Lactoferrin in Breast Milk

All About Lactoferrin In Breast Milk
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Lactoferrin is a protein found in the human body that attaches to iron. Certain body fluids including tears, saliva, urine, gastric fluid, and breast milk contain lactoferrin.

What Does Lactoferrin Do?

Lactoferrin has many functions. Its main role is to bind with and transport iron in the body. But, another important function is to fight off the germs that cause bacterial, viral, fungal, and parasitic infections.

Since some types of bacteria need to iron to grow and thrive, lactoferrin can prevent the growth of these bacteria by attaching itself to the extra iron in the body and preventing it from feeding the bad bacteria. Preventing the growth of these organisms helps to prevent infections.

Lactoferrin also helps to stimulate the immune system. It's believed to play a role in the prevention of cancer and disorders that are caused by the body's own immune system attacking itself.

Lactoferrin is one of the main proteins found in human breast milk. Lactoferrin may be one of the reasons a baby can absorb the iron in breast milk so well. Over 50% of the iron in breast milk is absorbed. That's much higher than the amount of iron a baby absorbs from infant formula which is approximately 12%.

Lactoferrin attaches to any of the extra iron that the baby doesn't absorb and keeps it from allowing harmful bacteria to grow in the baby's gastrointestinal tract.

When the growth of bad bacteria is kept to a minimum, it protects babies from illness and infection.

Levels in Mature Breast Milk

Colostrum is full of amazing substances that protect newborns from infection. Along with Secretory Immunoglobulin A (SIgA) and oligosaccharides, lactoferrin is seen in high amounts during the colostrum stage.

As the breast milk changes from colostrum to transitional breast milk to mature breast milk, the levels of lactoferrin go down, but lactoferrin continues to be present in the mature breast milk.

The Storage of Breast Milk

Whenever possible, fresh breast milk is best. Of course, that's not always realistic. So then, if breast milk has to be stored, how does lactoferrin handle the process?

Freezing Breast Milk: For the most part, breast milk can be frozen at 4 degrees C (-20 degrees C) for 3 months, and it will not lose much of its lactoferrin.

Thawing Breast Milk: Slowly thawing breast milk by placing it in the refrigerator or putting it into a container of warm water will help to prevent the destruction of the lactoferrin and other important immune properties. However, heating breast milk decreases the amounts of these protective substances, and boiling or sterilizing breast milk will kill most of the immune factors including lactoferrin.

Lactoferrin and Iron Supplements

Breastfeeding Mothers: Studies show that if a mother takes extra iron, it does not affect the lactoferrin in her breast milk.

Full-Term Breastfed Babies: Healthy, full-term babies who are breastfeeding exclusively absorb iron from breast milk very well. So, during the first 6 months of breastfeeding, the easily absorbed iron along with the baby's own iron stores should be enough to prevent iron deficiency. Plus, if a young breastfed infant gets too much iron, it is believed that it could be too much for the lactoferrin to handle and cause the unhealthy bacteria, especially E. coli and Candida albicans, in a child's intestines to overgrow. An overgrowth of harmful bacteria can cause diarrhea and abdominal issues.

But, by 6 months of age, solid foods that contain iron such as iron-fortified infant cereal should be added to the child's diet. And, some children may need iron added earlier, so the pediatrician may prescribe an iron supplement between 4 and 6 months of age. 

Premature Babies: Babies get most of the iron that they store in their body from their mother during the last 3 months of pregnancy. When a baby is born early, they doesn't have as much iron stored in their body as a full-term infant does. So, premature babies are more likely than full-term infants to develop iron deficiency anemia in the first 6 months of life. And, the smaller and earlier the baby is, the greater the risk. Therefore, exclusively breastfed preemies need iron supplements starting at about two weeks of age and continuing for up to 12-15 months.

Formula-Fed Babies: The iron in infant formula is not as easily absorbed as the iron in breast milk. So, to prevent problems related to an iron-deficiency, formula-fed babies should be receiving an iron-fortified infant formula.

If a child is receiving a low-iron formula, additional iron supplements are needed unless there is a specific medical reason that the child should not get extra iron.

Combination Feeders: Children who are both breastfed and formula-fed should be getting an iron-fortified infant formula as their supplement unless the child's doctor has advised otherwise for health reasons.

Lactoferrin and Infant Formula

Due to the health benefits of lactoferrin in breast milk, formula companies are working to add lactoferrin to infant formula. Since cow's milk also contains lactoferrin, although a much lower level compared to human breast milk, the lactoferrin in infant formula will most likely come from cows.

Of course, when you're comparing formula to breast milk it's difficult to determine how well the lactoferrin will work, especially when you have to balance out the iron levels, too. Even though infant formula is a safe, healthy alternative to breast milk, and scientists continue to improve upon it all the time, breast milk is still far superior since it already contains all the necessary ingredients for human infants in the correct balance.

Verywell Family uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  • American Academy of Pediatrics.  Policy Statement. Breastfeeding and the Use of Human Milk. Section on Breastfeeding. Pediatrics Vol. 129 No. 3 March 1, 2012.
  • Lawrence, Ruth A., MD, Lawrence, Robert M., MD. Breastfeeding A Guide For The Medical Profession Seventh Edition.  Mosby. 2011.
  • Newman, Jack, MD, Pitman, Theresa. The Ultimate Breastfeeding Book of Answers. Three Rivers Press. New York. 2006.
  • Rao, R., and Georgieff, M. K. Iron therapy for preterm infants. Clinics in Perinatology. 2009; 36(1): 27-42.
  • Riordan, J., and Wambach, K. Breastfeeding and Human Lactation Fourth Edition. Jones and Bartlett Learning. 2014.

By Donna Murray, RN, BSN
Donna Murray, RN, BSN has a Bachelor of Science in Nursing from Rutgers University and is a current member of Sigma Theta Tau, the Honor Society of Nursing.