CONTACT: L. E. OHMAN
283 Medical Laboratories
Iowa City IA 52242
(319) 335-6660; fax (319) 335-8034
UI professor: Food additive may have breast cancer-causing properties
IOWA CITY, Iowa -- Lambda-carrageenan, a food additive widely used in
milk products such as infant formula, pudding, ice cream and whipped cream,
may have cancer-inducing properties.
A form of lambda-carrageenan has been shown to cause intestinal cancer
and ulceration in animals. In addition, the food additive has been shown
to cause the kind of changes in intestinal cells that lead to malignant
tumors. These facts made University of Iowa College of Medicine researcher
Dr. Joanne Tobacman wonder if the additive also affected breast cells in
a way that might lead to cancer.
In the laboratory, Tobacman, assistant professor of internal medicine,
examined the effect of the food additive on mammary myoepithelial cells
she grew in tissue culture. She found that lambda-carrageenan exposure
caused destruction of the cells and eventual cell death. This finding was
reported in the July issue of the journal Cancer Research.
One of the most important points of her study, Tobacman says, is that
lambda-carrageenan caused myoepithelial cell death at concentrations far
below those normally found in food products. The finding is potentially
"The mammary myoepithelial cells form a barrier between the blood
supply and epithelial cells. Compromise of this barrier may lead to the
development of malignant or invasive tumors," Tobacman says.
In fact, most malignant tumors arise from epithelial cells, and myoepithelial
cell absence is used as one criterion for the diagnosis of an invasive
Do these findings mean that lambda-carrageenan, which has been on the
market since 1937, is a cancer-causing food additive?
"We can't say that, yet," Tobacman says. "We have taken
one step forward and found an interesting association. Having new territory
to explore with regard to environmental agents that may be "smoking
guns" with regard to breast cancer is good news to cancer epidemiologists
who have been looking for an environmental etiology for breast cancer."
Tobacman would like to find out more precisely how lambda-carrageenan
affects the breast myoepithelial cells. She is seeking funding for further
studies and would like to bolster the laboratory findings with epidemiological
evidence, though it is difficult to quantify the intake of carrageenan.
She and other investigators are reviewing the diet questionnaires filled
out in 1986 by more than 50,000 women involved in the Iowa Women's Health
Study, in order to obtain more information about carrageenan intake.