I recently interviewed Dr.Shannon Kelleher, a human milk researcher, about the staggering results from her recent publication “Biological underpinnings of breastfeeding challenges: the role of genetics, diet, and environment on lactation physiology,” published recently in the American Journal of Physiology-Endocrinology and Metabolism. Dr. Kelleher’s mission is to use scientific and statistical research to uncover how lactation works, why it can fail, and how diet affects a woman’s ability to produce enough quality milk. In Part I, we talked about lactation statistics, and zinc. Today, in Part II, we discuss colostrum and genetics:
Shannon L Kelleher, PhD is an Associate Professor in Nutritional Sciences, Surgery and Cell and Molecular Physiology at the Penn State Hershey Cancer Institute. She holds a PhD in Nutritional Biochemistry/Cell Biology from The University of California, Davis, and a B.A. in Biology/Chemistry from the University of San Diego.
Jody: You mention in your study that mothers produce only a small volume of colostrum (about 30ml/24 hours) and that colostrum’s primary role is meant to boost immunity. At that small amount, I know that a baby would not be fully fed metabolically. So how can colostrum help prevent starvation in the first 2 days of life?
Dr. Kelleher: That’s an excellent question. It’s not entirely known. Although colostrum is believed to be primarily immunological in nature, it does contain a lot of key nutrients that babies need. For example, it has more protein and zinc than mature milk but less fat and lactose, so it is a rich source of nutrients, hormones, and bioactive factors required by the newborn. However, colostrum alone is not meeting the needs of many infants who are suffering from unintended starvation.
Jody: When a mother cannot provide the required amount of breast milk to nourish her baby, it is commonly described as insufficient glandular tissue development. Your paper explores the genetics behind this. Can you explain how it’s related to insufficient milk production?
Dr. Kelleher: Insufficient glandular tissue, or IGT, is an important contributor to overt lactation failure, and estimates are that about 10% of women suffer from it. It’s also known as “breast hypoplasia.” In our paper we propose that there are more subtle issues that lead to poor lactation, such as genetic differences in the molecules that regulate lactation.
Jody: Is there anything we can do about those genetic differences other than identifying them as a cause of insufficient milk supply?
Dr. Kelleher: I hope that someday we will be able to use genetic counseling and novel diagnostic tools to identify women who are struggling with breast milk supply and support them. I’m really looking forward to our two new studies (currently underway), where we are just starting that focus on the genetics of low milk volume, and identifying biomarkers in breast milk that can predict low milk volume. Because once we identify these genetic variants that cause poor lactation, and understand how they interfere with it, I see at least two pathways forward:
- Understanding the genetics would help us to identify these women BEFORE they struggle with insufficient milk supply. Then, they could receive appropriate education and support BEFORE a baby becomes ill.
- Understanding how genetic variants interfere with lactation would motivate the development of medications that could improve lactation outcomes, beyond domperidone (which is banned in the US) or metoclopramide, or nutraceutical therapies.
Jody: How do genetics determine milk composition?
Dr. Kelleher: Well, we are beginning to identify genetic variants in milk proteins, but we don’t yet understand if these differences are important to infant health.
Jody: What supplements are good for a lactating mother to be sure her milk contains optimal nutrients?
Dr. Kelleher: Though there’s no conclusive answers, studies have shown that the effect of maternal supplements on infant health (primarily immune function and asthma) has to do with the mother’s DNA makeup.
Jody: In your paper you state breast milk clearly provides optimal nutrition for the growing infant as long as the mother is capable of producing an adequate volume of high quality milk. Understanding what mothers can and can’t do to improve their lactation can help them learn how to best protect and feed their newborns. Is it fair to say there is a significant genetic component that is responsible for insufficient milk supply?
Dr. Kelleher: Is it fair to say we really don’t know why a mother (especially a first time lactating mother) is at much greater risk for insufficient milk production? Yes, I believe that genetics are an important factor, but as a science we are just beginning to start asking these kind of questions and it is much too early to say anything more definitive.
Jody: What can clinical providers do to support patients with suboptimal lactation?
Dr. Kelleher: The most “easily” modifiable factor is diet and exercise. I would suggest a balanced diet that is very rich in antioxidants (both our mouse and human studies have implicated oxidative stress as a major player in dysfunction), combined with daily exercise, just even taking a walk for 30 minutes each day. …..and sleep! The laundry and dirty dishes can wait.