Oxytocin is produced by the posterior pituatary gland in the brain. This hormone is best known for its role in promoting uterine contractions during childbirth but it is also involved in sexual arousal and orgasm, thus the label, “love hormone.” Oxytocin is also important for social behaviors such as trust, contentment, empathy, bonding, and love. Without it we would have a pretty dull and detached life. Recently, researchers found yet another extremely important biological activity of oxytocin–it helps estrogen keep our bones strong and healthy.

Development of the fetus during pregnancy places substantial nutrient demands on a woman. Normally, estrogen levels increase during the 9 months of pregnancy. This helps to preserve bone by promoting an increase in calcium uptake from the gut and by stimulating osteoblastic bone-building activity in the skeleton. After delivery, estrogen levels return to normal and the heightened calcium loss through mother’s milk during breastfeeding can severely stress skeletal calcium reserves. However, if the mother is consuming adequate calcium, bone density will typically recover within several months. A study from the Mount Sinai Bone Program at the Mount Sinai School of Medicine in New York shows us how.

Colaianni et al. (2012) found, through studies with mice, that the bone-building action of estrogen occurs, in part, through oxytocin produced by osteoblasts in bone marrow. This, they concluded, is the mechanism that facilitates “rapid skeletal recovery during the latter phases of lactation.”

During childbirth there is a huge surge of oxytocin released into the mother’s blood stream by the pituatary. This stimulates uterine contractions to facilitate the birth. Once the baby is delivered and begins to breast feed, this stimulation promotes oxytocin release, an important mechanism for aiding uterine postpartum recovery.

Nipple stimulation and oxytocin release throughout breastfeeding not only supports bonding behavior * between mother and baby but also helps the mother regain bone density. In a study by Karen L Pearce at the University of Massachusetts (2006), 35 women were assessed for the effect breastfeeding has on bone density. What Pearce found was that “greater intensity of breastfeeding in the amenorrheic months significantly attenuated bone density loss ” and that “women who breastfed with less intensity showed greater decline in their bone mineral density.”

Oxytocin is clearly extremely important for bone health and it does not stop when child bearing years are over. This love hormone can help maintain bone density throughout your life…all it takes is a little bit of love, and nipple stimulation. 

* Note: For more information on the health benefits of breastfeeding check out La Leche League International. This is a great organization. Their mission is to promote a better understanding of breastfeeding as an important element in the healthy development of the baby and mother.

Colaianni et al. 2012. Bone marrow oxytocin mediates the anabolic action of estrogen on the skeleton. Journal of Biological Chemistry 287(34):29159-67.

Pearce, L. Karen. 2006. Breastfeeding and bone density change. Electronic Doctoral Dissertations for UMass Amherst. Paper AAI3215777.