Beer : Health and Nutrition

The Impact of Alcohol on Health 151
Freudenheim et al. (1995) and Zhang et al. (1999) report that alcohol consumption
seems not to be related to the risk of breast cancer, but Ferraroni et al. (1998) deduce
the opposite, more so for wine than beer, while Hebert et al. (1998) claim that there is
an increased risk of recurrence of breast cancer in beer drinkers. However, to illustrate
the dif culties in relating disease to speci c dietary components, we should consider
the ndings of Jacobsen (1996) that there is an inverse relationship between a woman’s
age when she last gives birth and her tendency to drink beer! Conversely the correlation
is positive with consumption of vegetables and white bread.
Excessive beer drinking is claimed to be associated with an increased risk of colon
cancer, though so too is eating red meat more than twice daily and having a whitecollar
occupation (Hsing et al. 1998). Riboli et al. (1991) suggested a link between
beer drinking and rectal cancer but not colon cancer. Pelucchi et al. (2002) could nd
no link between alcohol intake and incidence of bladder cancer.
It has been said that there is an increased risk of carcinoma in the upper digestive
tract for beer and spirit drinkers (Gronbaek et al. 1998). Conversely, Albertsen and
Gronbaek (2002) and Tavani et al. (1994) say that there is no apparent link between
alcohol consumption (or type) and prostate cancer. Indeed Kampa et al. (2000) draw a
positive correlation between antioxidant polyphenol levels and the inhibition of prostate
cancer cell lines.
In fact there is strong evidence that the consumption of alcoholic beverages in moderation
may actually counter cancer. An international panel of epidemiologists, toxicologists
and pharmacologists penned a letter to the British Journal of Cancer in 1993, which
rmly suggested that moderate intake of alcohol protected rather than caused certain
forms of cancer (Stuttaford 1997). The writers of the letter had re-examined published
data on cancers of the mouth and gastrointestinal tract and concluded that men taking
two drinks per day had half the risk of cancer as those who abstained. Drinking two to
four drinks daily reduced the risk by two-thirds and only those taking a dozen or more
drinks each day had a greater risk of cancer than did abstainers.
There is substantial evidence for the presence in beer of materials that might counter
cancer. Components of beer derived from barley or hops have been studied in isolation
and shown to display a number of promising effects. Several unique avonoid compounds
have been isolated from hops and shown to be present in beer. They have cancer
chemopreventive properties at least in part due to the inhibition of cytochrome P450
enzymes that activate carcinogens (Henderson et al. 2000). The compounds include
xanthohumol, 8-prenylnaringenin and isoxanthohumol.
Miranda et al. (1999) showed that in vitro proliferation of a range of cancer cells
was inhibited by prenylated avonoids of the type derived from hops, especially xanthohumol.
Normal cells were not affected. These molecules may inhibit the activation
of the cytochrome P450 enzymes that catalyse the conversion of procarcinogens into
carcinogens. The material is very effective in stimulating the slow aggregation of breast