https://www.theatlantic.com/health/a...energy/537654/

There are a few concerning issues with this article.

1) Women not affected? This is a warning sign about the validity of the study.

2) there was little or no comment about folate. Folate is already under analysis for increasing risk of colon cancer. Young women taking 5mg or more given by their doctors to prevent birth defects in their babies, have developed colon cancer. For several years now there has been no definite conclusion concerning this risk.

3) So what form of B12 did these people use? Since it goes back so many years, I wouldn't think the active form called methylcobalamin was being used.

4) Because of the gender split..It is possible that other factors these men were exposed to could be important issues and confounding the data. Eating habits, (no good intake of veggies and fruit which have antioxidant properties) probably were not controlled and accounted for. Males have occupations that expose them to carcinogens. Solvents, heavy metals, and other chemicals like fire retardants are known possible carcinogens.
Mesothelioma (asbestos) causes delayed lung cancers. People who fly regularly are exposed to ionizing radiation over time and this can lead possibly to increased cancer risk.

5) look for words like this in this article:
"could" "increased risk" "may" 'in theory" "appear to cause"

6) I find the caviar (fish eggs) photo very misleading.
Why choose caviar to illustrate animal sourced B12?
Why not a photo of dairy, eggs, and meat, which people consume every day?

There are many more reasons for this study results.
Years ago there was another published meta study on high dose
Vit E and cancer. Over time some researchers explained how flawed that meta study was. I think this one you have linked to will generate interesting discussion too. The best discussion about the Vit E issue which can be found on Linus Pauling Institute was the best I've read.

Here is a link from YouTube that was made by a medical professional who has written a book about hidden B12 deficiency
where doctors do not even test for low B12.
It is a real eye opener:

Diagnosing and Treating Vitamin B12 Deficiency - YouTube

Today, the DNA testing for MTHFR can show if a person needed
methylcobalamin and methylfolate. It used be thought rare but now we know up to 40% of adults could be low in B12 and inherited that defect.

One has to be careful reading lay media articles about medical things...they are often misleading or have frank errors in them.
In this article:
Here is one link from Linus Pauling Institute illustrating the Vit E controversy:
Vitamin E and Prostate Cancer in Healthy Men | Linus Pauling Institute | Oregon State University

Not long after this controversy broke in the lay media, I read an article in Science News magazine, that one theory about the Vit E issue is that antioxidants Vit C and and A have to be present in addition to the E, as they hand off the damaging free radicals to each other and if C and A are not there the radicals have no place to go and build up, and MAY increase damage and cancer
risk. But that is only one scenario IMO.

This is a huge topic. The lay press loves to stir people up with fear to increase attention to themselves. When I saw that "caviar" cover photo, I knew the article to follow could be very problematic!

Adding to the concerns which mrsD has raised, there does not seem to be any independent corroboration of how much Vitamin B12 the subjects took over the period of the study.

Self-reporting ("In 2010 I took X ug per day but in 2011 I took Y ug per day.") is often very unreliable.

In the seeming absence of any independent corroboration I am dubious about the validity of the study.

Joe - Thanks for bringing this to our attention.

After reading the article I decided to research the author - the article appears to be a reflection of his personal viewpoint as an MD and vegan - not that there is anything wrong with that.

From the many other articles he has written as a senior writer at The Atlantic, and a published author, his focus appears to be centered on promoting veganism from both a health and an ethical viewpoint. Again that's fine - we're all entitled to our own opinion.

The article does mention that a deficiency of B12 vitamins can also cause cancer and goes on to discuss the lack of dose regulation in the supplement industry - promoting this agenda may or may not be the underlying intention of the article. However using the headline scare tactic of B vitamins causing cancer to promote a different agenda would be viewed by many as unethical.

The article also makes no mention of those, who for diagnosed health reasons, may require either therapeutic doses of B6 or B12 or to maintain a non-vegan diet.