High B12 levels and increased cancer risk

[Frank]

Prostrate cancer is a big killer in the male population and still gets relatively low exposure.

Feel free to add your stories of Prostrate cancer and the treatments that have been endured/recommended on this thread.


Breaking Medical News

*Milk and Prostate Cancer: New Evidence *

A new study in the //International Journal of Cancer// highlights the
link between dairy consumption and prostate cancer. Researchers examined
dairy and calcium intake in 29,133 men in the Alpha-Tocopherol,
Beta-Carotene Cancer Prevention Study. As consumption of dairy products
or overall dietary calcium intake increased, risk for prostate cancer
increased. Men who consumed the most dietary calcium (greater than 2,000
mg per day) had a 63 percent greater risk, compared with those getting
less than 1,000 mg per day.

Several previous studies have linked dairy products with prostate
cancer. The new study adds to evidence that a principal reason may be
dairy calcium. Excess dietary calcium inhibits activation of vitamin D
in the body; vitamin D is essential for prostate health. Even though
milk products in the U.S. are fortified with vitamin D, their large
calcium load tends to block vitamin D activation in the body.

Mitrou PN, Albanes D, Weinstein SJ, Pietinen P, et al. A prospective
study of dietary calcium, dairy products and prostate cancer risk
(Finland). //Int J Cancer//. 2007;120:2466-2473.

For information about nutrition and health, please visit www.pcrm.org/ (http://www.pcrm.org/)
<http://support.pcrm.org/site/R?i=CrHTbmv0FNoibvx6jqDsDw..>.

Breaking Medical News is a service of the Physicians Committee for
Responsible Medicine, 5100 Wisconsin Avenue, N.W., Suite 400,
Washington, DC 20016.

Physicians Committee for Responsible Medicine
5100 Wisconsin Ave., N.W., Ste. 400
Washington, DC 20016

[Korn]

I've already mentioned this study in our B12 overdose (http://www.veganforum.com/forums/showthread.php?t=169) thread, but since this isnt really about B12 overdosing, but about the link between high B12 levels and prostata risk, I thought this study deserves it's own thread, so here we go:



http://www.psa-rising.com/eatingwell/vb12_folate04.html



[...]But when the Swedish team compared blood levels of these factors to prostate cancer risk in a prospective study of 254 men with prostate cancer and 514 matched men without known prostate cancer, they found something odd and surprising.

Folate and B12 were expected to be protective against prostate cancer, because folate, vitamin B12 and homocysteine are essential for methyl group metabolism and thus also for DNA methylation. Abnormal methylation, primarily hypermethylation of certain genes including tumor suppressors, has been implicated in prostate cancer development.

But in fact, increasing plasma levels of folate and vitamin B12 were statistically significantly associated with increased prostate cancer risk, with an odds ratio of 1.60 for folate and 2.63 for vitamin B12 for highest vs. lowest quartile.

Increasing plasma homocysteine levels were associated with a reduced risk of borderline significance.

After adjustment for body mass index and smoking, a statistically significant increased risk remained only for vitamin B12.

The researchers say: "Our results suggest that factors contributing to folate status are not protective against prostate cancer. On the contrary, vitamin B12, associated with an up to 3-fold increase in risk, and possibly also folate, may even stimulate prostate cancer development. These findings are novel and should be explored further in future studies."


More here:
http://www.nature.com/ncpuro/journal/v2/n3/full/ncpuro0134.html


B12 is also associated with lowering cancer risk. Too much or too little of something normally isn't a good idea.

[Korn]

Here's some relevant comments from Dr. McDougall's (http://www.drmcdougall.com/misc/2008nl/may/fav5.htm) site:



Animal Fat May Accelerate Prostate Cancer

Saturated fat intake predicts biochemical failure after prostatectomy by Sara Strom in the June 2008 issue of the International Journal of Cancer showed, “that high prediagnostic saturated fat (HSF) intake was associated with a 2-fold increased risk of biochemical failure in this cohort of 390 Caucasian men with localized PCa treated with prostatectomy…Men who were both obese and consumed HSF diets had the shortest biochemical-failure-free-survival (19 months), and nonobese men who consumed LSF diets had the longest biochemical-failure-free-survival (46 months, p < 0.001).”1The study was based on a food frequency questionnaire. Biochemical failure was determined by a significant rise in prostate specific antigen (PSA) levels.

Comment:

Studies of populations of people and laboratory studies of animals consistently show that foods, especially meat, dairy, and added free fats cause and promote the growth of prostate cancer. This study says the diet eaten by a patient with prostate cancer can influence the growth of the cancer. Saturated fat, which is primarily found in red meat, chicken, milk, and cheese, cuts in half the time it takes for the cancer to come back (based on PSA). It is fair to assume this same rich diet will cause the patient to die sooner.

Saturated fat is just one cancer-promoting component of the rich Western diet. The cholesterol, animal protein, and environmental chemicals found in these foods are also known to make cancer grow faster. Just as important are the missing ingredients. Dietary fiber, vitamins and minerals, and thousands of other plant-derived (phyto) chemicals keep the body healthy by discouraging cancer growth.

A study by Dean Ornish has begun to show the benefits of a truly healthy diet, like ours, for prostate cancer patients.2 Published in the September 2005 issue of The Journal of Urology, his research found, “Intensive lifestyle changes may affect the progression of early, low grade prostate cancer in men.” A total of 93 men with elevated PSA levels (4 to 10 ng/ml), with a Gleason score of less than 7, and who had not undergone conventional treatments, were split into two groups. For one year, one group followed a low-fat vegan diet and the other continued with the American diet (control group). Because of a rise in PSA levels or signs of disease progression, 6 in the control group eventually underwent conventional therapy (surgery, radiation, chemotherapy) – none in the vegan diet group required further treatment. PSA decreased 4% in the vegan diet group and rose 6% in the control American-diet group.

Because money for research comes primarily from pharmaceutical companies, and secondarily from food companies making their money from the products that are causing and promoting cancer, too little research proving the benefits of a low-fat, plant-food based diet is likely to ever be done. The result is simply more suffering and death of your friends and relatives.

1) Strom SS, Yamamura Y, Forman MR, Pettaway CA, Barrera SL, DiGiovanni J. Saturated fat intake predicts biochemical failure after prostatectomy. Int J Cancer. 2008 Jun 1;122(11):2581-5.

2) Ornish D, Weidner G, Fair WR, Marlin R, Pettengill EB, Raisin CJ, Dunn-Emke S, Crutchfield L, Jacobs FN, Barnard RJ, Aronson WJ, McCormac P, McKnight DJ, Fein JD, Dnistrian AM, Weinstein J, Ngo TH, Mendell NR, Carroll PR. Intensive lifestyle changes may affect the progression of prostate cancer. J Urol. 2005 Sep;174(3):1065-1070.

[Korn]

Some more links about prostate cancer and animal products:

From dfwnetmall.com
Dairy and Prostate Cancer (http://dfwnetmall.com/veg/milkcancerprostate.htm)

From cancerproject.org:
Prostate Cancer: Prevention and Survival (http://www.cancerproject.org/survival/cancer_facts/prostate.php)

Cancer of the prostate is strongly linked to what men eat. Again, animal products are consistently indicted: Milk, meat, eggs, cheese, cream, butter, and fats are found, in one research study after another, to be linked to prostate cancer.

From physicians-background.com:
Milk and Prostate Cancer (http://www.physicians-background.com/pro.html)

From drmirkin.com:
Does milk cause cancer? (http://www.drmirkin.com/men/8334.html)

[Korn]

Here's (http://www.pnas.org/cgi/reprint/0803080105v1?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=Christopher+M.+Haqq%2C+and+Peter+R.+Carro ll&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT) a study from 2008 on a group of men with prostate cancer who changed their lifestyle and started to live on a predominantly plant based, low-fat diet..


"The 30 men who enrolled did not undergo surgery or radiation therapy to treat their
low-risk tumors; rather, they underwent comprehensive lifestyle changes (low-fat, whole-foods, plant-based nutrition; stress management techniques; moderate exercise; and participation in a psychosocial group support)."

Among the changes they observed in the 30 men, was "changes in prostate gene expression". THe gene related changes happened after only three months and affected 500 gens (favorably).

More about the link between prostate cancer and intake of animal products (and high B12 levels) here (http://www.veganforum.com/forums/showthread.php?t=16897).

[Hemlock]

http://news.bbc.co.uk/1/hi/health/7655405.stm





Meat 'ups prostate cancer risk'


http://newsimg.bbc.co.uk/media/images/44823000/jpg/_44823620_prostate_cred226.jpg Hormone may stimulate development of cancer cells

Eating meat and dairy products may increase the risk of prostate cancer, research suggests.
Such a diet raises levels of a hormone called Insulin-like Growth Factor-1 (IGF-1) which promotes cell growth.
A University of Oxford team examined the results of 12 studies, featuring a total of nearly 9,000 men.
They found men with high blood levels of IGF-1 were up to 40% more likely to develop prostate cancer than those with low levels.
The study appears in the journal Annals of Internal Medicine.
IGF-1 plays a key role in the growth and development of children and adolescents.
In adults it continues to regulate cell growth and death, but it can also inhibit the death of cells which have come to the end of their natural life cycle.
Extent unclear
Lead researcher Dr Andrew Roddam said the degree to which diet influenced IGF-1 levels was unclear.
But he said levels could be up to 15% higher in people who ate a lot of meat and dairy products.
Dr Roddam said: "There is a need to identify risk factors for prostate cancer, especially those which can be targeted by therapy and/or lifestyle changes.
"Now we know this factor is associated with the disease we can start to examine how diet and lifestyle factors can affect its levels and whether changes could reduce a man's risk."
Dr Roddam said raised levels of IGF-1 were likely not only to increase the risk of developing prostate cancer, but also to aid the spread of tumours.
Research shows that cells fed IGF-1 grow much more quickly.
However, Dr Roddam said there was no evidence to suggest that measuring IGF-1 levels could be used to develop a new test to screen for prostate cancer.
Each year in the UK more than 34,000 men are diagnosed with prostate cancer and around 10,000 die of the disease.
Dr Lesley Walker, of the charity Cancer Research UK, which funded the study, said: "While there are established risk factors associated with prostate cancer of age, family history, and ethnicity, there are no clear data on modifiable risk factors."

[gogs67]

And, funnily enough, studies have shown that masturbation can lower the risk as well, so if yer a veggie wanker then it's a good chance something else will kill you rather than the P cancer!

It's a scary disease, was speaking to a doctor friend the other week and he was saying that if a man lives to be 85 then he WILL have prostate cancer 99% certain. It may not be malignant but cancerous cells will be present in the gland.

[Animosity]

*This has nothing to do with the thread, I apologize* but I totally read the title of the thread as: "Meat increses prostitution." :lol: To stay on topic, Wow, gogs67... I never realized guys were that likely to get it... That is pretty scary.

[Korn]

As already mentioned in various threads (see list below), there is a link between some cancer types and animal product intake. The main difference between a vegan and meat based diet (in terms of nutrients) is the B12 intake.

Cancer, adaptation and the vegan diet (http://www.veganforum.com/forums/showthread.php?t=19904)

Cancer and animal products (http://www.veganforum.com/forums/showthread.php?t=18)

Red Meat 'Linked To Breast Cancer' (http://www.veganforum.com/forums/showthread.php?t=14371)

Bacon & Skinless Chicken Associated With Bladder Cancer / Dairy Products May Increase Testicular Cancer Risk (http://www.veganforum.com/forums/showthread.php?t=12735)

Red meat and cold cuts linked to colorectal cancer (http://www.veganforum.com/forums/showthread.php?t=2536)


I came across an article/discussion today about a possible link between using injectible B12 supplements and brain tumor risk:
http://www.tradersnarrative.com/confessions-of-a-methylcobalamin-junkie-669.html

My only concern with taking B-12 is that there is some limited evidence to that suggests there is a higher risk of developing a brain tumor when using injectable B12 supplementation. The current reasoning as to why this may happen has to do with the manner in which B-12 works in the brain. B-12 supplementation can help protect the existing structures in the brain as well as assist the brain in repairing certain structures.
These effects can also be used by harmful cancerous cells, thus allowing a brain tumor to form or accelerate in growth through the use of B-12 concentrations that would not otherwise exist in the body.

Still, though, there is conclusive link, just anecdotal evidence. I believe that the potential benefits outweigh the risks. Still, there are risks. Just very low probablility.



However, there is no link to the sources for these findings - has anyone here seen this report? There's also a post in that discussion suggesting links between "the cyanide form of B-12 has resulted in blindness" - and another poster writes about a link between using cyanocobalamin (the most common for of B12 in supplements) and organ damage (both claims are without links/sources).

This info would maybe have been better off in the B12 overdose/megadose (http://www.veganforum.com/forums/showthread.php?t=169) thread, but 'side effects', 'B12 overdose symptoms' and links between high intake of B12 and certain types of cancer are all related to each other...

Links between high B12 levels and cancer have been reported several times, both in humans and animals. It wouldn't surprise me if B12 is the link between the increased cancer rate among meat eaters either.

Furthermore - maybe the fact that humans have been including meat in their diet, maybe the body is 'defending itself' from overdosing on B12 by reducing it's ability to synthesize it's own....? (More about this later!)


Animal-Based Nutrients Linked With Higher Risk Of Stomach And Esophageal Cancers (http://www.sciencedaily.com/releases/2001/10/011030225654.htm)
ScienceDaily (Oct. 31, 2001) — Yale School of Medicine researchers have found that a diet high in cholesterol, animal protein and vitamin B12 is linked to risk of a specific type of cancer of the stomach and esophagus that has been increasing rapidly.

[Korn]

Red and Processed Meat Increases Risk of Prostate Cancer (http://www.pcrm.org/news/archive091008.html)
This was published on PCRM's site today.

[Korn]

Folate and B12 were expected to be protective against prostate cancer, because folate, vitamin B12 and homocysteine are essential for methyl group metabolism and thus also for DNA methylation. Abnormal methylation, primarily hypermethylation of certain genes including tumor suppressors, has been implicated in prostate cancer development.

But in fact, increasing plasma levels of folate and vitamin B12 were statistically significantly associated with increased prostate cancer risk, with an odds ratio of 1.60 for folate and 2.63 for vitamin B12 for highest vs. lowest quartile.

Increasing plasma homocysteine levels were associated with a reduced risk of borderline significance.

After adjustment for body mass index and smoking, a statistically significant increased risk remained only for vitamin B12.

The researchers say: "Our results suggest that factors contributing to folate status are not protective against prostate cancer. On the contrary, vitamin B12, associated with an up to 3-fold increase in risk, and possibly also folate, may even stimulate prostate cancer development. These findings are novel and should be explored further in future studies."

It's too bad that The Vegan Society's site, which now has an article (http://www.vegansociety.com/uploadedFiles/About_The_Society/Publications/The_Vegan_magazine/Feature_Articles/Prostate%20cancer%20and%20diet%20update.pdf) dedicated to prostate cancer, doesn't even mention these findings. They still seem to belong to the group of vegans and non-vegans who claim that one should never worry about taking too much B12 (http://www.veganforum.com/forums/showthread.php?t=169), which often happens to be the same people who, when discussing the association between B12 and homocysteine/heart disease (http://www.veganforum.com/forums/showthread.php?t=108), never mention the ongoing controversy about this topic.

[Korn]

Here's a link already posted in another thread:
Cancer Incidence and Mortality After Treatment With Folic Acid and Vitamin B12 (http://jama.ama-assn.org/cgi/content/short/302/19/2119)
An excerpt:

Results During study treatment, median serum folate concentration increased more than 6-fold among participants given folic acid. After a median 39 months of treatment and an additional 38 months of posttrial observational follow-up, 341 participants (10.0%) who received folic acid plus vitamin B12 vs 288 participants (8.4%) who did not receive such treatment were diagnosed with cancer (hazard ratio [HR], 1.21; 95% confidence interval [CI], 1.03-1.41; P = .02). A total of 136 (4.0%) who received folic acid plus vitamin B12 vs 100 (2.9%) who did not receive such treatment died from cancer (HR, 1.38; 95% CI, 1.07-1.79; P = .01). A total of 548 patients (16.1%) who received folic acid plus vitamin B12 vs 473 (13.8%) who did not receive such treatment died from any cause (HR, 1.18; 95% CI, 1.04-1.33; P = .01). Results were mainly driven by increased lung cancer incidence in participants who received folic acid plus vitamin B12. Vitamin B6 treatment was not associated with any significant effects.

Conclusion Treatment with folic acid plus vitamin B12 was associated with increased cancer outcomes and all-cause mortality in patients with ischemic heart disease in Norway, where there is no folic acid fortification of foods.

[Korn]

Nov 14, 2010: Does Milk Cause or Promote Prostate Cancer? (http://www.cancersupportinternational.com/artman/publish/article_470.asp)

ETA 2011 - more here:
http://www.pcrm.org/health/prevmed/milk_prostate.html
http://chetday.com/prostatecancermilk.htm

[Korn]

I've already mentioned this study from 2001 in another thread:
Animal-Based Nutrients Linked With Higher Risk Of Stomach And Esophageal Cancers (http://www.sciencedaily.com/releases/2001/10/011030225654.htm)

ScienceDaily (Oct. 31, 2001) — Yale School of Medicine researchers have found that a diet high in cholesterol, animal protein and vitamin B12 is linked to risk of a specific type of cancer of the stomach and esophagus that has been increasing rapidly.

Here's another study which was released a week ago:
High Intake of Folate from Food Sources Is Associated with Reduced Risk of Esophageal Cancer in an Australian Population. (http://www.ncbi.nlm.nih.gov/pubmed/21178085)
This is good news for vegans, because it's hard not to have good folate levels on a plant based diet.

In addition to finding a link between low folate levels and esophageal cancer, the same study also found that supplemental thiamin, riboflavin, niacin, and vitamin B-12 were associated with increased esophageal adenocarcinoma risk. The study also found that cancer risk is increased with folate from supplements, but not with folate from food:


Increasing intake of folate from foods was associated with reduced EAC risk (P-trend = 0.01) and mitigated the increased risks of ESCC associated with smoking and alcohol consumption. In contrast, high intake of folic acid from supplements was associated with a significantly elevated risk of BE with dysplasia. High intakes of riboflavin and methionine from food were associated with increased EAC risk, whereas increasing betaine intake was associated with reduced risks of BE without (P-trend = 0.004) or with dysplasia (P-trend = 0.02).

[khadagan]

That's such a worrying statistic about the b12 and high meat intake. I wish they would publish these findings straight on the main msn.com page or some place like that so a lot of people could read this!

[VagabondVegan]

Just need one of those shock medical programs made by Vegans showing ALL these studies I think. 6 part documentary series? :) put it on Channel 4 (UK) with a title like...can't think of one but something to do with animals being dangerous generally catches attention.

[khadagan]

Yeah that would be good! I used to love Channel 4 in the UK btw, shame you can't get it here in Canada;).

I would just love itif this sort of information would be more easy to find for people because all the info is already out there, but you always need to make an effort to find it. I would like it if people had no excuse and can't say 'oh but 'I didn't know'. I think a regular show on channel 4 or the BBC would be good. :)

[VagabondVegan]

I think a regular show on channel 4 or the BBC would be good. :)

ORRRRRRRR....a Vegan TV channel! :O...VEGANVISION...and Veganvision +1 just for double exposure :)

[khadagan]

I would love a vegan tv channel!! I think they should add a regular vegan cooking show to any food channel. Maybe drop a few facts in there, not too many though, you don't want to put anyone off by preaching ;), more importantly show people how nice vegan foods can be and you really don't need any animal foods

[VagabondVegan]

http://www.youtube.com/watch?v=rYX18NGTwls
Just remembered this and another video where they told people who were suffering from diet based illness and made them all go vegan and saw how much they improved after 2 weeks, can't find the video of a Texas cowboy kinda guy who was crying after he saw how much his health improved.

[khadagan]

Re: Several studies link high B12 and meat intake to esophageal cancer http://www.youtube.com/watch?v=rYX18NGTwls Just remembered this and another video where they told people who were suffering from diet based illness and made them all go vegan and saw how much they improved after 2 weeks, can't find the video of a Texas cowboy kinda guy who was crying after he saw how much his health improved.

Thanks for posting this link, very interesting!

[Korn]

Here's a similar report from American Association for Cancer Research (Feb 2010)
Circulating Folate, Vitamin B12, Homocysteine, Vitamin B12 Transport Proteins, and Risk of Prostate Cancer: a Case-Control Study, Systematic Review, and Meta-analysis (http://cebp.aacrjournals.org/content/19/6/1632.abstract)

Am excerpt from the abstract:

Results: In the ProtecT study, increased B12 and holo-haptocorrin concentrations showed positive associations with prostate cancer risk [highest versus lowest quartile of B12 odds ratio (OR) = 1.17 (95% confidence interval, 0.95-1.43); Ptrend = 0.06; highest versus lowest quartile of holo-haptocorrin OR = 1.27 (1.04-1.56); Ptrend = 0.01]; folate, holo-transcobalamin, and tHcy were not associated with prostate cancer risk. In the meta-analysis, circulating B12 levels were associated with an increased prostate cancer risk [pooled OR = 1.10 (1.01-1.19) per 100 pmol/L increase in B12; P = 0.002]; the pooled OR for the association of folate with prostate cancer was positive [OR = 1.11 (0.96-1.28) per 10 nmol/L; P = 0.2) and conventionally statistically significant if ProtecT (the only case-control study) was excluded [OR = 1.18 (1.00-1.40) per 10 nmol/L; P = 0.02].

Conclusion: Vitamin B12 and (in cohort studies) folate were associated with increased prostate cancer risk.

Impact: Given current controversies over mandatory fortification, further research is needed to determine whether these are causal associations. Cancer Epidemiol Biomarkers Prev; 19(6); 1632–42. ©2010 AACR.

[Korn]

Animal foods, protein, calcium and prostate cancer risk: the European Prospective Investigation into Cancer and Nutrition (http://www.nature.com/bjc/journal/v98/n9/full/6604331a.html)


We examined consumption of animal foods, protein and calcium in relation to risk of prostate cancer among 142 251 men in the European Prospective Investigation into Cancer and Nutrition. Associations were examined using Cox regression, stratified by recruitment centre and adjusted for height, weight, education, marital status and energy intake. After an average of 8.7 years of follow-up, there were 2727 incident cases of prostate cancer, of which 1131 were known to be localised and 541 advanced-stage disease. A high intake of dairy protein was associated with an increased risk, with a hazard ratio for the top versus the bottom fifth of intake of 1.22 (95% confidence interval (CI): 1.07–1.41, Ptrend=0.02). After calibration to allow for measurement error, we estimated that a 35-g day−1 increase in consumption of dairy protein was associated with an increase in the risk of prostate cancer of 32% (95% CI: 1–72%, Ptrend=0.04). Calcium from dairy products was also positively associated with risk, but not calcium from other foods. The results support the hypothesis that a high intake of protein or calcium from dairy products may increase the risk for prostate cancer.
British Journal of Cancer (2008) 98, 1574–1581. doi:10.1038/sj.bjc.6604331 www.bjcancer.com
Published online 1 April 2008

[Consistency]

x

[Korn]

Here's another site mentioning 'troubling' B12/cancer connections: Is a Vitamin B12 Overdose Safe? (http://www.usingvitaminswisely.com/vitamin-b12-overdose.html):



One case was reported of leukemia resulting from a vitamin B12 megadose used in the treatment pernicious anemia.
http://www.amjmed.com/article/0002-9343%2884%2990872-6/abstract
I have only seen the abstract of that report, and find a bit vague, because it doesn't say clearly that the cancer came from the B12 megadose.

The article Folic acid, B12 may increase cancer risk on webmd.com (http://www.webmd.com/cancer/news/20091117/folic-acid-b12-may-increase-cancer-risk) mentions lung cancer risk:



This finding was mainly driven by an increase in lung cancer (http://www.webmd.com/lung-cancer/default.htm) incidence among the folic acid and B12-treated patients.
Seventy-five (32%) of the 236 cancer-related deaths among the study participants were due to lung (http://www.webmd.com/lung/picture-of-the-lungs) cancer, and the cancer incidence among the study group was 25% higher than in the population of Norway as a whole.

Roughly 70% of all the patients in the study were either current or former smokers, including more than 90% of those who developed lung cancer.



Other Views


In a statement issued in response to the study, a spokesman for the supplement-industry trade association Council for Responsible Nutrition (CRN) noted that the lung cancer finding has not been seen in other studies.

"The real headline of this study should be that smoking (http://www.webmd.com/smoking-cessation/default.htm) increases the risk of lung cancer -- the study found that a total of 94% of the subjects who developed lung cancer were either current or former smokers," CRN Vice President for Scientific and Regulatory Affairs Andrew Shao, PhD, says in a news release.

In the U.S., mandatory folic acid fortification of flour and grains has been in effect for just over a decade, and fortification has succeeded in dramatically lowering the incidence of neural tube birth defects (http://www.webmd.com/baby/tc/birth-defects-testing-what-are-birth-defects-tests).
Shao says the fact that lung cancer rates have also dropped during this time in both men and women suggest folic acid and B12 do not promote lung cancer.
Bettina F. Drake, PhD, of Washington University in St. Louis School of Medicine, says it is not likely that fortification has led to an increase in cancers in the U.S. In fact, several studies suggest just the opposite.
"We would expect to see an excess in cancers within a few years after folic acid fortification began, and we have not seen that," she tells WebMD.
Drake says it is possible that folic acid protects against cancer at certain points in life and promotes the growth of cancers at other times. It may also be true that too little folate in the blood or too much of the B vitamin are both associated with an increased risk for cancer.




It's already known that cancer is associated both with too high and too low levels of B12.