Cadmium Exposure May Boost Breast Cancer Risk

Cadmium can find its way into the diet via fruits and vegetables grown in soils fertilized with products containing the toxic metal. In the body, cadmium may mimic the effects of estrogen, raising the risk for certain breast cancers.

Swedish researchers followed about 56,000 women for more than 12 years, monitoring their diet by questionnaires to find out how much cadmium they were consuming.

During that period, 2,112 women were diagnosed with breast cancer, including 1,626 who had breast cancer sensitive to estrogen, called estrogen-receptor positive cancer, and 290 who had nonestrogen-sensitive breast cancer, called estrogen-receptor negative.

Cadmium's Impact

Women with the highest amount of cadmium in their diet were 21 percent more likely to develop breast cancer than women with the least amount of cadmium. In women who were thin or of normal weight, the risk increased to 27 percent.

Women who ate more whole grains and vegetables had a lower risk for breast cancer compared with women who got their cadmium through other foods. The researchers speculate that the healthier diet rich in whole grains and vegetables may have counteracted the effects of cadmium, but they said more research was needed to confirm this.

Watching what you eat

Marisa Weiss, M.D., at Lankenau Medical Center in Wynnewood, Pa., says the study points to the need for more vigilance when choosing healthy foods. "Now, there's cadmium hanging onto our carrots and whole grains, the very vegetables that are supposed to be good for us," she says.

"We have to partner with our farmers to make sure our foods are grown in healthy soil without chemically loaded fertilizers," she adds. "Sticking to real, whole [unprocessed] foods remains a healthy strategy until we can be more sure of what's inside the package."

But Johanna Lampe, Ph.D., at the Fred Hutchinson Cancer Research Center in Seattle, says that smoking is the most important single source of cadmium exposure.

"Not smoking is a good place to start," she says.

The study was published in the journal Cancer Research.

Always talk with your health care provider to find out more information.