New study claims caution with B12

[Jon Bergsma]

Dear Jeff,

Today the following news was published in the Netherlands.
Association of Plasma Concentration of Vitamin B12 With All-Cause Mortality in the General Population in the Netherlands
Jose L. Flores-Guerrero, MD, MSc1; Isidor Minović, PhD1,2; Dion Groothof, BSc1; et al

Study does not say how much b12 is too much. But it seems dr Mc Dougall had a point when he warned for too much B12.

https://jamanetwork.com/journals/jamane ... le/2758742

So now we obviously want to how much is safe and necessary.

Greetings,

Jon

[JeffN]

From the full text....

"Several limitations of this study also need to be addressed. First, the PREVEND cohort study mainly comprises individuals of European ancestry, which could limit extrapolation of our findings to other races/ethnicities. Second, we did not have measurements of vitamin B12 plasma concentrations beyond baseline assessment, which limited us to evaluate the regression dilution of vitamin B12. Third, we only had access to pharmacy records on injectable vitamin B12 supplementation, but not for over-the-counter tablets, which could limit the implication of cobalamin supplementation; likewise, we had no data on reason for performing the vitamin B12 injections."

In Health
Jeff

[Jon Bergsma]

Thanks, Jeff! It was all in the news over here but not much of a study for such strong conclusions. I will keep on the one- two tablets a week of 1000mcg as recommended!

Jon

[JeffN]

Thanks, Jeff! It was all in the news over here but not much of a study for such strong conclusions. I will keep on the two tablets a week of 100mcg as recommended!

Jon

You said, “as recommended.” Whose recommendation is that?

If you were to have any concern, this study is based on serum levels, not supplement intake levels and the best results were in the group with serum levels under 340. So, the only application, if any, would be to your serum levels. Of course serum levels are influenced by your intake levels. If one were to try and apply this, one would check their serum levels and their urinary methyl malonic acid levels and adjust accordingly.

In Health
Jeff

[Jon Bergsma]

Sorry Jeff I made a mistake I meant 1000 and have corrected that.

[JeffN]

This looks like a great example of the problem with observational studies and that correlation is not causation. 

We might expect higher levels of serum Vitamin B12 in meat eaters so the higher mortality rate associated with elevated serum B12 may simply be due to the association between eating meat and higher serum B12.  Meat eaters also have higher serum ferritin levels than vegans and if you look at table 1, you can see that the only other variable that went up significantly in B12 quartiles was serum ferritin.

Either way, my comments above still apply as a pre-caution.

In Health
Jeff