Beer : Health and Nutrition

122 Chapter Six
containing rather more than this, for instance the Trappist beers, the barley wines and
the so-called ‘super lagers’. This latter genre might contain 9% ABV, so here a halfpint
would constitute 2 units. Butterworth (1993) offers 8–12 g of alcohol as being a
‘standard serving’ (remembering, as we discovered in Chapter 3, that a beer that is 4%
alcohol by volume is 3.2% alcohol by weight).
Individuals differ substantially in their bodily response to alcohol. Various factors
will play a role, including body weight, general state of health, amount of activity, and
whether the alcohol is being consumed on its own or alongside food. The UK guidelines
are precisely that: blueprints to give some guidance to people to judge sensibly what is
and what is not an advisable amount of alcohol to consume. They are not recommendations
to drink: they are certainly not instructions. Rather they are a common-sense
judgement on what is likely to be healthful for a sensible and healthy adult. And the
fact that the levels were increased is testimony to the burgeoning evidence that there is
real merit in moderate consumption of alcohol.
The author of a newspaper article in California once highlighted the number of times
I had invoked the word ‘moderation’ when she interviewed me. I make no apology for
using the word again here (particularly as a glance at the thesaurus in my computer offers
the word temperance as a suggested alternative!). As the reader should surmise from
what follows, there is more than ample evidence for the harmful effects of sustained,
heavy intake of alcohol in all its forms. However, it will be noted that the serious ailments
are primarily associated with extreme alcoholism, and a consequence of vastly
more alcohol ingestion than is the norm for the great majority of adults.
The metabolism of ethanol
Unlike drugs, alcohol is completely metabolisable by the body, at a rate of 10–15 g/h.
The enzyme alcohol dehydrogenase in the stomach commences the metabolism of
ethanol. This is referred to by Halsted (2003) as ‘ rst pass’ metabolism. The enzyme
has a rather poor af nity for ethanol, and it seems that this enzyme deals with about
30% of ethanol metabolism in men, but only about 10% in women, partly explaining
the lower tolerance of women to alcohol.
The rest of alcohol metabolism is in the liver. Here the alcohol dehydrogenase has a
much greater af nity for alcohol, leading to the production of acetaldehyde and much
reducing power. The latter may also spill over to lipid synthesis, lowered production of
carbohydrate (gludoneogenesis), enhanced lactate production and lessened excretion
of uric acid. Consequences may therefore include transient fatty liver, hypoglycemia,
acidosis and gout.
This enzyme seems to deal with all the alcohol (not dealt with by the stomach) in
moderate drinkers. At higher alcohol levels a microsomal enzyme called CYP2E1 kicks