|Aflatoxin and vitamin A|
|vitamin A and aflotoxins||Janet-Marie Huddle||19.02.98|
|Aflatoxin and vitamin A||Joanne Csete||25.03.98|
|All-for-Health: Health-for-All||Michael Golden||25.03.98|
Date: Thu, 19 Feb 98 10:15:43 EST
Subject: Ngonut: vitamin A and aflotoxins
Does anyone have information on the effect of aflotoxins on vitamin A absorption? Thanks, jamo
Date: Wed, 25 Mar 1998 07:33:41 +0000
From: jcseteatunicef.org (Joanne Csete)
Subject: Ngonut: Aflatoxin and vitamin A.
The vitamin A and aflatoxin question came up at one of our recent regional nutrition meetings in Africa, and Dr James Olson of Iowa State Unversity kindly
put together this brief comment for us. If you think this would be useful to share with anyone, please do so.
Joanne Csete, UNICEF
Date: 3/17/98 3:57 PM
Dear Dr. Csete:
Considerable interactions do exist between vitamin A and aflatoxin. In essence, vitamin A is anti-mutagenic, both in vivo and in vitro, relative to aflatoxin B1-induced liver damage. Similarly, aflatoxin, in damaging the liver, tends to reduce liver vitamin A concentrations. Carotenoids are also effective in reducing DNA damage but somewhat less so than vitamin A.
In order to induce cancer, aflatoxin must be activated by P450 enzymes in the liver. Thereafter, its metabolites form adducts with DNA as well as with proteins, which ultimately lead both to single strand breaks in the DNA as well as to sister chromatid exchanges. Vitamin A and, to a lesser extent, carotenoids seem to inhibit all of these steps.
Thus, the interaction is important in public health, inasmuch as vitamin A deficiency will enhance the susceptibility of individuals to aflatoxin-induced liver damage and a good vitamin A status would tend to limit such damage.
You have asked whether or not aflatoxins affect the utilization and metabolism of vitamin A. I don't believe so, inasmuch as vitamin A absorption from the GI tract should not be affected by the relatively minute amounts of aflatoxin present in the diet. On the other hand, if aflatoxin is causing significant liver damage, then vitamin A reserves might well be reduced.
Some useful recent publications are: Webster et al. (In Vivo 1996;10:113-8); Gradelet et al. (Cancer Letters 1997;114:221-3); Waters et al. (A review: Mutation Research 1996;350:109-29).
I hope that these comments are of use to you.
James A. Olson