Does Breastfeeding Protect Your Heart?

A study published in January in the Journal of the American Heart Association Report hints that breastfeeding might possibly protect mothers against diseases of the heart and blood vessels. The study is is a type of study that scientists call a meta-analysis and a systematic review of studies. This means that researchers searched for and reviewed a lot of scientific papers and selected some. From those selected papers, they then combined results from various studies published previously and did statistical analysis on certain aspects of all of those studies together. The advantage of this approach is that many more data can be evaluated to look for an answer to a question than can be evaluated for each individual study. This can reveal things that each smaller study did not reveal and even can reveal something that is the opposite of what one or more of the smaller studies seemed to conclude.

In the case of the meta-analysis mentioned above, researchers identified eight smaller studies already published. These studies all recorded whether women had nursed babies and also recorded various types of information on their cardiovascular health, such as whether they suffered myocardial infarction, strokes, and other conditions and death, and other factors relevant to their cardiovascular health, such whether they smoked, their diets, medications, and other diseases. As we have discussed in a previous post, the term infarction refers to the death of tissue in a particular region, due to the blood supply being inadequate in supplying the affected region with oxygen and other consumables. In the heart, most of the needed blood flow is to supply what’s called the myocardium. Thickest of the layers of tissue that form the heart, the myocardium consists of muscle cells, and a myocardial infarction is when there’s an infarction somewhere in the myocardium. An infarction also can occur in many other parts of the body, including the brain. This results in a stroke, although that’s just one category of stroke. Strokes also can occur from the process that’s kind of an opposite of infarction, namely a hemorrhage, which is bleeding. We have talked here on The Pulse about heart and brain problems occurring during pregnancy, but in this case we are talking about such conditions occurring much later in life. Combining the number of women from all eight studies, the number of women in the analysis of all the studies together was more than 1 million. The researchers performed a lot of mathematical analysis on the combined results of all of the studies.

The result of the mathematical analysis of the combined information suggested an association between breastfeeding and reduced risk of cardiovascular disease for the mother. While the result sounds good and suggests that if you breastfeed your babies your risk for heart disease and strokes would be lower than if you did not breastfeed, we must take the finding with a big grain of salt. That’s because the study also revealed wide variation among the content of the eight papers whose results were combined together. What this means is that there is a certain amount of apples to oranges comparison effects. Because of the smaller studies was conducted in the past with the intent for it to be a stand-alone piece of research, each one is different. The methods of the researchers were different, along with the various things that were measured. This means that the finding of a correlation between breastfeeding and reduced risk of cardiovascular conditions for the mother is a cautious conclusion and more research needs to be done.

Nevertheless, there are already many benefits to breastfeeding, both for the mother and for the baby. For the mother, it is already known that breastfeeding can reduce her risk of developing type 2 diabetes, breast cancer, and ovarian cancer. Breastfeeding also provides the newborn with IgA antibodies to help protect against infections, which is particularly important for the first six months of life, as the infant’s immune system ramps up. As for protecting yourself from cardiovascular disease, whether or not future studies confirm what the recent study suggests about the value of breastfeeding, there are other ways to minimize your heart disease risk. These include avoidance of smoking, dietary measures, such as a Mediterranean diet with a lot of fish, and exercising and maintaining a good weight.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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