Chemistry Reference
In-Depth Information
Other industrial processes commonly used by the food industry, such as irradia-
tion, ionization, microwaving, smoking, also significantly contribute to increased
production of AGEs/ALEs. No foods seem to be excluded; industrial treatment of
plant products (roasting, drying, “curing”) will contribute to increased amounts of
AGEs/ALEs in foods to the same extent as animal products. Fresh tobacco leaves,
fresh coffee beans, fresh peanuts are extremely rich in powerful antioxidants, which
totally disappear during the industrial process (“curing,” roasting) and are replaced
by larger amounts of AGEs/ALEs. As the temperature increases above 100°C, car-
cinogens, especially heterocyclic amines, are also produced, a production that also
increases dramatically with higher temperatures.
AGEs/ALEs do not reach the body exclusively through the food we eat; these
compounds are also produced spontaneously in the body, especially with elevated
levels of sugars and fatty acids in body fluids and tissues. Accumulation in the body
of late Maillard products—AGEs/ALEs—is generally regarded as irreversible; what
is accumulated will stay more or less forever. The observation that these substances
are found in larger amount has commonly been regarded as an expression of normal
aging. However, it might not be so. Instead, it might depend mainly on lifestyle and
thus in theory be preventable. Large to extreme increases in content of AGEs/ALEs
are regularly observed in body fluids and tissues of patients with chronic diseases,
particularly in diabetes and chronic renal diseases, especially so in those suffering
complications such as patients with diabetes with reduced wound healing,
2
neph-
ropat hy,
3
and angiopathy.
4,5
Advanced accumulation of AGEs/ALEs in tissues often
occurs as amyloid,
6
fibrillary tangles,
6,7
or similar deposits. Such structures were
long regarded as degenerative but biologically inert structures. However, increas-
ing evidence supports the conclusion that these structures are foci with very strong
proinflammatory potential, capable of maintaining chronic inflammation at high
level in the tissues.
7.3 INTroDuCTIoN oF MolECulAr bIology
ChANgED ThE vIEW oF AgEs/AlEs
Early on, Maillard had suggested that accumulation in the body of AGEs/ALEs
could significantly contribute to progression in diseases, such as diabetes and some
chronic urogenital diseases, especially uremia. He created what he called “index of
urogenital imperfection,” which he used to document an association between degree
of accumulation in the body of Maillard products and severity of disease, especially
chronic renal disease. However, the time was not yet ripe for such thinking and the
concept was rejected by scientists and clinicians of that time and would remain so
for several decades. With the introduction of modern molecular biology and par-
ticularly so with the identification of specific receptors in the body for these sub-
stances, human medicine became more seriously interested. Although identification
by American Ann Marie Schmidt in 1992 of a specific receptor for AGEs/ALEs
(RAGE) seems to be the turning point,
8-11
it is only in the last few years that a wider
interest in the concept has developed. Since the year 2000, several international
