August 5, 2013
Nursing Moms May Prevent Alzheimer’s Disease Through Breastfeeding
Brett Smith for redOrbit.com - Your Universe Online
What began as a modest pilot study has resulted in a striking new finding surrounding the development of Alzheimer's disease.
The study authors said their findings were only preliminary for now, citing the small study cohort along with a lesser connection among participants who had a family history of dementia. However, they said their results begged further investigation and strengthened the case for breastfeeding, which is already known to convey a host of benefits to both mother and child.
Nursing has been found to restore insulin tolerance in mothers, which is significantly reduced during pregnancy, and Alzheimer's has been linked to insulin resistance in the brain. The scientists said their findings could open up new avenues for researching both causes and cures for the debilitating disease.
"Alzheimer's is the world's most common cognitive disorder and it already affects 35.6 million people," said co-author Molly Fox, a biological anthropologist at the University of Cambridge. "In the future, we expect it to spread most in low and middle-income countries. So it is vital that we develop low-cost, large-scale strategies to protect people against this devastating disease."
In the study, the research team surveyed 81 British women with and without Alzheimer's between the ages of 70 and 100 regarding their history with respect to reproduction, breastfeeding, general physical health and mental health. The UK-based scientists also talked to the women's relatives, spouses and caregivers.
To measure dementia status, the research team used a standard rating scale called the Clinical Dementia Rating (CDR). They calculated participants' onset of dementia using the CDR as a foundation and factoring in age and known patterns of Alzheimer's progression. These calculations were compared with the participants' breastfeeding history.
Even without considering confounding factors such as age of first childbirth or drinking history, the study results indicated an unmistakable connection between nursing and lowered Alzheimer's risk. The team also found that a longer breastfeeding history was associated with a lowered Alzheimer's risk and participants who had a higher ratio of total months pregnant to total months breastfeeding had a higher Alzheimer's risk.
In a statement, the study authors said their results could have something to do with the hormone progesterone, which is produced during pregnancy and deprived during breastfeeding. Progesterone is known to desensitize the brain to estrogen, which is suspected to protect the brain against Alzheimer's. They also speculated that nursing restores a woman's insulin sensitivity after pregnancy and Alzheimer's is linked to insulin resistance in the brain. In fact, the disease in often casually referred to as "Type 3 diabetes."
"Women who spent more time pregnant without a compensatory phase of breastfeeding therefore may have more impaired glucose tolerance, which is consistent with our observation that those women have an increased risk of Alzheimer's disease," Fox added.