Mothers, and not just babies, may have much to gain from breastfeeding. Breast milk is considered an ideal source of nourishment for an infant, but two recent studies suggest it protects women from a particularly vicious type of breast cancer.
One study found that breastfeeding reduced the risk of hormone receptor negative tumors, a very aggressive type of breast cancer, by up to 20 percent. Even a brief period of breastfeeding reduced the risk of these hard-to-treat tumors, which are more common in African-Americans and younger women, according to researchers.
The other study suggests that breast-feeding may act like a “reset” button for metabolism after pregnancy — helping women who had gestational diabetes avoid becoming lifelong diabetics.
Breastfeeding Health Advantages
These recent findings go together with earlier research showing that women who breastfeed have a lower risk for Type 2 diabetes, rheumatoid arthritis, breast and ovarian cancers. Additionally, breastfeeding may also help cardiovascular health, including a healthy blood pressure.
Dr. Eleanor Bimla Schwarz, a professor of medicine at the University of California, Davis said this new research is a great benefit for women.
“This is a win-win — it’s good for the baby, too. For all the women who want to do something to reduce breast cancer, this is doable. We need to make sure that’s part of the debate.”
Dr. Schwarz cited earlier research showing that near-universal breastfeeding in the United States could spare an estimated 5,000 women a breast cancer diagnosis every year and cut nearly 14,000 heart attacks.
The recent report on the effects of breastfeeding on breast cancer analyzed dozens of previous studies, in addition to nearly 40,000 cancer cases from around the world. The results of the study were published last month in Annals of Oncology.
Dr. Marisa Weiss, the paper’s senior author, said that pregnancy and lactation are important steps on the breast’s decades-long path to maturation. She added that lactation triggers changes in milk duct cells that make the breast more resistant to cancer.
“The breast gland is immature and unable to do its job, which is to make milk until it goes through the bat mitzvah of a full-term pregnancy. Breast-feeding forces the breasts to finally grow up and get a job, and make milk, and show up for work every day and every night, and stop fooling around.”
However, the lactation physiological changes go beyond the female breast. Some scientists are referring to breastfeeding as the “fourth trimester” of pregnancy that completes the reproductive cycle, restoring a woman’s body to long-term cardiac and metabolic health.
Breastfeeding and Diabetes
In addition, women who develop pregnancy-related diabetes, and those who are at seven times the normal risk of developing diabetes after pregnancy, are encouraged to breastfeed because lactation improves glucose metabolism and insulin sensitivity. Breastfeeding also burns calories, improves lipid metabolism, and mobilizes the stores of fat that have mounted up during pregnancy.
According to the study’s findings, mothers who breast-fed for more than 10 months cut their risk of a diabetes diagnosis by almost 60 percent in the two years they were followed. Of the 205 women who only breast-fed and used no formula for the first two months of the baby’s life, 17 women developed diabetes, compared with 27 women of the 153 mothers who did not breast-feed and only used formula. The study was published Monday in Annals of Internal Medicine.
The study’s lead author and a senior research scientist at Kaiser Permanente Northern California, Dr. Erica P. Gunderson said during lactation, glucose levels are lower, and there is less demand for women who breast-feed.
“Pregnancy is a metabolic challenge. One of the possible biologic explanations is that this gives the woman’s pancreatic beta cells a bit of a break, allowing for recovery from the demands of pregnancy.”