Scot Brown-0942021
Question 3
What are the environmental effects of alcohol, caffeine, and their metabolites?
Alcohol, specifically ethanol, has 3 major metabolites in humans. Ethanol is oxidized to
form Acetaldehyde, which is converted to Acetic Acid, which eventually becomes and Acetyl
CoA enters the Krebs cycle which eventually converts the initial alcohol into carbon dioxide and
water. (Jacobsen, 1951) Obviously the Carbon dioxide and water will not have any effect on the
environment because they are excreted regardless of the consumption of alcohol. The Acetyl
CoA and acetic acid will have no effect because they will not be excreted at all, near one
hundred percent of both compounds will be metabolized into carbon dioxide and water.
(Jacobsen, 1951) The only compounds which could have any effect are the alcohol itself or the
acetaldehyde. Acetaldehyde is a known carcinogen, and there is much concern over the emission
of aldehydes like acetaldehyde in the combustion of fossil fuels due to its carcinogenic
properties. (Zhang, 1994) However, Aldehydes are carcinogens because they are readily
oxidized in humans and upon oxidation can create an hydroxide free radical, which causes lipid
peroxidation and other negative effects. (Lieber, 2005) the fact that acetaldehyde is readily
oxidized in humans means that it will not be excreted in significant quantities and will not affect
the environment. Ethanol itself has little to no environmental effects unless it is in large
concentrations, which cannot be obtained in the urine of a human. None of alcohol’s metabolites
nor the alcohol itself have any significant environmental effects.
The major metabolite of caffeine is paraxanthine, However paraxanthine is further
metabolized before excretion. Ninety percent of the paraxanthine metabolized is accounted for.
Fifty percent of the initial paraxanthene is converted to 1-MX (1-methylxanthine) and 1-MU (1-
methyluric acid), an additional seventeen percent is AFMU (5-Acetylamino-6-Formylamino-3-
Scot Brown-0942021
MethylUracil), eight percent was 1,7 - Dimethyluric acid, six percent was 7-MX (7-
methylxanthine), and nine percent was unchanged. (Lelo, 1989) because the excreted metabolites
which are under ten percent will be in such small concentrations their environmental effects will
be negligible. AFMU’s effects on the environment are not well researched so presumably there
are no extreme negative environmental effects, although experiments should be performed to
verify this assumption. not much research has been done to indicate that 1-methyluric acid is a
polluntant but it has been shown to behave as an antioxidant in humans and is actually beneficial
as a method of preventing cancer. (Maples K. R., 1988) 1-methylxanthine is a similar compound
to caffeine, and will behave in a similar way if it is introduced into an organism through the
excretions of the human.( Snyder S H, 1981) even though the 1-methylxanthine will affect other
organisms, the concentrations they will be exposed to will be negligible. Overall, neither
Caffeine nor Alcohol will have a significant effect on the environment, but they may affect the
human body as they are metabolized.
Scot Brown-0942021
Scot Brown-0942021