Childhood Factors Increase Breast Cancer Risk
Search for Breast Cancer Risks Uncovers Early-Life Clues
Growth, Nutrition, and Breast Cancer Risk
The central clue here, Michels says, is that early, fast growth during childhood increases breast cancer risk.
To interpret this finding, Michels turns to data from Japan. The current generation of Japanese women grew much faster than their parents did. They have a much higher rate of breast cancer than their parents do, too. The difference between the generations isn't genetic. It's dietary. Younger Japanese women grew up on diets with much more meat and dairy products than previous generations of Japanese women.
"What are the predictors of rapid growth in childhood? They are probably dietary," Michels says. "And if you look at kids with rapid growth between the ages of 8 and 18, and compare them with those who don't grow fast, my interpretation is there is probably a difference in diet."
Look at the growing epidemic of obesity in children, Michels says. Something is wrong.
"We have to rethink the diet of our children and whether we are doing them a favor by the diet they are getting," she says. "There is no particular advantage to fast growth. So maybe there is an opportunity for breast cancer prevention with a change in diet."
Chemical messengers called growth factors tell the body when to grow. Red meats and dairy products, Michels says, are full of growth factors -- and they stimulate the body to release its own growth factors.
"These growth factors, we know, are associated with cancer," Michels says. "Growth means more rapid cell division, and more rapid cell division means more chance for mutations and higher risk of cancer."
At least until researchers tease out a better way to prevent breast cancer, Michels recommends a diet abundant in fruits, vegetables, and whole grains -- particularly for children.
"Cancer is not something that develops just in one or five years but is a process underway for many, many years," Melbye says. "Different factors all have to be in there to eventually lead to breast cancer. So we should focus our research on these very early growth patterns."