Insulin impacts each stage of Milk Production – Implications for Insulin Resistance
The hormone insulin, best known for its role in blood glucose regulation, plays a major role in milk production. It helps prepare the mammary glands for lactation during pregnancy, supports the transition from colostrum to milk after birth, and works in concert with other hormones to meet both the mother’s and infant’s nutritional needs throughout the nursing period.
During pregnancy, in collaboration with hormones such as estrogen, progesterone, and prolactin, insulin develops the readiness of the specialized cells within the mammary gland that are responsible for producing milk. A newer study from 2021 suggests that insulin’s role during pregnancy is key: the researchers discovered that without insulin, mammary tissue does in fact form, yet it fails to produce milk.
After childbirth, the mammary gland cells become more sensitive to insulin, prompting the pancreas to produce more of the hormone. Insulin then triggers the synthesis and secretion of milk. It also influences the composition of breast milk by directing the uptake of fatty acids and proteins. As well, insulin plays an indirect role in converting blood glucose into lactose, the primary sugar in breast milk. Lactose serves as a vital “osmotic agent,” drawing water and electrolytes into the milk and increasing its volume.
Around two weeks after childbirth, insulin levels decrease. At this juncture, mammary glandular tissue is so sensitive to insulin that it requires less to achieve the same effects.
Insulin and Prolactin: A Hormonious Friendship
Prolactin is the primary hormone for milk production. It acts on the mammary gland tissue to increase milk production. In the days after childbirth, prolactin also has another role: it tells the pancreas to increase its number of insulin-producing cells, resulting in an increase of insulin.
Insulin reciprocates by increasing the mammary gland tissue’s sensitivity to prolactin. Thus, these two hormones create a harmonious feedback loop that optimizes milk production.
Insulin resistance occurs when the body’s cells become less responsive to insulin. Given insulin’s roles in preparing the mammary gland during pregnancy, initiating milk production post-birth, and maintaining milk supply, it’s understandable why those with insulin resistance may face challenges in building and maintaining their milk supply.
Insulin resistance is often accompanied by low-level systemic inflammation, suboptimal hydration, and elevated estrogen levels. Each of these can impede milk production, and the latter can shorten the duration of lactational amenorrhea — the absence of ovulation and menstruation while nursing.
Mothers with insulin resistance may need to consume more calories or even gain weight to maintain their milk supply. This again has to do with the body’s delayed and compromised response to insulin.
The stress that mothers experience while working through milk production problems can lead to heightened cortisol levels, which again can affect milk production.
How the Lactogenic Diet and Lifestyle can Help
The Lactogenic Diet offers a holistic approach. It utilizes dietary and lifestyle strategies that increase insulin sensitivity, reduce inflammation, improve hydration, and reduce and manage stress. We call these actions the Four Pillars of a Lactogenic Diet and Lifestyle.
Who has Insulin Resistance?
Insulin resistance may be found in those of us who easily gain weight, are overweight and obese, who have a hormonal imbalance called Polycystic Ovarian Syndrome (PCOS), or a hormonal imbalance called Metabolic Syndrome. It is present in women who are diagnosed as being at risk of gestational diabetes, or who have pre-diabetes or type II diabetes. As of a recent survey, 10% of women in the United States are at risk for gestational diabetes.
Worldwide, rates of obesity and diabetes have been steadily increasing since the early 1970s. It is projected that by 2030, 30 – 50% of the world’s population will have pre-diabetes or diabetes type II.
Clearly, in our present time and increasingly in the future, pregnant and breastfeeding mothers will be dealing with insulin resistance and require extra help and guidance.
What lies ahead for Breastfeeding Mothers?
For mothers who plan to nurse their babies, the worldwide increase in insulin resistance means that specialized interventions are needed to support their best efforts.
My own low milk supply was linked to Insulin Resistance, Polycystic Ovarian Syndrome, and Insufficient Glandular Tissue (IGT). I overcame my imbalances and produced a full supply after researching and utilizing the Lactogenic Diet.
Get Professional Help
Many lactation specialists understand insulin resistance and its complications. They can help you and your healthcare provider settle on a helpful combination of galactagogues, dietary adjustments, medications, and exercise; often, this combination quickly improves insulin sensitivity and helps to improve your milk supply.
In addition, you can include lactogenic ingredients in your meals, snacks and beverages (see my Lactogenic Foods and Herbs Handouts). These ingredients are considered safe. However, always talk to your doctor about changes in diet or the use of supplements if you are taking medication. In particular, lactogenic ingredients can have interactions with blood-thinning or blood-sugar lowering medications.
- Learn more about the balance of hormones after childbirth: The Postpartum Dance of Estrogen, Insulin, and Cortisol for Milk Production.
- Learn about how the body can lose its sensitivity to insulin: Insulin Resistance: when the body's energy management falters.
- Learn more about causes of low supply that respond to dietary changes here: Causes of Low Milk Supply that respond to Lactogenic Foods and Herbs
- Learn how insulin builds the mammary gland tissue and supports milk production: Insulin impacts each stage of Milk Production – Implications for Insulin Resistance
Hi! I'm Hilary Jacobson, and I've been helping moms with milk supply issues for over 30 years. My book, 'Mother Food,' was a game-changer when it first came out, and I'm still at it—researching, writing, and teaching to make sure new moms get the support they need. Want to stay in the loop? Sign up to my newsletter for updates.
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Sadovnikova, A., Garcia, S. C., & Hovey, R. C. (2021). A comparative review of the cell biology, biochemistry, and genetics of lactose synthesis. Journal of Mammary Gland Biology and Neoplasia, 26(2), 181-196.
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