A new Kaiser Permanente study has unveiled that women who have been diagnosed with breast cancer and have breast feed their babies have reduced risk of the disease recurrence. The study published in the Journal of the National Cancer Institute has found that these women actually had a 30% overall decreased risk.

In the study, there were 1,636 women with breast cancer. They completed a questionnaire having questions with regard to breastfeeding history. The researchers took additional medical data from medical chart reviews and Kaiser Permanente HealthConnectr, which is an electronic health record.

Study's lead researcher Marilyn L. Kwan, PhD, research scientist with the Kaiser Permanente Division of Research, said, "This is the first study we're aware of that examined the role of breastfeeding history in cancer recurrence, and by tumor subtype".

The researchers said that the benefits of breastfeeding were among women who were diagnosed with the luminal A subtype of breast cancer. However, they did not notice any associations for other subtypes.

Luminal A tumors include the estrogen-receptor positive breast tumors and they are the most commonly diagnosed of all breast cancers. Another thing noticed by the researchers was that women who had breastfed their babies had 28% reduced risk to die from the disease.

Kwan affirmed that breastfeeding may set a molecular environment that makes the tumor more responsive to anti-estrogen therapy. Bette J. Caan, senior research scientist with the Kaiser Permanente Division of Research, was of the view that breastfeeding make ductal cells in the breast less susceptible to carcinogens and also, lead to slower growing tumors.

It is a known fact that breastfeeding is great for babies. Now, researches are showing that it is also beneficial for mothers. The researchers said that the protection was even more for women who had a history of breastfeeding for six months or more.