.C. was quoted as saying the results from this study:
"are inconsistent with the larger body of data and that this effect has not been observed previously. In fact, as the authors themselves point out, 'Epidemiological studies have demonstrated no associations between intakes of folate or folic acid and lung cancer risk. Consumers, as well as researchers and healthcare professionals, must not lose sight of the safe, well-established benefits of folic acid supplementation and fortification for women of childbearing age to prevent neural tube defects, as well as other potential benefits of folic acid supplementation, such as for cardiovascular health and cognitive function in the general population."
Another unique aspect of the study was the very high prevalence of smoking in the Norwegian population compared with the averages in the United States. In fact, 40% of the participants were current smokers. Of all of the lung cancers diagnosed, 70% were current and 24% were former smokers. While this single study in a a very specific subset of the population may have raised some red flags, it should not stop people from ensuring they take in optimal levels of these vitamins.
An additional article, also published in the November 18 issue of JAMA, titled Assessing Cancer Prevention Studies - A Matter of Time, the authors explain that the occurrence of cancer has actually decreased during the time that folic acid fortification has taken place in the United States, which goes against the study findings. They also said:
"Cancer prevention efforts to not start or end with folic acid. Cessation of cigarette smoking and prevention of smoking in youth and adolescents remains the highest priority for cancer prevention. For those who do not smoke, eating a healthy diet and exercising to avoid weight gain or maintain weight loss will translate to lower risk of cancer, diabetes, and other chronic conditions. These are population-wide changes that take time, and the benefits of such lifestyle changes can take years, even decades to realize."
Benefits of Folic Acid and Vitamin B12
There is a significant amount of research on the benefits of folic acid and Vitamin B12 supplementation. Some of the conclusions from other studies on Vitamin B12 and folic acid are listed below:
Taking a daily supplement including both folic acid and vitamin B12 would reduce the risk of coronary heart disease, as well as provide a cost effective means of maintaining health
A daily regime of aspirin or B-Vitamins may help reduce the risk of dementia and cognitive impairment
The use of vitamin B12, B6 and folate supplements aids in recovery after heart surgery
Folate, vitamin B6 and vitamin B12 help to improve cognitive functions such as memory, processing speed and verbal abilities
Vitamin B12 has been proven to be a pain reliever, and is safe and well-tolerated
This is a very small sample of the conclusions of other studies on folic acid and vitamin B12 which doesn't begin to describe all of the potential benefits of optimal folic acid and vitamin B12 intake. The evidence overall suggests a strong need for the use of folic acid and vitamin B12, consumed through food and supplements. Even though the headlines make for an attention-grabbing story, be sure to get all of the facts surrounding the use of vitamin and mineral supplements before you consider giving up on an an important component of a sound nutrition program. They don't replace the need for nutrition from food, but are an important part of ensuring your take in optimal levels of these essential micronutrients.
In health,
References:
Tice JA, Ross E, Coxson PG, Rosenberg I, Weinstein MC, Hunik MG, Goldman PA, Williams L, Goldman L. Cost-effectiveness of vitamin therapy to lower plasma levels for the prevention of coronary heart disease: effect of grain fortification and beyond. JAMA. 286(8):936-43, 2001 Aug 22-29
Clarke R, Harrison G, Richards S. Effects of vitamins and aspirin on markers of platelet activation, oxidative stress and homocysteine in people at high risk of dementia. Journal of Internal Medicine. 254(1):67-75, 2003 Jul.
Schnyder G, Roffi M, Pin R, Flammer Y, Lange H, Eberli FR, Meier B, Turi ZG, Hess OM. Vitamin B12 aids Heart Surgery Recovery. New Eng Jour Med. 345(22)1593-600, 2001 Nov 29
Bryan J, Calvaresi E, Hughes D. Vitamin B12 Helps to Improve Memory. Jour of Nutr. 132(6)1345-56, 2002 Jun.
Mauro Gl, Martorana U, Ctaldo P, Brancato G, Letzia G. Vitamin B12 for Lower Back Pain. Europ Rev for Med & Pharm Sci. 4(3):53-8, 2000 May-Jun
Neutraceuticals World. Study Links Folic Acid with Cancer Risk. neutraceuticalsworld.com
Ebbing M, Bonna KH, Nygard O, Arnesen E, Ueland PM, Nordrehaug JE, Rasmussen K, Njolstad I, Refsum H, Nilsen D, Tverdal A, Meyer K, Vollset SE. Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12. JAMA. 2009;302(10):2119-2126
Drake B, Colditz G. Assessing Cancer Prevention Studies - A Matter of Time. JAMA 2009;302(19):2152-2153
This article is not intended for the treatment or prevention of disease, nor as a substitute for medical treatment, nor as an alternative to medical advice. Use of recommendations in this and other articles is at the choice and risk of the reader.
