So far, there isn’t much evidence from human studies that those chemicals matter. That’s what the Institute of Medicine found in its 2011 report, Breast Cancer and the Environment: A Life Course Approach, which was commissioned by Susan G. Komen for the Cure.
“I am not a fan of pesticides in food or chemicals in the environment that we now find ubiquitously in human tissues,” says David Hunter, the Vincent L. Gregory professor in cancer prevention at the Harvard School of Public Health.
“We definitely can’t give them a pass. But the evidence of an association with breast cancer in humans is very limited, so a lot depends on how confident you are extrapolating from test-tube and animal data to give advice to people.”
And it has gotten tougher to gather data in humans.
“Increasingly, there is evidence that childhood and adolescent and young adulthood exposure is important,” says Hunter, who served on the panel of experts who wrote the IOM report.
“We’ve made it even more difficult to gather human evidence by pointing the exposure window back to many decades prior to the cancer diagnosis. Nobody’s got a 50-year prospective study.”
Of course, it’s sensible to avoid potentially harmful chemicals anyway.
“If women are worried about their children, and it’s possible to avoid exposure to pesticides and plasticizers without greatly altering one’s lifestyle, I would say, why not?” says Hunter.
“That may have other health benefits that have nothing to do with breast cancer,” he adds. “But we can’t pretend that we know for certain that that’s going to reduce a child’s breast cancer risk later in life. It’s just very, very hard to establish cause and effect, particularly with cancer, when you may be looking at a 40- or 50-year exposure.”
Source: iom.edu/Reports/2011/Breast-Cancer-and-the- Environment-A-Life-Course-Approach.aspx.
Other relevant links:
• The latest on uncertain links between diet and breast cancer. See: How to Diet to Prevent Breast Cancer
• Weight loss and breast cancer. See: Does Diet and Weight Loss Affect Your Risk of Breast Cancer?
• Does Alcohol increase your risk of breast cancer? See: What Not to Eat: Alcohol and Breast Cancer