Beer : Health and Nutrition

The Impact of Alcohol on Health 141
and follicle-stimulating hormone in the pituitary gland. These have importance for
reproductive functions. Alcohol can interfere with hormone production in the hypothalamus.
In moderate drinkers any effects are short-lived, but the problem for alcoholics
is signi cant (O’Farrell et al. 1998).
This report should be contrasted with that of Heaton and Varrin (1991), who intriguingly
made a study of the impact of alcohol ingestion on two physiological events: yawning
and penile erections. They found that 0.25 mg/kg ethanol had no impact on either
response, whereas twice this amount suppressed erections but not yawning. Relatively
high doses (1–3 mg/kg) had to be injected intraperitoneally for there to be an effect
on both yawning and the erectile response. The authors suggest that alcohol interferes
with neural receptor systems.
One of the most widely reported effects of alcohol is fetal alcohol syndrome (FAS),
in which there are malformations in the child (Streissguth 2001). The child will tend
to be underweight, shorter and possessed of a decreased skull circumference. There
may be certain facial abnormalities, internal de ciencies in joints, and congenital heart
disease. According to Weatherall et al. (1996) this occurs only in women who drink
at least 4 units of alcohol daily throughout early pregnancy, and is greatly increased if
the rest of the diet is not good. It appears that the risks are rather greater when women
binge drink (four or ve drinks at one sitting) rather than consume alcohol moderately,
e.g. one drink daily (Streissguth 2001). A 1987 American study of 32,870 women, of
whom nearly half had taken alcohol during pregnancy, found no cases of FAS. There
was a correlation with prosperity.
Lesser but related problems in children of heavy drinkers are known as fetal alcohol
effect (Clarren & Smith 1978). Here the children are smaller and more excitable.
However, it is unclear how much of the effect is due to alcohol and how much to maternal
deprivation. There appears to be little risk if women drink less than 10–12 units a
week, unless they also smoke.
Stuttaford (1997) says that women need not be teetotal when pregnant, but that they
should only drink at formal or special occasions and with a meal, no more than 2 units
per session and less than 7 units per week.
Alcohol is excreted in breast milk – but at levels unlikely to make baby more than
drowsy (Stuttaford 1997). Koletzko and Lehner (2000) remind us of the received wisdom
that moderate beer consumption may help in the initiation and success of breast-feeding.
It seems that a component of beer, perhaps a barley polysaccharide, promotes prolactin
secretion. The authors further suggest that the relaxing effects of alcohol and hop components
might also have a bene cial impact on lactogenesis. Mennella (2001) offers
a contrary view, saying that maternal alcohol consumption may slightly reduce milk
production and that alcohol transferred to the infant may adversely affect the infant’s
sleep and motor development.