Biomedical Engineering Reference
In-Depth Information
humans exposed to large doses of methanol is also discussed. The early
history of methanol toxicity is reviewed demonstrating the role of
occupational overexposure, both inhalation and dermal, as the major
cause of methanol toxicity in humans. Ingestion overdose has been
reported more frequently in the later twentieth century and now is the
primary cause of methanol toxicity in humans. A section is also devoted
to treatment and management of methanol poisoning, but the treatment
of an individual with methanol poisoning is an individual issue and
should be left to the treating physician.
3.2 EXPOSURE
3.2.1 Dietary
The most important source of background body burdens of methanol is
dietary. Methanol is found at low levels in alcoholic beverages. Beer
ranges from 6 to 27mg/l and wine 96 to 329mg/l while the level of
methanol in neutral sprits have been reported to be as high as 1500mg/l
(CERHR, 2003). A Swedish study reported a correlation with blood
ethanol and blood methanol following ingestion of alcoholic beverages
(Jones and Lowinger, 1988).
Methanol in diet is found in the normal human diet in natural fresh
fruits and vegetables, where it occurs as the free alcohol, methyl esters
of fatty acids, or as methoxyl groups on pectin (Henze et al., 1953;
Francot and Geoffroy, 1956; Meigh, 1957; Sommer, 1962; Casey et al.,
1963; Anonymous, 1997). The average concentration of methanol in
fruit juices has been estimated to be 140mg/l of juice with a range of
12-620mg/l (Francot and Geoffroy, 1956). Eating about 500 g of fruit
resulted in methanol concentration in the breath equal to drinking
100ml of brandy containing 24% ethanol and 0.19%methanol (Taucher
et al., 1995).
Aspartame is a dipeptide with a sweetening power of 180-200 times
that of table sugar (Cloninger and Baldwin, 1970). It has been widely
used in beverages as a sweetening agent. During the absorption and
metabolism of aspartame, methanol is released. Methanol makes up
10% of the aspartame molecule. Normal aspartame ingestion has been
