Re: How does alcohol consumption raise blood sugar levels?

In regard to the metabolism of ethanol, the "drunk" dietitian is, in 
general, correct.  The reason that I said that the dietitian is "in 
general" correct is because of the possibility that the some of the ethanol 
may be, indirectly, converted to glucose (see below).  Alcohol 
(specifically, ethanol) is metabolized primarily in the liver.  First, it 
is converted to acetaldehyde, which is then converted to acetate 
(References 1 and 2).  The acetate formed by these reactions can be: 1) 
released into the blood and eventually eliminated in the urine, 2) 
converted to carbon dioxide and eliminated via the lungs or 3) utilized in 
a variety of biosynthetic reactions.  In the last case, the acetate is 
converted to a molecule termed acetyl coenzyme A.  Acetyl  coenzyme A is 
utilized in the synthesis of lipids and amino acids.  In addition, acetyl 
coenzyme A is used in the tricarboxylic acid (TCA) cycle, which produces a 
molecule termed oxaloacetate, which, in turn, can be converted to glucose 
via a process called gluconeogenesis. Thus, it is possible that, 
indirectly, a small amount of an ingested amount of ethanol may be 
metabolized to sugar.  However, I can not tell you definitively that this 
occurs- that is, I am not certain whether the two carbons that enter the 
TCA cycle in the form of acetate are present in the glucose molecule that 
is synthesized, or whether they are lost in the form of carbon dioxide 
during the synthetic steps.  A biochemist knowledgeable in metabolic 
pathways should be able to answer this question for you.  Regardless, only 
a small fraction of an ingested amount of ethanol would be converted to 
glucose and this probably does not contribute significantly to the observed 
effects of ethanol on blood sugar in diabetics (see below).

Consumption of ethanol by diabetics can elevate, or lower, blood sugar 
levels, depending on whether the individual has recently eaten, or has been 
fasting, and whether the individual chronically consume alcohol, or not 
(Reference 3-4).  Chronic consumption of alcohol by well-nourished 
diabetics is associated with hyperglycemia (increased blood sugar).  
Reference 3 states that "The mechanism(s) underlying the increasing 
hyperglycemia in chronically drinking diabetics are still unknown".  There 
are some suggestions that this may be the result of reduced insulin 
responsiveness (reference 4).  Acute (single exposure) consumption of 
moderate amounts of alcohol by a well-nourished diabetic (either type 1 or 
2), who does not chronically consume alcohol, generally, "does not lead to 
significant changes in blood sugar levels" (reference 3).  Alcohol 
consumption by people who are in the fasting state (i.e., they have not 
recently eaten) produces hypoglycemia (reduced blood sugar levels).  This 
effect occurs in both type 1 and type 2 diabetics, as well as in 
non-diabetics (reference 3).




REFERENCES
1 Weathermon & Crabb  (1999)  Alcohol Research & Health World Vol. 23, No. 
1, pp. 40-54.

2 http://www.madsci.org/posts/archives/aug2000/967651805.Bc.r.html

3 Emanuele, Swade, & Emanuele  (1998) Alcohol Research & Health World Vol. 
22, No. 3, pp. 211-219.

4 Gordis  (1994)  Alcohol Alert, National Institute on Alcohol Abuse and 
Alcoholism No. 26 PH352 October 1994.