Updated: Mar 11
I'm writing this to clear something up. In fact, it's the main reason I started this blog in the first place:
Yes, your diet affects the composition of your breast milk. What you eat - the fats, proteins, vitamins, minerals, phytonutrients...all of it is ultimately turned into breast milk. It's basically what breast milk is made of: the food you eat. (No, it's not made from pixie dust and sunshine. Well, maybe sunshine, a little, in the form of Vitamin D...)
Sure, there's more to it. Your milk is not made up of undigested chunks of banana or spinach stemming directly from your stomach. There's digestion, and absorption, and transport through the blood; possibly conversion and ultimately, there's Lactogenesis. But in the end, the building blocks of breast milk stem from your diet, because what's in your diet ends up in your blood, and that blood reaches your mammary tissue and delivers the 'goods'.
I know, I know... you've been told breast milk is ideal for babies. Even women living in food poverty can breastfeed. You've been told breast milk is all a baby needs for the first 6 months or so.
All of this is still correct!
But there's so much more to the story. So much more you may not have been told by your doctor, your nurse or your lactation consultant, likely because they did not want to scare you away from breastfeeding. They did not want you to think you have to have the perfect diet to breastfeed. (I understand this way of thinking, but unfortunately, it completely ignores the science!)
Let me be clear: You don't have to have the perfect diet while breastfeeding! Breast milk is the best food for your baby, even if your diet is less than optimal (with few exceptions, of course). But knowing how your diet affects your breast milk; knowing which foods to include to boost very specific nutrients in your breast milk critical for your baby's development, and ultimately better meeting your recommended intake levels for all vitamins and minerals so that you or your baby don't become deficient (because the recommended intake for many nutrients is even higher while breastfeeding than during pregnancy!) is an enormous opportunity! (Trust me, you'll never have this much control over your child's diet again!)
Not just because it will ultimately benefit your baby, but also because it can help you heal postpartum, it can help you regain your energy, help you achieve a healthy weight and so much more!
You just can't ever go wrong with a healthy diet, and that is especially true during pregnancy and while breastfeeding.
Let me show you why I've made it my career goal as a Dietitian and Lactation Counselor to show you that #nutritionmatterswhilebreastfeeding
Breast is best, even if mom's diet is less than optimal. But let me introduce you to a different way of looking at it:
You can optimize your breast milk through diet!
Let me give you a few examples:
Daily supplementation of a breastfeeding mother’s diet with 6400 IU (International Units) Vitamin D provided breast milk concentrations which were enough to meet the infant’s Vitamin D requirements (1).
Supplementation with DHA, an omega-3 fatty acid important for brain development in infants, significantly altered the fatty acid composition of the mother’s breast milk (2). Many lactation consultants now recommend weekly fish consumption to their nursing mothers.
In a group of breastfeeding women who developed mastitis, women assigned to receive probiotics improved more and had lower recurrence of mastitis than those assigned to the antibiotic group (3).
Nutrition matters while breastfeeding! – Tweaking our diets may actually improve our breastfeeding experience and our children’s health and development!
Then, there is the other side of the medallion - and I'm not going to withhold it: Some dietary practices can actually negatively influence our breast milk.
An exclusively breastfed infant to a vegan mother was hospitalized for an enlarged liver and spleen and a significant delay in reaching milestones. He was diagnosed as having a Vitamin B12 and Iron deficiency due to the mother’s diet (4).
A healthy, non-diabetic woman was hospitalized with nausea and vomiting. She had developed ketoacidosis (usually only seen in diabetics) because she was following a low carbohydrate, high fat diet while breastfeeding (5).
The fact of the matter is – important nutrients in breast milk are indeed influenced by the mother’s diet.
Selenium and Iodine are examples. Each of them necessary for normal thyroid function for mom and baby. Many breastfeeding moms are not consuming enough of these important nutrients. Not surprising, since the recommended intake for Selenium and Iodine is even higher while Breastfeeding than during pregnancy (6)!
There are some good food sources of selenium - Brazil nuts, fish/seafood, liver and sunflower seeds. Iodine can be found in seaweed, fish and milk products. Are you eating these foods regularly? If not, let's chat about how to include these foods into your diet regularly, or possibly add an appropriate supplement.
Your intakes of the B Vitamins (B1, B2, B3, B6, B12), as well as Vitamins A, D, E, K and choline also influence the concentration of these nutrients in your breast milk; each involved in many different metabolic processes, from brain development to energy metabolism. Some studies suggest the Fluoride content of human milk may directly be related to the extent of fluoridation of the local drinking water.
Let me give you another example: Breast infections are a common, painful occurrence among breastfeeding moms. If you’ve ever experienced one, you know just how painful it is. All too often, mom stops breastfeeding due to the pain or because her milk production dwindles. Could taking a daily probiotic or eating foods such as Tempeh, Sauerkraut and probiotic yogurts lead to a quicker recovery, or even prevent such infections?
The fatty acid composition of your breast milk is also highly variable and dependent on the quality of fat in your diet. Are you eating cold water fish like salmon and sardines at least once a week? No? Because you're afraid of mercury exposure? Choosing your fish and portion sizes wisely can optimize your baby's intake of brain boosting fatty acids and other nutrients, while keeping mercury levels minimal.
“Milk is successfully produced by mothers regardless of their nutritional status. Nevertheless, the concentrations of some nutrients, specifically vitamins A, D, B1, B2, B3, B6, and B12, fatty acids, and iodine, in human milk depend on or are influenced by maternal diet.” – Valentine et al.
Then there are those nutrients in breast milk which are not influenced by the mother’s diet. Examples are Calcium, Iron, Zinc, Copper and Folate. To protect the infant from a deficiency (or overload!), these nutrients are filtered through an active transport mechanism into the mother’s milk, where other factors, such as stage of lactation, determine its content. This does not mean these nutrients aren’t important in a breastfeeding mother’s diet! The opposite is the case: While the nursling appears to be shielded from maternal malnutrition in these cases, mother’s stores could become depleted!
Most diets are compatible with breastfeeding. However, it is absolutely crucial to be aware of certain nutrients lacking in some diets (such as vegan or ketogenic diets), and ways to supplement those while breastfeeding.
You don’t have to eat the perfect diet
Even if your diet is less than perfect – breast milk remains the gold standard for infant nutrition. Its dynamics to change the concentration of nutrients and hormones during and between feeding, its cancer fighting cells (yes, you heard right! Breast milk can actually kill cancer cells), its antibodies specific to the type of infection baby is exposed to, its calming effect on the nursling, and the many properties that are still undiscovered make breast milk far superior to any other form of nutrition for infants!
And no, breast milk does not turn into ‘junk food’, simply because you ate that burger or slice of pizza. The breast produces milk using nutrients from your blood stream; some nutrients are even produced in the alveoli itself. The end result is nutritious breast milk – the best food for your baby – even if you don’t eat the perfect diet.
However, the fact that our diet influences the composition of breast milk actually gives you the opportunity to positively impact your child’s health for years to come. Research suggests these benefits can last a lifetime, and may even be passed down to the next generation! That's right...by tweaking your diet during pregnancy and while breastfeeding, you can potentially improve your child's visual, cognitive and psychomotor development, as well as reduce your child's (and grandchild's!) risk for chronic disease and obesity. Now that's amazing!
Please consider sharing this article to get the word out. Unfortunately, talking about how nutrition affects our breast milk is still taboo among the breastfeeding community, but it completely ignores the science and robs us of the opportunity to do even better for our children!