RAW or COOKED
FOODS
Tiến sĩ Bùi Quốc Quang
Recently the consumption of raw seafood (sushi, sashimi,
etc.) has been raised due to the possible presence of heavy metals (methyl
mercury, lead, etc.,) and parasites. Should we eat only cooked food? I’m
not convinced.
The Maillard reaction is responsible for the formation of browning products
contributing to color, odor and taste of grilled (thịt nướng, thịt BBQ,
v.v) and/or processed foods (nước mầu kho thịt cá, v.v.). Browing reaction
products from mainly glucose and aspargine are responsible for the formation
of acrylamide (AA) in foods (Ho CT, 2006). The presence of AA in foods
causes considerable concern since AA is classified as probably carcinogenic
to humans by the International Agency for Research on Cancer (IARC, 1994)
AA is readily absorbed and metabolized in the human body. A metabolic
pathway is the CYP2E1 (cytochrome P450 2E1) dependent oxidation of AA
leading to the formation of the genotoxic epoxide glycidamide (GA)(Sumner
et al., 1999). GA reacts with DNA and other macro-molecules forming adducts
(GA-adducts) and this is probably the main pathway responsible for the
carcinogenic effect of AA (Dearfield et al., 1995). A major detoxification
pathway is glutathione conjugation resulting in urinary excretion of a
mercapturic acid derivative (MA-AA). This deactivation pathway therefore
competes with the formation of GA adducts. The above kinetics are not
unique to AA. Indeed, a large number of chemical carcinogens are biotransformed
to more toxic metabolites by phase I activation enzymes, such as CYP2E1
or to non-toxic compounds by phase II enzymes, such as glutathione-S-transferase.
CYP2E1 is an inducible enzyme found mainly in the liver, but is also found
in significant levels in other human tissues. The role of CYP2E1 in epoxidation
of AA to GA and formation of GA-adducts has been demonstrated and ascertained.
Whether or not AA can induce cancer in an individual depends on two factors.
The individual variations in the dietary intake of AA and the genetic
polymorphisms affecting enzymes involved in biotransformation are the
two most important determinants of the individual susceptibility to chemical
carcinogens. Depletion of the glutathione through the chronic use of certain
medications may also contribute to the overall risk of individual for
AA-associated disease such as neurotoxicity and cancer.
One thing for sure is that raw seafood is not associated with cancer whereas
grilled food may be. So, in my opinion, the best way to balance our diet
and gene-interaction is to enjoy a combination of seafood and products
of Maillard reaction such as cá nướng, cá kho tộ, tôm càng nướng, sò huyết
nướng lò, v.v. Ăn ngon quên chết. Quên chết thì ngán gì cancer với ba
thứ parasites vớ vẩn.
Until the next time, stay healthy.
Buiquốc Quang
April 2009
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2009. Muốn phổ biến bài viết này, cần xin phép tác giả và xin ghi rõ nguồn
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