Updated: Mar 11, 2020
Is breast milk really low in iron? Why would my milk be deficient in such an important nutrient? Does my exclusively breastfed baby need iron supplements? Do I really have to start my baby on iron fortified cereal at 4 months? How do I prevent my breastfed baby from becoming iron deficient? And how do I serve meat doing baby led weaning method?
As a breastfeeding mom, I'm sure you've asked yourself these or similar questions. I'm glad you do - iron is an important nutrient to keep in mind for breastfed babies. I'm glad you ask questions and do your research rather than relying on hearsay or outdated information - as there is a lot of misinformation circulating on the internet, and not all health professionals are up-to-date either.
Iron is extremely important for your baby's development, not just because it transports oxygen to every cell of their body (including the brain), but also because an iron deficiency increases the absorption of toxic metals which can harm baby's neurological development even further.
And it's true: Breast milk is low in iron! But why? Why would such an important mineral be low in breast milk? You've probably guessed that Mother Nature intended for it to be that way - breast milk is low in iron for a few good reasons. In this article, let me explain to you why breast milk is low in iron, and what you can do to prevent an iron deficiency in your breastfed baby anyway.
Iron is one of the most important nutrients for Babies!
Iron, with its chemical symbol Fe (Ferrum), is considered an essential mineral in human nutrition. It is present in many foods, but most importantly, a part of hemoglobin, the protein in red blood cells which carries oxygen to all of our cells. Not enough iron can lead to a condition called iron deficiency anemia, which means there are not enough healthy red blood cells to send oxygen to our cells. Our cells essentially become oxygen deprived, and that is bad news. Early symptoms of an iron deficiency are fatigue, weakness and a weakened immune system.
In babies, an iron deficiency can present as follows: They may sleep excessively long, they may nurse less often or have a poor appetite, they may drop off of their respective growth curve and not meet their milestones. Last but not least, they may easily catch a cold and be sick 'all the time' (source). If your baby starts showing any of these symptoms, it's best to take them to the pediatrician to get their iron levels checked because an iron deficiency can have long-lasting detrimental effects on neurodevelopment if left untreated. Down the road, it can affect their emotional stability, learning ability, memory function and more.
Iron-deficiency isn’t just a problem in itself. Iron shares similar absorption mechanisms with some neurotoxic metals such as Lead, Manganese and Cadmium. If there isn’t enough iron (i.e. if mom or baby are iron deficient), it can increase the concentration of these toxins in breast milk and/or baby's blood (source). So, it's important for baby AND mom to not be iron deficient.
“Even though iron deficiency in a breastfeeding mother does not affect the iron levels in her milk, she should make sure she is getting enough iron in her own diet not only to replenish iron stores lost at childbirth, but also because iron deficiency can lead to the accumulation of neurotoxic metals in her breast milk.”
Let's face it: It is important to avoid an iron deficiency, especially in our babies and small children, but also for mom.
Breast milk low in iron
It's true what you've heard, breast milk is very low in iron - it contains only around 0.2 to 0.4 milligrams of iron per 29 fluid ounces (860 milliliter).
It's also true that iron absorption from breast milk is higher than from other sources. It lies somewhere around to 16% to 49% (sources 1, 2, 3). However, this excellent absorption doesn't make up for the fact that there simply isn't much there. Even if 100% of the iron from breast milk was absorbed into baby's blood, it would only meet about 2 to 4% of baby's daily iron needs.
Iron is also one of the few nutrients which is NOT affected by mom's intake while breastfeeding. That means, you will not be able to increase the amount of iron in your breast milk by eating iron rich foods or taking iron supplements (see here and here). Iron is transported across the mammary epithelial cells in the breast via an active transporter, which acts as a type of gate guard, allowing a fixed amount of molecules in at a time, regardless of how much iron you currently have in your blood.
Why is breast milk low in iron?
You may ask yourself, why would mother nature make breast milk low in iron. There must be a reason. Well, there are actually three reasons:
First, most healthy, full-term babies are born with large iron stores. These stores are acquired mainly during the last weeks of pregnancy and can supply your baby with enough iron to last them for the first 6 months or so. It gets a little tricky if your baby was born prematurely (<36 weeks gestation), experienced blood loss at birth or you were iron deficient during your pregnancy. In that case, it is possible your baby needs an iron supplement or iron rich foods before 6 months of age! (a quick iron check at your pediatrician's office around 4 months of age should give you peace of mind)
Here's a tip: Discuss leaving the umbilical cord attached for a few minutes after birth with your health care provider, instead of cutting it right away, since blood (and iron) will continue to reach your baby until it stops pulsating, setting them up for more iron stores.
The second reason breast milk is low in iron is that too much iron is not necessarily a good thing, especially for newborns.
Too much iron can lead to an increased settlement of bad bacteria in the gut (see here, here and here). Breast milk being low in iron essentially lowers your baby's risk to become infected with e.coli and other pathogens and builds a healthier microflora in baby's gut. It may actually be one of the reasons why formula fed babies' microflora differs significantly from that of a breastfed baby.
Another study I found hypothesized that excessive dietary iron intake by infants could hyper stimulate the immune system and be the root cause of autism, allergies and other childhood diseases (source). More research is certainly needed in these areas, considering the high amount of iron in some infant formulas.
The third reason (I believe) breast milk is low in iron is that it gives the breastfeeding mother a chance to replenish her own iron stores. Pregnancy and childbirth deplete a mother’s iron stores significantly. Before she can safely carry another child, these stores must be recovered. Most women who exclusively breastfeed for the first months will experience “lactational amenorrhea”, the temporary cessation of the menstrual cycle. During this time, and because the ‘loss’ of iron through breast milk is low, breastfeeding mothers can (and need to!) recover their iron stores if their dietary intake is adequate.
How to Keep my Breastfed Baby From Becoming Iron Deficient?
First of all, I do not recommend iron supplements in breastfed babies unless absolutely necessary. That is because absorption from these supplements is usually very low. The unabsorbed iron ends up in baby's gut, messing with the formation of a healthy gut flora (which is so critical at this stage, and will determine the risk for so many future diseases for years to come). I do NOT recommend iron supplementation for breastfed babies proactively. Have your pediatrician or WIC office check baby's iron levels, ideally at 4 months or sooner.
Most infants develop an interest in solid foods around 6 months of age. This is just about the time when iron stores endowed at birth start to run out. Because iron is so critical for baby's development, I recommend to introduce iron-rich foods around 6 months of age to a breastfed baby in order to prevent an iron deficiency.
I do not recommend 'waiting' to introduce iron rich solid foods much beyond 6 months of age, unless you have baby's iron stores checked regularly.
Meal Planning Tips to prevent iron deficiency
The best sources of iron by far are organ meats like chicken, pork and beef liver. Liver contains around 10 to 15 milligrams of well absorbed heme-bound iron per 3 ounce serving, so you'll easily be able to meet the recommended intake of 11 milligrams per day (after 6 months of age). And yes, you can give liver to your baby! It doesn't have to be every day, or 3 ounces at a time. A little here and there, added or mixed in with other foods, will do the trick!
Baby Led Weaning Tip: Add finely chopped liver to homemade meatballs or similar ground meat dishes and serve it to your baby once or twice per week, or offer some liverwurst or liver pâté (on a cracker) on occasion.
Meats are, of course, a more conventional source of iron. Although they contain less iron than organ meats, their iron is also well absorbed and can contribute greatly to meeting baby's iron needs. A 3-ounce serving of beef stew (cooked) contains around 2.5 milligrams of iron, ground beef around 1.7 milligrams per 3 ounces; a 3 ounce serving of pork tenderloin (cooked) contains around 1 milligram of iron, whereas chicken breast contains the least, around 0.3 milligrams per 3 ounces.
Baby Led Weaning Tip: Serve meat in the form of meat balls, ground beef or very slow cooked meat that falls apart easily. You can also let baby gnaw on a near meatless chicken drumstick (baby can suck and gnaw the last little bit of meat and meat juices off the bone). Note that chewy pieces of meat such as steak or chicken breast are not suitable for baby led weaning as they are a choking risk.
Non-heme bound iron sources can also contribute smaller amounts to your baby’s daily iron needs, although its absorption is less efficient as iron comes in the form of non-heme bound Fe2+. Examples of good plant-based iron sources are spinach, lentils, beans (kidney, white), tofu, molasses and cocoa powder.
Dairy products such as milk, yogurt and cheeses decrease iron absorption and should therefore be served separately from your plant-based iron source. Phytate, an indigestible substance found in hulls of nuts, seeds, beans and whole grains can also hinder iron absorption. It is not necessary or recommended to avoid these foods (they supply the body with important nutrients!). Try to serve them separately from your plant-based iron food or reduce the phytate content by soaking, sprouting, fermenting or cooking your beans and grains.
Do not give your child cow’s milk until at least 12 months of age. Cow’s milk has adverse effects on iron nutrition in infants for several reasons. First of all, it is not a good source of iron. It is, however, high in calcium and casein, both of which inhibit dietary non-heme iron absorption. Additionally, about 40% of infants experience occult intestinal blood loss from cow’s milk, diminishing iron stores even further (this generally ceases after one year of age). If you would like to supplement breast milk with another ‘milk’, choose human donor milk or formula instead. Small amounts of cheese and yogurt are generally considered safe after 8 months of age, and milk can be introduced in small amounts after 1 year of age.
Maximize iron absorption with Vitamin C: Luckily, there is also a factor which increases iron absorption! Vitamin C in the form of freshly squeezed lemon or orange juice is an easy and delicious way to get the most out of your plant-based iron source.
Maximize iron absorption with Breast milk! Yes, breast milk has also shown to increase non-heme iron absorption!
Use cast iron cookware: For hundreds of years, cast iron pans have been used for cooking over the hearth or fireplace. With recent controversies surrounding some chemicals in modern cookware, this ancient cookware has resurfaced as a popular way to cook and bake. As a positive side effect for those with iron deficiency, bare cast iron leaches small amounts of iron into the food during the cooking process. Some foods with high acidity and moisture, cooked for an extended period of time (Spaghetti sauce, for example) can potentially increase in iron more than tenfold!