Beer : Health and Nutrition

146 Chapter Six
Alcohol encourages sleep initially, but reduces overall sleep and induces restlessness
by reducing REM sleep time (Vitiello 1997).
Feelings of pleasure have been linked to levels of dopamine in the body (Berridge &
Robinson 1998). Schmidt et al. (2001) report how alcohol-dependent patients display
a reduced sensitivity in their central dopamine receptors.
Kidney and urinary tract
Alcohol dehydrates the whole body (except the brain, which swells) because of a diuretic
impact on the kidney (Olson 1979). This explains the merit of drinking plenty of water
before retiring to bed after drinking.
Buday and Denis (1974) and Piendl and Wagner (1985) have researched the diuretic
effect of beer. Beer is rather more diuretic than is water, and several components,
including organic acids and other yeast fermentation products and polyphenols, are
said to contribute.
A category of persons at risk from consuming beer is those with gout (Eastmond et
al. 1995). Gout is an arthritic condition caused by high levels of uric acid circulating in
the blood. There is an attendant deposition of crystals of urate in connective tissue and
this stimulates an acute in ammatory reaction. Alcohol is certainly not the only cause,
others being gluttony and excessive eating, diuretic pills, infection, and even aspirin.
Alcohol is more of a risk if its intake is not accompanied by proper eating. There is
a major genetic impact on an individual’s predisposition to gout. Susceptible people
need to avoid purine-rich foods such as liver, kidney and shell sh. Some beers may be
a particular problem when compared to other alcoholic drinks because they may contain
signi cant quantities of purines (see Chapter 5).
There is good evidence that beer is superior to water alone in ‘ ushing out’ the
kidneys and protecting the kidney against stones (Curhan et al. 1998; Shuster et al.
1985; Krieger et al. 1996). Hirvonen et al. (1999) observed that beer consumption
was inversely correlated with a risk of kidney stones (urolithiasis), with each bottle of
beer consumed daily being estimated to reduce risk by 40%. The authors say that high
intakes of calcium, potassium and water are associated with lowered risk of kidney
stones. Magnesium intake, too, may have a role. Curhan et al. (1996) also found that
beer, as well as wine, tea and coffee, reduced the risk of kidney stones. Apple juice and
grapefruit juice increase the risk.
In a curious study, Nagao et al. (1999) presented evidence to suggest that the older
and more stale the beer, the less was its tendency to promote urination. Adding materials
to beer that detracted from its quality by introducing unpleasant tastes also lowered
urination rate.