Beer : Health and Nutrition

132 Chapter Six
prime class among the polyphenols, the avonoids, could reduce risk of diseases of the
cardiovascular system in humans. We ascertained in Chapter 5 that beer also contains
this class of molecules.
An inverse link between cardiovascular disease and folate levels in the diet has been
strongly implicated (Riddell et al. 2000). High levels of homocysteine arising from the
metabolism of methionine are associated with increased cardiovascular disease, perhaps
because homocysteine is toxic to endothelial cells (Bellamy et al. 1999; Langman &
Cole 1999). Accordingly homocysteine levels are used as a diagnostic tool for cardiovascular
disease. Increased folate leads to decreased homocysteine (Eikelboom et al.
1999; McDowell & Lang 2000). Folate might also protect against Alzheimer’s disease
(Clarke et al. 1998) and cancer of the colon and cervix (Mason & Levesque 1996).
Ubbink et al. (1998) assessed the homocysteine concentration in the serum of 2290
men to predict ischaemic heart disease. The mean serum total homocysteine concentration
in the men who experienced an ischaemic heart disease event was signi cantly
higher than for the 2136 men who experienced no such event, after standardising for
the effects of differences in age, social class, smoking, body mass index, diabetes,
HDL-cholesterol and prevalent ischaemic heart disease. The vitamin nutritional status
and extent of alcohol intake were signi cant for their reduction of total homocysteine
concentration in the blood serum. The authors explain the effect of alcohol by the folic
acid content of beer, which is the preferred alcoholic beverage in Caerphilly, where the
study was conducted. Halsted et al. (2002) have stressed, however, that binge-drinking
alcoholics display an impediment to folate absorption by an inhibition of the carrier
system needed to transport the vitamin. It is claimed that the folate de ciency accelerated
changes in the methionine metabolism of the liver, with attendant oxidative damage
and alcoholic liver disease.
The hop constituent, xanthohumol, has a strong inhibitory effect on the enzymes in
liver microsomes (rat) that convert diglycerides to triglycerides and so it may reduce
the extent of atherosclerosis (Tabata et al. 1997). Xanthohumol is also active in the
oxidation of low-density lipoprotein (Miranda et al. 2000a).
A nal observation in the area of atherosclerosis is one that perhaps best illustrates
the complexity of the human body and its many interrelated facets, as well as perhaps
the risk of drawing correlations that may or may not have simple causal bases. Thus
Lotufo et al. (2000) conclude that vertex pattern baldness (i.e. balding from the top of
the scalp as opposed to from the front) is a marker for an increased risk of coronary
heart disease. The authors offer an explanation, in that men prone to hair loss in this
way seem to have more androgen receptors and higher levels of testosterone. It is
claimed that the sex hormones directly impact events in the vascular system, leading to
atherosclerosis, thrombosis and hypertension. Baldness, these authors would contend,
is a symptom associated with cardiovascular disease in men, not a cause of it. The logic