Some 400 million people worldwide may be susceptible to
oxidative stress from foods with high oxidant levels such
as fava beans, and from smoking, a severe oxidative stress.
Upon eating fava beans or even inhaling fava pollen, they
can develop potentially fatal hemolytic anemia, called "favism."
Those afflicted develop jaundice and excrete blood in their
urine. Nearly 10 percent of those with such symptoms die.
Favism, a deficiency of the enzyme G6PD, results from a genetic
adapation to fight malaria.
have pinned the problem to various genetic variations, several
of which are common among southern Europeans, that appear
to have come about to help the body fight off malaria infection,
but which also make people react severely to oxidants such
as those in fava beans.
genetic mutations reduce the activity of the enzyme glucose-6-phosphate
1-dehydrogenase (G6PD), which is involved in regenerating
glutathione, an antioxidant.
mutations lower glutathione levels so that we can survive
but the malarial parasite cannot survive," Ames said.
"So it makes us more resistant to malaria, but at the
price of being on the borderline of antioxidant defenses."
meal of fava beans dumps the powerful oxidants vicine and
divicine into the body, overwhelming the antioxidants in
the blood and producing anemia.
searching the scientific literature, Ames and Elson-Schwab
found that one common mutation in the enzyme affects the
site where it binds with NADP (nicotinamide adenine dinucleotide
phosphate), a cofactor made from niacin, or vitamin B-3.
Those with favism may be able to supplement their diet with
niacin to avoid oxidative stress and hemolytic anemia that
can result from fava beans, smoking, and some drugs in areas
where malaria has been eliminated.
By Robert Sanders, Media Relations
may be useful treatment for many genetic diseases, or just
good way to tune up body's metabolism