While the benefits of breastfeeding for babies have been well-studied, two recent studies show that mothers who nurse also receive a health boost. The first study found that breastfeeding, even for a brief period of time, reduced the risk of a very aggressive and difficult-to-treat type of breast cancer tumor by up to 20%. Hormone receptor negative tumors are more common in African-American women and young women. The study, which was published in Annals of Oncology, outlined how pregnancy and lactation help the maturation of the breast, triggering changes to make it more resistant to cancer. The second study examined the effect of breastfeeding on the development of diabetes in women who had previously developed gestational diabetes. Breastfeeding, which helps regulate metabolism and burns calories, was found to reduce the risk of developing Type 2 diabetes by half in these women, who are at seven times the normal risk of developing diabetes after pregnancy. The study found that the risk for developing Type 2 diabetes was lowered even more the longer the women breastfed. Previous research has also linked breastfeeding with lower risks of other breast and ovarian cancers as well as rheumatoid arthritis.