Serious adverse effects, even with high doses of injected vitamin B-12,

hydroxylkobalamin, have never been reported.

However, some patients do report acne breakouts after high-dose injections,

which I talked about before.

But hold on. When you look at the relationship between B-12 concentrations in the blood and mortality,

you see graphs like this.

We're having low levels isn't good with higher mortality,

but high levels in the blood is associated with higher mortality too.

What are some of the ways we could get high B12 levels? One could be B12

supplementation, but it could also be due to B12 being released from damaged tissues,

or not clearing as well from malfunctioning kidneys. In other words, reverse causation.

Instead of high B12 causing disease, disease is causing high B12. How could we tease that out? There is a correlation between high blood B12 causing disease, disease is causing high B12. How could we tease that out? There is a correlation

between high blood B12 and cancer, for example, which one might be leading to the other.

Well, when you treat the cancer, when you shrink the tumors, B12 levels drop,

suggesting that the active tumor was the source of high vitamin B12 levels in circulation

instead of vice versa. And that's what you see when you look at other conditions.

The blood B12 concentrations rise as a consequence of acute and chronic illness.

A cause-and-effect relationship between serum B-12 concentrations and subsequent disease or mortality

has never been demonstrated.

In fact, how else can you get lots of B12 in your system by eating lots of meat?

So high B12 levels may be a proxy in some cases for increased intake of meat.

If you go back and separate out the effects of different sources of B12,

...