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Breastfeeding May Reduce The Risk Of Type 2 Diabetes

Mom smiling at baby

Type 2 diabetes, also known as adult-onset or noninsulin-dependent diabetes, is a chronic condition that affects systemic glucose metabolism. With type 2 diabetes, one’s body either resists the effects of insulin (a hormone that regulates the movement of sugar into your cells),  or the body doesn't produce enough insulin to maintain a normal glucose level. Untreated, type 2 diabetes can be life threatening.

Type 2 diabetes mellitus affects about 9 million adult women in the United States. Several studies have suggested that breastfeeding may protect against type 2 diabetes.

One of these studies suggests that the duration of lactation is inversely associated with risk of type 2 diabetes in young and middle-aged women, and is independent of other diabetes risk factors including body mass index, diet, exercise, and smoking status.1

This study included two cohort groups, one group was of 83,585 parous women in the Nurses Health Study (NHS)(group 1) and another group was of 73,418 parous women in the Nurses’ Health Study II (NHS II)(group 2). Among parous women,an increased duration of lactation was associated with a reduced risk of type 2 diabetes.

For each additional year of lactation, women in group 1 with a birth in the prior 15 years had a 15% reduction in the risk of diabetes.  Women in group 2 had a 14% reduction in risk of diabetes.

Other studies have suggested how breastfeeding may protect against diabetes:

  1. One study suggests that breastfeeding imposes an increased metabolic burden on mothers, that included an increased energy requirement of approximately 480 kcal/d. This metabolic burden may be responsible for reduced blood glucose levels and thus a decreased risk of type 2 diabetes.2
  2. Both human studies and animal models have suggested an improved insulin sensitivity and glucose tolerance in mothers during lactation compared with non-lactating mothers who served as controls. These differences were independent of weight change.3,4,5
  3. Some studies have also suggested an increased weight loss among lactating mothers in the postpartum period. These findings suggest that maternal lactation may reduce future risk of type 2 diabetes.6,7
  4. A smaller study has assessed postpartum metabolic markers in 26 white women (14 lactating and 12 non-lactating) with gestational diabetes. At 3 months postpartum, there were no significant differences in insulin sensitivity, or amount of total visceral or subcutaneous fat. The lactating group had more efficient pancreatic B-cell function, increasing insulin levels and thus a stable blood glucose level.8
  5. Another study suggests that lactation may affect insulin and glucose homeostasis. The researchers studied glucose tolerance in 809 Latina women previously diagnosed as having gestational diabetes. In follow-up testing at 4 to 12 weeks postpartum, lactation was associated with improved glucose tolerance, lower fasting glucose levels, and lower total area under the glucose tolerance curve.

Thus, there are many studies now, which suggest that breastfeeding may reduce the risk of type 2 diabetes in breastfeeding mothers.


Sonia Shoukat  M.D.

Thomas W. Hale Ph.D.



This data is summarized and produced by the staff at the InfantRisk Center at Texas Tech University School of Medicine. Dr. Thomas Hale is the Director of this Center.

If you have questions concerning the use of drugs, chemicals, radioactive substances, or diseases in pregnant or breastfeeding mothers we invite you to call the InfantRisk Center at 806-352-2519.


  1. Alison M. Stuebe, MD; Janet W. Rich-Edwards, ScD; Walter C. Willett, MD, DrPH; JoAnn E. Manson, MD, DrPH; Karin B. Michels, ScD, PhD Duration of Lactation and Incidence of Type 2 Diabetes. JAMA. 2005;294(20):2601-2610. doi:10.1001/jama.294.20.2601.
  2. Butte NF, Wong WW, Hopkinson JM. Energy requirements of lactating women derived from doubly labeled water and milk energy output.  J Nutr. 2001;13153-58.
  3. Kjos SL, Henry O, Lee RM, Buchanan TA, Mishell DR Jr. The effect of lactation on glucose and lipid metabolism in women with recent gestational diabetes.  Obstet Gynecol. 1993;82451-455.
  4. Burnol AF, Leturque A, Ferre P, Kande J, Girard J. Increased insulin sensitivity and responsiveness during lactation in rats.  Am J Physiol. 1986;251E537-E54.
  5. Jones RG, Ilic V, Williamson DH. Physiological significance of altered insulin metabolism in the conscious rat during lactation.  Biochem J. 1984;220455-460.
  6. Brewer MM, Bates MR, Vannoy LP. Postpartum changes in maternal weight and body fat depots in lactating vs nonlactating women.  Am J Clin Nutr. 1989;49259-265.
  7. Butte NF, Hopkinson JM. Body composition changes during lactation are highly variable among women.  J Nutr. 1998;128(2 suppl)  381S-385S.
  8. McManus RM, Cunningham I, Watson A, Harker L, Finegood DT. Beta-cell function and visceral fat in lactating women with a history of gestational diabetes. Metabolism. 2001;50715-719.
  9. Kjos SL, Henry O, Lee RM, Buchanan TA, Mishell DR Jr. The effect of lactation on glucose and lipid metabolism in women with recent gestational diabetes. Obstet Gynecol. 1993;82451-455.