pen to recall whether he assessed what the vitamin C status was before he did the supplementation?
DR. CLARKSON: No, on the second paper they did check vitamin C levels.
PARTICIPANT: And they were adequate before this?
DR. CLARKSON: Yes, but low.
PARTICIPANT: Based on plasma concentrations?
DR. CLARKSON: Yes.
PARTICIPANT: I just want to make a comment. I don't know if anyone noticed, about a week or two ago in Science magazine, there was just a short note on Dr. Linus Pauling who is still at age 90 consuming 18 grams per day of vitamin C. I don't know what type of effects that would have on absorption and interference that you talk about.
And the other thing, I was also interested in the work in the South Africans on vitamin C apparently accelerating the acquisition of acclimation. Do you know of any other papers that have followed that up? That was mid-1970s; correct?
DR. CLARKSON: Yes, and that is it. I found that one.
PARTICIPANT: I could offer a technical comment. My thesis was on vitamin B12 chemistry and I did study some of the interactions of vitamin C and B12 and so has Victor Herbert (RDA, ninth edition). And a lot of these effects are an artifact of the analytical techniques. I don't take that too seriously.
It turns out that vitamin C plus certain forms of B12 will be generating singlet oxygen and will destroy the chromophore in the test tube. So if you don't prevent this artifact—it is a pro-oxidant when you add it to iron usually.
So a lot of the studies are flawed because they didn't prevent this. You have high C levels carried over in your serum when you are doing analysis in B12.
DR. CLARKSON: In his (Herbert, 1990) recent review of literature on vitamin B12, Herbert suggests that vitamin C does have an effect on absorption of vitamin B12.
PARTICIPANT: Just a comment on vitamin B12. I would think it would be rather unlikely that you would see a B12 deficiency if you were to put adults on a low intake for a period of time. It is going to take a long long time to get a deficiency.