How do I make sure my baby is getting enough iron?

Starting solids is an exciting time. You’re embarking on a new journey with your babe – watching them discover new sensations and cultivate new skills. Plus, watching babies eat spaghetti is incredibly adorable and entertaining. At the same time, feeding can stir up many insecurities for parents. Namely, worries about meeting their babe’s nutritional needs.

As you’ve likely heard from your pediatrician, iron is a priority nutrient for growing babes. It’s required to form healthy red blood cells which deliver oxygen throughout the body and iron deficiency in childhood has been linked to irreversible cognitive and motor deficits.

Babies accumulate iron in utero and store enough to last until the first 4-6 months of life. After which, their stores dwindle and they need to begin getting iron from their diet.

Amount of Iron in Breast Milk + Bioavailability

While formula is supplemented with iron, breast milk is very low in iron, containing just 0.3 mg/liter. This amount is not affected by mom’s diet, unlike some other micronutrients. 

Some point out that the bioavailability of iron in breast milk — the amount that is absorbed and able to be utilized by the body — is very high. This is somewhat true, but it doesn’t change the fact that breast milk is a poor source of iron.

While you’ll hear some people claim that iron in breast milk is 50% absorbable, one study (Domeloff, 2002) found that before 6 months, only about 16% of the iron in breast milk is absorbed. After 6 months, this increased to about 37% in unsupplemented, breast-fed babies but remained low (17%) in babies receiving supplemental iron. This is because iron absorption is affected by a few factors: the source of the iron (heme or non-heme), iron intake (how much iron one is consuming), and iron status (current status of iron stores and iron in the bloodstream).

Even if a baby was absorbing 50% of the iron in breast milk, and consuming 1 liter of milk a day, they’d only actually absorb 0.15 mg.

Here’s that math:

0.3 mg x (50% absorption rate) = 0.15 mg iron absorbed per liter of breast milk

Here’s where the conundrum occurs, the recommended daily allowance (RDA) of iron for babies from 6-12 months is 11 mg a day.

Yep, you read that right. It’s more than an adult male (RDA = 8 mg) requires.

In order to consume 11 mg a day of iron, an exclusively breastfed baby would have to eat about 13 ounces of beef or beans (both contain about 0.8 mg of iron/ounce). I don’t know about you, but we’ve never seen a 7-month-old take down that much food. And if you’re baby-led weaning, that complicates it even more, babies certainly aren’t gnawing off that much sirloin steak!

But before you run to the market to stockpile meat puree, let’s chat about the origins of this recommendation.

Why Is the RDA for Iron 11 mg/d for 6-12 Months?

RDAs are set at an amount that is two standard deviations above the estimated average requirement (EAR), which is the amount required to cover the needs of half of the population. An RDA, theoretically, should provide enough of the nutrient in question to meet the needs of 97-98% of the population.

In Europe, the DRV (the EU version of an RDA) for iron for 7-12 months was based on studies showing that 0.79 mg of iron per day is necessary to replace daily losses and increase red blood cell mass, tissue iron, and storage iron. From there, a “coefficient of variation” was set at 20% to account for babies whose needs are higher than the average, bringing the required amount of absorbable iron per day to about 1.1 mg.

But how do we get from a biological requirement of 1.1 mg to an RDA set at 11 mg? Bioavailability.

Bioavailability of Iron: Heme vs. Non-Heme

In setting the RDA and DRV, scientists assumed that the average bioavailability of iron in food sources would be about 10%. This is because most people worldwide are getting the majority of their iron from plant foods, which have a bioavailability ranging anywhere from 2-20% (Monsen, 1988).

Iron found in plants is known as “non-heme” iron, meaning it is not bound to hemoglobin, the oxygen-carrying molecule found in red blood cells. Non-heme iron is found alongside compounds in plants known as absorption inhibitors which prevent iron from being absorbed (Hurrell, 2010). These include phytic acid, polyphenols, and calcium.

Therefore, for babies to meet the physiological demand for iron, and factor in wiggle room to meet the needs of 97-98% of the population, the RDA was set to aim for 1.1 mg of absorbable iron, which equals 11 mg of iron, assuming a 10% absorption rate.

Here’s the math:

11 mg of non-heme iron consumed x (.10 absorption rate) = 1.1 mg absorbed

Heme iron, found only in animal foods, is much more bioavailable at about 15-35% (Monsen, 1988).

This means that if a baby was consuming exclusively heme iron, they wouldn’t need to eat as much to meet their needs.

Here’s the math:

4.4 mg of heme iron x (0.25 absorption rate) = 1.1 mg absorbed

Iron Absorption Enhancers and Inhibitors in Foods

As discussed, the bioavailability of iron varies widely in different foods depending on whether the iron is heme or non-heme and the presence of absorption inhibitors or enhancers.

Nutrients that have been shown to increase non-heme iron absorption include:

·  Vitamin C – found in foods like citrus, strawberries, raspberries, cauliflower, and potatoes. Studies have shown that vitamin C can counteract inhibitors like phytic acid and increase iron absorption by 3-6 times (Hallberg, 1989).  

·  Lactic acid, found in fermented foods

·  Meat

Nutrients that inhibit non-heme iron absorption include:

·  Phytic acid – found in grains, legumes, nuts, and seeds

·  Polyphenols – found in some fruits and vegetables

·  Calcium – found in dairy, fortified products, and cruciferous vegetables.

Theoretically, including vitamin C with iron-rich plant foods could bring the absorption rate ~10% up to that of the heme iron found in meat, roughly 30%. However, we don’t have conclusive data demonstrating the exact absorption rate of various plant foods, so even if we know that the absorption rate is increased by 3 times with vitamin C, we don’t know if we’re starting at a 2% or 10% absorption rate.

To further complicate things, the “food matrix” in which iron is consumed, meaning the other foods eaten at the same time, can impact the absorption rate.

Therefore, it’s impossible to calculate exactly how much iron your baby is absorbing from any single source or meal.

Iron Content of Common Foods

So now we know why the RDA was set so high, the next logical question is – how does a baby actually get 11 mg of non-heme iron per day (or 4.4 of heme)?

Here is the iron content in a standard serving of a few common baby foods:

• 1 oz lentils: 0.9 mg
• 1 oz beef: 08. mg
• 1 oz tofu: 0.8 mg
• 1 oz chicken: 0.4 mg
• 1 oz peas: 0.4 mg
• 1 oz brown rice: 0.2 mg
• 1 oz salmon: 0.1 mg

As you can see, even with the richest sources of iron, you’d still need A LOT to meet babies’ needs. For example, to obtain 4.4 mg of iron from beef alone, baby would have to consume 4-5 oz, which is pretty much unheard of.

For plant-based sources, like beans, babies would need to consume over 11 oz a day – an impossible feat.

Can Babies Meet Iron Needs Through Whole Foods Alone?

Due to the gap between babies’ high iron needs and the low iron content of whole foods, the experts who set the recent Dietary Guidelines for Americans recommendations for babies and toddlers from 0-24 months came to this conclusion (Dewey, 2021):

“It [is] not possible to meet the RDA without the inclusion of iron-fortified infant foods.”They went on further to suggest that while it would be easier to meet the RDA using animal-based foods, “Obtaining [the RDA] solely from beef, which has ∼1 mg Fe/100 g (81 kcal of “baby food” beef), would require consuming 440 g of beef (356 kcal), which is not feasible.”

Iron-Fortified Baby Cereal

So, what’s the answer? At this point in time, the same solution we’ve used to decrease rates of iron deficiency for the past 90 years: iron-fortified infant cereal.

While “baby cereal,” gets a bad rap, it’s actually an incredibly easy, economical, and evidence-based way to reduce the risk of iron deficiency in young children.

With about 5 mg of iron per 3 tablespoon serving, iron-fortified infant cereal is well tolerated and easy to incorporate into breastfed babies’ diets starting around 6 months old.

Even if you’re serving meat, the current expert recommendation is still to include about ½ oz of iron-fortified cereal a day in your baby’s diet to help meet their high needs.

Claims that the majority of babies can meet their needs by consuming red meat alone are not only inaccurate but also incredibly elitist. The vast majority of the population cannot afford to serve red meat multiple times a day (ethical, environmental, and religious considerations aside).*Iron-fortified cereal is not recommended for babies fed infant formula, however, as formula is already iron-fortified and too much iron can be equally detrimental to developing children (Dewey, 2021). 

Iron-Fortified Baby Cereal Options

We recommend an oat-based baby cereal as infant rice cereals have been shown to contain potentially harmful levels of the heavy metal arsenic. Many brands offer organic options if you prefer.

For families doing baby-led weaning, iron-fortified cereal can be offered via a self-feeding spoon, or incorporated into recipes like pancakes or muffins.

We like to combine baby cereal with breast milk or water and a squeeze of orange juice to add vitamin C. We also like to serve it alongside vitamin-C rich fruits like strawberries or raspberries to maximize iron absorption.

An Anthropological Perspective on Iron

We’d be remiss if we ended this article without addressing the elephant (or more likely mammoth) in the room.

If baby’s iron needs are so high and iron in breast milk is so low, where were babies getting iron throughout the course of history – before iron-fortified cereal was created?

The answer is unclear. There is very little research on the complementary feeding practices of infants throughout history, aside from records about breastfeeding.

Some experts have theorized that babies were able to meet needs through a combination of iron-rich animal foods (such as organ meat) and iron-rich wild plants that mothers “pre-masticated” (chewed up and fed to baby) (Dewey, 2013). It’s also possible that babies were born with higher stores to begin with due to mom’s iron-rich diets during pregnancy and delayed cord clamping.   

Does this mean you need to/should serve animal foods like our ancestors? Not necessarily.
Prehistoric populations didn’t have the same issues we have today related to high meat intake (chronic diseases, climate change, animal welfare). Additionally, the consumption of iron-rich animal foods, such as liver, carries other risks such as vitamin A toxicity and environmental toxins (Ali, 2020). Ironically, those who tend to promote eating liver over iron-fortified infant cereal because of arsenic claims, ignore the fact that liver has been shown to have higher levels than meat of heavy metals like cadmium, copper, zinc and yup, arsenic too (Peng, 2017).

The PBJ’s Bottom Line:

Ok, we know that was a lot. Try not to stress (easier said than done, we know).

While this article was packed with numbers, we actually encourage you to forget all of the calculations we presented here. Numbers aren’t the answer. They are often inaccurate, highly variable, and will only make you crazy. This post has numbers but they’re simply intended to inform the issue by providing a micro view of the topic.

Now, we want you to step back, and instead, focus on a few key takeaways:

1. Discuss with your physician whether your baby should receive an iron supplement from 4-6 months.
2. For exclusively breast-fed babies, offer iron-fortified cereal daily (about ½ an ounce) starting at 6 months. Iron-fortified cereal isn’t recommended for formula-fed babies as it could put them at risk for too much iron. 
3. For all babies, offer iron-rich foods at all meals and snacks.
4. Pair iron-rich foods with a good source of vitamin C to maximize iron absorption.
5. Have your baby’s iron levels routinely tested starting between 9-12 months, per your pediatrician.

References

1. AG Data Commons: Providing Central Access to USDA’s Open Research Data. Ag Data Commons | Providing Central Access to USDA’s Open Research Data. (n.d.). Retrieved November 23, 2021, from //data.nal.usda.gov/dataset/usda-national-nutrient-database-standard-reference-legacy-release/resource/4f058928-9185-4fbe-aac1-3609338f2f19
2. Ali, H. S., Almashhadany, D. A., & Khalid, H. S. (2020). Determination of heavy metals and selenium content in chicken liver at Erbil city, Iraq. Italian journal of food safety, 9(3), 8659. //doi.org/10.4081/ijfs.2020.8659. 
3. Dewey KG. The challenge of meeting nutrient needs of infants and young children during the period of complementary feeding: an evolutionary perspective. J Nutr. 2013 Dec;143(12):2050-4. doi: 10.3945/jn.113.182527. Epub 2013 Oct 16. PMID: 24132575; PMCID: PMC3827643.
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6. Magnus Domellöf, Bo Lönnerdal, Steven A Abrams, Olle Hernell, Iron absorption in breast-fed infants: effects of age, iron status, iron supplements, and complementary foods, The American Journal of Clinical Nutrition, Volume 76, Issue 1, July 2002, Pages 198–204, //doi.org/10.1093/ajcn/76.1.198
7. Monsen ER. Iron nutrition and absorption: dietary factors which impact iron bioavailability. J Am Diet Assoc. 1988 Jul;88(7):786-90. PMID: 3290310.
8. Peng, H., Hu, B., Liu, Q., Li, J., Li, X.-F., Zhang, H., & Le, X. C. (2017). Methylated phenylarsenical metabolites discovered in chicken liver. Angewandte Chemie, 129(24), 6877–6881. //doi.org/10.1002/ange.201700736 
9. Richard Hurrell, Ines Egli, Iron bioavailability and dietary reference values, The American Journal of Clinical Nutrition, Volume 91, Issue 5, May 2010, Pages 1461S–1467S, //doi.org/10.3945/ajcn.2010.28674F
10. Wikimedia Foundation. (2021, November 21). Pablum. Wikipedia. Retrieved November 24, 2021, from //en.wikipedia.org/wiki/Pablum.