Madison, WI, February 2,
2009 - As the world seeks new ways to prevent and treat chronic
diseases such as diabetes, heart disease and cancer, more research
continues to be conducted on the benefits of certain foods in reducing
people’s risk of contracting these ailments. Legumes in particular are
often cited as being high in antioxidants, which have the property of
being able to fight off free radical cells within the body, reducing
the risk of cancer and other chronic diseases. A recent study further
investigated these connections, as researchers focused on the benefits
of one type of legume, dry beans, in reducing the risk of mammary
cancer.
To address whether dry bean consumption is associated
with a reduction in mammary cancer, scientists at Colorado State
University studied the anticancer activity of six market classes of
bean including; small red, great northern, navy, black, dark red and
white kidney bean in the diet of laboratory animals. They also
evaluated whether the level of antioxidants or seed coat pigments in
the bean were related to mammary cancer. The study was funded by a
grant from the Beans for Health Alliance, and the Colorado Agricultural
Experiment Station with assistance from Archer Daniels Midland Co. and
Bush Brothers Inc. Results from
the study were published in the January-February 2009 issue of the journal
Crop Science.
Cooked dry bean powder from the six market
classes and a control group without beans in the diet were fed to
laboratory rats in a standard preclinical model for breast cancer. The
dry bean powders were also evaluated for antioxidant capacity, phenolic
and flavonoid content; all factors thought to be associated with
anticancer activity. Chemical analysis of the beans
revealed that total phenolic and flavonoid content varied widely among
market classes and the differences were strongly associated with seed
coat color; where colored beans had ten times or greater phenolic and
flavonoid content compared to white beans.
Antioxidant
capacity of the beans also varied widely among dry bean market classes
and were highly related to seed coat color, where colored beans had
approximately two to three times greater antioxidant capacity than
white beans.
Dry bean consumption from every
market class reduced cancer incidence (number of animals with one
tumor) and tumor number per animal compared to the control group.
Cancer incidence was reduced from 95% in the control group to 67% in
animals fed beans. The average number of malignant tumors was also
reduced from 3.2 in the control group to 1.4 tumors per animal in the
group fed bean. N
o associations were observed
between phenolic content, flavonoid content and antioxidant capacity
with cancer among the bean market classes. These results clearly
suggest that the anticancer activity in dry bean is not associated with
seed color or antioxidant capacity.
Research
is ongoing at Colorado State University to investigate the mechanisms
and molecules that contribute to the anticancer properties of dry bean.
Clinical trials are also underway to determine if bean in the diet of
humans are associated with biomarkers for cancer incidence.