THURSDAY, March 15 (HealthDay News) -- Consuming the toxic metal
cadmium in the foods you eat may raise your risk for breast cancer,
a new Swedish study suggests.
Cadmium, which is found in many farm fertilizers, can make its
way into soil and water, the researchers explained. Some of the
main sources of cadmium in the diet are bread and other cereals,
potatoes, root crops and vegetables. Once it enters the body,
cadmium may mimic the effects of the female hormone estrogen, which
can fuel the growth of certain breast cancers.
"Modern life has become increasingly dangerous for our breast health," said Dr. Marisa Weiss, director of breast radiation oncology and breast health outreach at Lankenau Medical Center in Wynnewood, Pa. "Now, there's cadmium hanging onto our carrots and whole grains, the very vegetables that are supposed to be good for us," she noted.
"To help our patients reduce their exposure to environmental chemicals (like cadmium), which might increase their risk for breast cancer, we have to partner with our farmers to make sure our foods are grown in healthy soil without chemically loaded fertilizers," said Weiss, who is also president and founder of Breastcancer.org. "Sticking to real, whole (unprocessed) foods remains a healthy strategy until we can be more sure of what's inside the package."
In the Swedish study, the researchers followed close to 56,000
women for more than 12 years. Women filled out food frequency
questionnaires, which the researchers used to estimate how much
cadmium they consumed in their diets. There were 2,112 breast
cancer diagnoses during the follow-up period, including 1,626
estrogen receptor-positive and 290 estrogen receptor-negative
Women who had the highest amount of cadmium in their diets were
21 percent more likely to develop breast cancer than women who had
the least amount of cadmium in their diets. This risk increased to
27 percent among women who were lean or normal-weight, the study
showed. The risk was similar, 23 percent, for both estrogen
receptor-positive and -negative tumors.
Those women who consumed higher amounts of whole grain and
vegetables had a lower risk of breast cancer compared to women
exposed to dietary cadmium through other foods.
"It's possible that this healthy diet to some extent can counteract the negative effect of cadmium, but our findings need to be confirmed with further studies," study author Agneta Akesson, an associate professor at Karolinska Institute in Sweden, said in a news release from the American Association for Cancer Research. "It is, however, important that the exposure to cadmium from all food is low."
The findings are published in the March 15 issue of
Johanna Lampe, a member of the public health sciences division
at Fred Hutchinson Cancer Research Center in Seattle, said the new
study adds to a growing body of research linking cadmium exposure
to breast cancer risk. "It adds another grain of sand to the pile,"
she said. "We would benefit from more research in this area to
understand these risks better."
The ideal study would use a more objective measure of cadmium
exposure, such as cadmium levels in urine. "We could look at women
years before they develop breast cancer and measure cadmium
exposure at certain points in time," she explained.
In terms of lowering exposure to cadmium, Lampe said that
smoking is the most important single source of cadmium exposure.
"Not smoking is a good place to start," she noted.
Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill
Hospital in New York City, said that it is too early to recommend
making any dietary changes based on these findings. "We can't say
we should limit intake of fiber and other things that contain
cadmium yet," and some of the foods that contain cadmium are part
of a healthy diet, Bernik stressed.
In the study, thinner women had a higher risk for breast cancer
based on their exposure to cadmium. "Obesity overrides any effect
that cadmium may have on breast cancer," Bernik said, adding that
obesity is a greater risk factor for breast cancer than cadmium
exposure, because "when people are overweight, they have more
estrogen circulating in the body."
Learn more about breast cancer risks and how to lower yours at