Lactoferrin — Iron-Binding Immune Glycoprotein — Immunity
Multifunctional glycoprotein from milk with antimicrobial, immune-modulating, and iron-regulating properties. Dietary supplement.
Overview
Lactoferrin is an 80 kDa iron-binding glycoprotein belonging to the transferrin family, found in high concentrations in human colostrum (7 g/L), breast milk (1-2 g/L), tears, saliva, nasal secretions, and neutrophil granules. It is one of the most important components of the innate immune system, with broad antimicrobial (antibacterial, antifungal, antiviral, antiparasitic), anti-inflammatory, immunomodulatory, and iron-regulatory properties. Lactoferrin's antimicrobial action occurs through multiple mechanisms: iron sequestration deprives pathogens of essential iron, direct binding to bacterial lipopolysaccharide (LPS) neutralizes endotoxin, and lactoferricin (a peptide fragment released by pepsin digestion) has direct bactericidal activity by disrupting microbial membranes. In the gut, lactoferrin promotes the growth of beneficial bacteria (Lactobacillus, Bifidobacterium) while inhibiting pathogenic organisms, functioning as a prebiotic-like immune modulator. Clinical evidence supports lactoferrin supplementation for iron deficiency anemia in pregnancy (non-inferior to ferrous sulfate with fewer GI side effects), reducing the incidence of necrotizing enterocolitis in premature infants, and modulating immune responses in various infectious conditions. Bovine lactoferrin, which shares 69% sequence homology with human lactoferrin, is the most commonly available supplement form and retains most biological activities.
Indications
- Dietary supplement: Immune support and gut health
- Evidence-supported: Iron deficiency anemia in pregnancy (alternative to oral iron)
- Evidence-supported: Necrotizing enterocolitis prevention in preterm infants
- Emerging evidence: Upper respiratory tract infection prevention
- Emerging evidence: Gut microbiome modulation and GI health
Mechanism of Action
Lactoferrin binds iron with high affinity (Kd ~10^-20), depriving pathogenic bacteria of this essential nutrient for growth and biofilm formation
Dosing
| Compound | Dose | Frequency | Notes |
|---|---|---|---|
| Bovine Lactoferrin | 200-250 mg | Once or twice daily | Standard immune support dose |
| Bovine Lactoferrin | 100 mg | Twice daily | Iron deficiency in pregnancy (with iron supplementation) |
| Bovine Lactoferrin | 200-600 mg | Once daily | Gut health and microbiome support |
Evidence Grade
GRADE B
Safety & Contraindications
- Generally recognized as safe (GRAS) — excellent safety profile
- Rare: GI upset (diarrhea, bloating) at high doses
- Rare: allergic reaction in individuals with cow's milk protein allergy (bovine lactoferrin)
- May affect iron absorption — beneficial in iron overload, caution in iron deficiency if not supplementing iron
- Avoid bovine lactoferrin in cow's milk allergy