The findings, published in the journal Evolution, Medicine and Public Health, suggest that breastfeeding may have a positive impact on postmenopausal women's cognitive performance and could have long-term benefits for the mother's brain.
"While many studies have found that breastfeeding improves a child's long-term health and well-being, our study is one of very few that has looked at the long-term health effects for women who had breastfed their babies," said Molly Fox, Ph.D., lead author of the study and an Assistant Professor in the UCLA Department of Anthropology and the Department of Psychiatry and Biobehavioral Sciences.
"Our findings, which show superior cognitive performance among women over 50 who had breastfed, suggest that breastfeeding may be 'neuroprotective' later in life," Molly added.
Cognitive health is critical for wellbeing in aging adults. Yet, when cognition becomes impaired after the age of 50, it can be a strong predictor of Alzheimer's Disease (AD), the leading form of dementia and cause of disability among the elderly - with women comprising nearly two-thirds of Americans living with the disease.
Many studies also show that phases of a woman's reproductive life history, such as menstruation, pregnancy, breastfeeding, and menopause can be linked to a higher or lower risk for developing various health conditions like depression or breast cancer, yet few studies have examined breastfeeding and its impact on women's long-term cognition.
Of those that have, there has been conflicting evidence as to whether breastfeeding might be linked to better cognitive performance or Alzheimer's risk among post-menopausal women.
"What we do know is that there is a positive correlation between breastfeeding and a lower risk of other diseases such as type-2 diabetes and heart disease and that these conditions are strongly connected to a higher risk for AD," said Helen Lavretsky, MD, the senior author of the study and a professor in the Department of Psychiatry and Biobehavioral Sciences at the Semel Institute for Neuroscience and Human Behavior at UCLA.
"Because breastfeeding has also been found to help regulate stress, promote infant bonding and lower the risk of postpartum depression, which suggest acute neurocognitive benefits for the mother, we suspected that it could also be associated with long-term superior cognitive performance for the mother as well," added Dr. Fox.
To find out, the researchers analyzed data collected from women participating in two cross-sectional randomized controlled 12-week clinical trials at UCLA Health: 1) The "Brain Connectivity and Response to Tai Chi in Geriatric Depression and Cognitive Decline," included depressed participants. 2) The "Reducing Risk forAlzheimer's Disease in High-Risk Women through Yoga or Memory Training that included non-depressed participants with some subjective memory complaints and risk for heart disease.
Among the two trials, 115 women chose to participate, with 64 identified as depressed and 51 non-depressed. All participants completed a comprehensive battery of psychological tests measuring learning, delayed recall, executive functioning, and processing speed.