November 22, 2005

Breastfeeding may reduce mothers’ diabetes risk

By Graciela Flores

NEW YORK (Reuters Health) - Women who breastfeed longer
have a lower risk of developing type 2 diabetes, new research

"Various studies suggest that breastfeeding affects women's
metabolism, and that prompted us to look at whether lactation
does something in terms of diabetes risk," Dr. Alison M. Stuebe
of Brigham and Women's Hospital and Harvard Medical School in
Boston told Reuters Health. "Those studies show that
metabolism, lactation, and reproduction are all tied together
in a potentially interesting way."

To look for associations between lactation duration and the
development of type 2 diabetes, Stuebe and her colleagues
analyzed data from two large groups of women who had given
birth. The first group included 83,585 women who were part of
the Nurses' Health Study, and the second group included 73,418
women who were part of the Nurses' Health Study II. "The second
group is a younger group," said Stuebe.

The researchers found that in the first 15 years after a
woman's last delivery, each year of breastfeeding was
associated with a 15-percent reduction in her risk of diabetes.
"In that analysis, we took into account diet, exercise, smoking
status, whether or not the women took multivitamins -- which is
a marker of whether they are health-conscious or not -- and we
still found that 15-percent benefit," remarked Stuebe.

"Beyond 15 years after the last birth there wasn't so much
of a benefit, but for at least the first 15 years there seems
to be some long-term association that protects women from
diabetes," she added.

"In some way, pregnancy is a pro-diabetic state; you have
more resistance to insulin, and that's part of the way the body
makes sure that the fetus gets enough sugar," explained Stuebe.
"Then comes lactation which, in a sense, is an anti-diabetic

The researchers' hypothesis is that lactation resets the
body after pregnancy. If a woman does not breastfeed for a
prolonged period of time, the risk of diabetes might increase.

For Stuebe, one of the nicest things about these findings
is that there is no downside to breastfeeding. "It gives us
more reasons to encourage women to breastfeed: it's good for
babies and it's good for mothers," she concluded.

SOURCE: The Journal of the American Medical Association,
November 23/30, 2005.