Lactoferrin Simply Explained

1. What Is Lactoferrin?

Lactoferrin is a protein that binds iron. It belongs to the transferrin family. The body produces it itself. It is found in milk, especially in the first milk after birth. It is also contained in saliva, tears and in certain white blood cells. As a dietary supplement it is mostly obtained from cow's milk.

2. Where Is It Found, and What Is It Made From?

Lactoferrin is found in the milk of humans and other mammals. Most of it is in the first milk, which comes directly after birth. It is also found in saliva, tears and in the body's defense cells. For dietary supplements it is mostly obtained from cow's milk whey. There is also lactoferrin obtained from breast milk and genetically produced lactoferrin.

3. What Does Lactoferrin Do? What Research Shows

Immune Response and Defence Cells

Studies have investigated how lactoferrin affects the immune system. Messenger substances and defense cells in the blood were measured. The results were not consistent. With lactoferrin, the inflammatory messenger interleukin-6 was lower than with iron supplements 12. Compared with placebo (dummy), there were sometimes small differences, sometimes none 2333. Whether these changes in the blood prevent infections is still open.

Iron Status and Anaemia

In anemia due to iron deficiency, the red blood pigment rose more with lactoferrin than with oral iron preparations in several studies 21252830. The iron stores also filled better than with the comparison iron 2530. In pregnant women, the increase in one study was not greater than with iron sulfate 24. In children with kidney disease, oral lactoferrin acted similarly to iron as an infusion 31. Almost all studies compared lactoferrin with iron preparations, not with placebo (sham).

Gut Health and Gut Microbiota

In preterm infants, a marker for intestinal permeability was lower with lactoferrin 32. In healthy volunteers, lactoferrin dampened an increase in intestinal permeability triggered by painkillers 38. A review regards this as preliminary indications 6. In healthy employees in kindergartens, gastrointestinal complaints occurred less often in winter with lactoferrin than with sham 40. Many studies are small and the preparations differ.

Newborns and Preterm Infants

In preterm and low-birth-weight newborns, late-onset blood poisoning occurred less often with lactoferrin 13. In one study, fewer children died of blood poisoning (sepsis) 42. In preterm infants with feeding intolerance, full nutrition was reached faster 32. Meta-analyses also found less late-onset sepsis 57. In a severe intestinal inflammation of preterm infants, lactoferrin alone was not established as superior, but together with a probiotic it was 15. The amounts examined differ greatly.

Diarrhoea in Children

In weaned young children, diarrhea lasted somewhat shorter with lactoferrin, and severe courses with dehydration were less common than with placebo 43. However, how often the children got diarrhea did not change 43. Young children with enriched milk formula had acute gastrointestinal complaints less often 39. A meta-analysis found less diarrhea in children 7. Another study found no difference in the frequency of diarrhea 45. Overall, about as many studies found a benefit as found no difference.

Respiratory Tract Infections

Preschool children with recurrent infections had fewer episodes and shorter complaints with lactoferrin 34. In healthy adults, respiratory and general complaints were lower than with placebo 22. A meta-analysis (combined analysis of many studies) found a lower risk of respiratory infections 4. Another found no established difference in children 7.

Oral and Dental Health

For mouth and throat discomfort caused by dry air, a single intake relieved the discomfort 36. For bad breath, tablets that combined lactoferrin with other enzymes lowered sulfur compounds in the breath 3537. In healthy adults, tablets with lactoferrin and lactoperoxidase lowered the gingival index, a measure of gum inflammation, at the higher dose 41. In chronic periodontitis, such tablets did not change gum findings more than sham tablets 27. Most studies tested only combinations with other substances, so the evidence is only moderate.

Other Investigations

In this area, many controlled studies (with a comparison group) and several meta-analyses were reviewed. The results are mixed. In pregnant women with recurrent urinary tract infections, fewer urinary tract infections occurred with lactoferrin in one study than in the comparison group 19. In severe blood poisoning, mortality with a genetically engineered lactoferrin was higher in one study 17 and lower after six months in another than with placebo 44. In overweight children with fatty liver, weight and body mass index decreased more with lactoferrin and diet than with diet alone 26. Many studies are small and the forms tested are inconsistent.

4. How Was Lactoferrin Taken in the Studies?

Lactoferrin is usually taken as powder or liquid. In studies, it was predominantly tested as bovine lactoferrin. Less often, it was human or genetically engineered lactoferrin. Some of the studies used formula milk, yogurt, mouth rinses, gels, or ointments. Often it was not stated whether the iron-free or iron-saturated form was used. In some studies, lactoferrin was tested only together with other substances, such as probiotics, lysozyme, iron, or folic acid.

5. Is Lactoferrin Safe? Side Effects in the Studies

Most studies report good tolerability of lactoferrin. Adverse events were similar to those with placebo. In iron deficiency, lactoferrin was described as better tolerated than high-dose iron. Abdominal pain and digestive complaints occurred less often. Individual reports mention constipation, vomiting, loss of appetite or diarrhea. In two studies with seriously ill adults, mortality with genetically produced lactoferrin was once increased and once improved. Another study saw no difference.

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