Praise the garlic! With each passing year, scientists discover new reasons
to consume large amounts of "Russian penicillin." High tech meets
folk wisdom in recent studies of garlic's chemical composition. Now we find
that garlic stimulates the production of an enzyme called glutathione S-transferase
(GST), which, naturally occurring in the body, protects against cancer by
detoxifying potent carcinogens.
S. C. Nair showed in 1991 that production of this enzyme could be stimulated
by the chemical diallyl sulfide found in garlic. Garlic may also protect
against aging. A cover story on aging in Scientific American (12/92) showed
that GST "help[s] to repair oxidized fatty acids."
The oxidation of fatty acids is involved in many disease processes, including
cancer. Science can be beautiful as well as fascinating. A computer image
of this same enzyme in the journal Biochemistry (10/27) reveals an avant-garde
sculpture of 434 amino acids arranged in matching twin sections. Cast in
metal, it would not be out of place in an outdoor sculpture garden.
On each section there is a kind of docking station, where a peptide stands
ready to deactivate toxins that wanders into the cell's neighborhood. An
amino acid trigger (tyrosine) is carried on the bigger molecule, just waiting
for a chance to activate glutathione whenever the toxin is sighted. Garlic
could even suggest story lines for Deep Space Nine.
Scientists have found that stimulating GST may guard against liver cancer,
which kills a quarter of a million people around the world every year. Dr.
John D. Groopman of Johns Hopkins reported that when rats fed a powerful
liver carcinogen were given a drug that stimulates this enzyme, none of
them developed liver cancer (Cancer Research, 1/15/92). But this drug approach
brings with it serious side effects, including DNA damage, whereas garlic
is, well, just garlic.
