Beer : Health and Nutrition

138 Chapter Six
contain signi cant levels of residual sugar and unusually low pH (< 4.0) have potentially
harmful effects on teeth (Nogueira et al. 2000).
Too much alcohol can affect absorption of all foods, but especially vitamins and other
micronutrients through an effect on gastrointestinal motility and intestinal permeability
(Knight et al. 1992). Once again we encounter the importance of balance in the diet.
For example, some of the useful avonoids will not be available if essential vitamins
are absent. In turn there is a requirement to have enough fat in the diet if these vitamins
are to be utilised. An excess of one trace element can restrict the intake of another.
Alcohol may improve glucose tolerance (Baum-Baicker 1985a). It seems that alcohol
attenuates the increase in blood glucose concentration in subjects given a glucose load,
with an accompanying increase in the concentration of insulin in plasma (Facchini et
al. 1994). The implication is that alcohol increases the sensitivity of susceptible cells to
insulin. This in turn reduces demand on the pancreas. In a study of 735 ‘middle-aged’
British men, moderate drinkers (16–24 units per week) displayed a reduced risk of
developing non-insulin dependent diabetes (Perry et al. 1995).
Recently there have been some intriguing studies on the relationship between alcohol
consumption and the development of type II diabetes mellitus. This is the type of
diabetes that arises because the body does not make suf cient insulin and the system
does not work properly to control glucose levels, leading to hyperglycaemia. It was
formerly called ‘adult-onset diabetes’ and it accounts for 85–90% of diabetes in people
over the age of 30. The biggest risk is obesity.
Wannamethee et al. (2002) found that heavy drinkers run a greater risk of type II
diabetes. However, light and moderate drinkers did not run this risk. Stampfer et al.
(1988b) found a lower incidence of non-insulin dependent diabetes in moderate drinkers
(female nurses). Rimm et al. (1995) observed that moderate alcohol consumption
among healthy people might be associated with increased insulin sensitivity and a
reduced risk of diabetes. Moderate alcohol consumption may have a bene cial effect
on the risk of death due to coronary heart disease in those people displaying type II
diabetes (Valmadrid et al. 1999; Solomon et al. 2000). Tsumura et al. (1999) discovered
that among men with a body mass index of 22.1 or more, moderate alcohol consumption
was associated with a reduced risk of type II diabetes. However, among lean men
(BMI below 22.1), heavy alcohol consumption was associated with an increased risk
of type II diabetes.
If glucose accumulates through diabetic conditions then it is converted into sorbitol
by aldose reductase, the accumulating sorbitol leading to damage of tissues such as
eyes and kidneys. It has been shown that components of beer, including quercetin and
the iso-α-acids, inhibit aldose reductase (Shindo et al. 2002).
Alcohol enhances the absorption of glucose and galactose (Carreras et al. 1992).
There is little effect on fat absorption, provided there is an adequate intake of proteins.