The
idea came from a recently published study conducted in three
West Side ZIP codes — 78207, 78228 and 78237 — where liver
cancer rates are high.
That study found nearly 12 percent of residents tested had
aflatoxin, a toxic mold that grows on corn, peanuts and
other grains, in their urine.
That percentage — and the amounts of aflatoxin — isn't as
high as in some developing countries, where the toxin is
common and liver cancer rates are very high. But health
officials said it is worrisome, particularly in combination
with other risk factors.
Now those same researchers at the Metropolitan Health
District and Texas A&M University are preparing a new,
three-year study of the same neighborhoods, hoping to learn
whether changes in diet and a clay-based dietary supplement
can reduce that risk.
“I see this as a food safety project,” said Kyle Cunningham,
manager of Metro Health's Center for Environmental Health.
“Our food in the United States is extremely safe. But
aflatoxin is a very potent carcinogen. And in a population
where other factors are at play, I think aflatoxin exposure
probably would bring up the rates of liver cancer.
Those other factors include hepatitis C, a leading cause of
liver cancer in this country. Seven percent of the residents
in the earlier study were infected with the virus. Other
causes of liver cancer include diabetes, alcohol use and
chemical exposures.
Some residents have pointed to the latter, arguing that
pollutants from the shuttered Kelley AFB seeped into a
shallow aquifer over the decades and exposed residents.
Experts have tried to assure residents there's no link, but
many are unconvinced.
“Our ultimate goal is to try and bring down the high rates
of liver cancer that we see on the West Side of San
Antonio,” Cunningham said. “Aflatoxin is a very potent
carcinogen, especially when there are other factors involved
— such as hepatitis. And we found quite a bit of
hepatitis C..”
Of the 184 residents that took part in the earlier study,
those with aflatoxin in the blood also reported eating
higher amounts of corn, rice and peanut products.
Clay additives are already used in some animal feeds to
reduce aflatoxin exposure. Timothy Phillips, chairman of
toxicology and an expert in aflatoxin at A&M, has developed
a similar additive for human use. The specially formulated
clay supplement binds to aflatoxin in the digestive system.
The researchers hope to recruit 500 residents for the new
study. The City Council is expected to consider Metro
Health's accepting $334,540 as a share of grant funds for
the project today.
High rates of liver cancer aren't limited to the West Side.
All of Bexar County suffers from one of the highest rates of
liver cancer — and liver cancer deaths — in the state.
Between 2004 and 2008, Bexar led all other large counties
with 13.7 cases per 100,000 population, well above No. 2
Harris at 9.3. It also led in liver cancer deaths at 10.9
per 100,000, again followed by Harris at 7.4.
