What Is α-Lactalbumin?

Alpha-lactalbumin (α-lactalbumin) is a whey protein found in the milk of mammals, especially in breast milk. It makes up about 22% of total protein in human milk and 3.5% in cow’s milk [1]. In breast milk, α-lactalbumin is the dominant whey protein, followed by lactoferrin and immunoglobulins. In cow’s milk, β-lactoglobulin is the main whey protein, while α-lactalbumin ranks second. Notably, β-lactoglobulin is completely absent in breast milk—a key difference that will be explained further [1].

Why Is α-Lactalbumin Important for Children’s Immune Health?

1. Supports Innate Immune System Development

In the early months of life, when the adaptive immune system is still developing, infants rely on innate immunity alongside passive immunity from the mother. α-Lactalbumin and its derived peptides help strengthen this initial immune barrier, potentially neutralizing or inhibiting common pathogens, especially those affecting the gut. It also helps regulate immune responses, reduce inflammation, and enhance the ability to recognize harmful bacteria—preventing tissue damage and stimulating immune cell activity [1].

2. Helps Prevent Inflammatory Diseases

α-Lactalbumin indirectly promotes the production of glutathione, which combats free radicals and reduces inflammation. It also contains tryptophan, which supports immune and digestive health by producing serotonin, a neurotransmitter that regulates various bodily functions, including digestion [1]. Moreover, α-lactalbumin is a source of bioactive peptides with antibacterial properties, supporting both immune and digestive health during early development [1].

3. Enhances Adaptive Immunity and Gut Microbiota Balance

α-Lactalbumin contributes to the development of adaptive immunity by promoting a healthy gut microbiota—especially beneficial strains like Bifidobacteria and Lactobacillus [1]. The fermentation of these probiotics produces lactic acid, lowering colon pH and creating an unfavorable environment for harmful bacteria. This process improves mineral absorption and stimulates mucosal immunity. α-Lactalbumin also boosts the production of secretory IgA (sIgA) antibodies in the gut, helping neutralize pathogens at this key entry point.

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A study by Jean-Christophe Rozé and colleagues published in the British Journal of Nutrition compared infant formula enriched with α-lactalbumin (plus prebiotics and probiotics) to standard formula. Results showed that IgA levels in stool remained high in the enriched group from 1 to 6 months, while the control group experienced a significant decline [3].

In summary, α-lactalbumin plays a multidimensional role in optimizing immune development and overall health in young children. Its benefits not only protect against infections and immune disorders but also support physical growth through essential amino acids.

Who Should Prioritize α-Lactalbumin Supplementation?

1. Infants and Young Children

Breast milk is naturally rich in α-lactalbumin, offering numerous health benefits. For children who are not breastfed or are using infant formula, it’s important to choose formulas enriched with α-lactalbumin to closely match the nutritional profile of breast milk. Studies show that such formulas provide essential amino acids, improve digestive health, and offer benefits similar to breastfeeding [1].

2. Premature Infants

Premature babies (born before 37 weeks) often have underdeveloped digestive and immune systems. They require specialized nutrition that is easy to digest and absorb, while also boosting immunity. α-Lactalbumin is especially beneficial for these infants, helping strengthen the gut barrier, support beneficial microbiota, regulate immune responses, and promote optimal physical development [1].

3. Children with Cow’s Milk Protein Allergy

For children allergic to cow’s milk protein, nutritional choices must be made carefully. Breast milk is ideal because it does not contain β-lactoglobulin, a major allergen [4]. The primary whey protein in breast milk is α-lactalbumin, which may help reduce allergic reactions [5]. However, due to the complexity of allergic mechanisms, children with cow’s milk protein allergy should be managed by a qualified healthcare professional when switching to any dairy-based product.

4. Malnourished or Growth-Delayed Children

α-Lactalbumin is a rich source of essential amino acids, including tryptophan and lysine, which are vital for growth and development. It is considered a high-quality protein that meets recommended nutritional needs, helping children grow stronger and better resist illness during their early years [1].

When Should α-Lactalbumin Be Supplemented?

α-Lactalbumin should be a regular part of a child’s diet from birth to at least age 2. It is especially important during times when the immune system needs extra support—such as during illness, recovery, digestive disorders, or micronutrient deficiencies. Timely and adequate supplementation ensures the immune system is well-nourished and ready to defend against health challenges [6].

For formula-fed children, choose age-appropriate formulas that match their nutritional status and prioritize products containing whey protein rich in α-lactalbumin. This supports digestive health and provides the amino acids needed for rapid physical and brain development [5].

Reference

[1]. Layman DK, Lönnerdal B, Fernstrom JD. Applications for α-lactalbumin in human nutrition. Nutr Rev. 2018 Jun 1;76(6):444-460. Link

[2]. Lönnerdal B, Lien EL. Nutritional and physiologic significance of alpha-lactalbumin in infants. Nutr Rev. 2003 Sep;61(9):295-305. Link

[3]. Rozé, J. C., Barbarot, S., Butel, M. J., Kapel, N., Waligora-Dupriet, A. J., De Montgolfier, I., ... & Dupont, C. (2012). An α-lactalbumin-enriched and symbiotic-supplemented v. a standard infant formula: a multicentre, double-blind, randomised trial. British Journal of Nutrition, 107(11), 1616-1622. Link

[4]. Lemos L, Assis HC, Alves JL, Reis DS, Campos Canesso MC, Almeida Oliveira M, Moreira TG, Miranda Sato BK, Batista LA, Gomes Lenzi J, Moraes MA, Melo L, Resende B, Aguiar D, Rezende Souza B, Cara DC, Gomes-Santos AC, Faria AMC. Neuroimmune circuits involved in β-lactoglobulin-induced food allergy. Brain Behav Immun Health. 2022 May 21;23:100471. Link

[5]. Kim, S. Y., & Yi, D. Y. (2020). Components of human breast milk: from macronutrient to microbiome and microRNA. Clinical and experimental pediatrics, 63(8), 301. Link

[6]. Trabulsi J, Capeding R, Lebumfacil J, Ramanujam K, Feng P, McSweeney S, Harris B, DeRusso P. Effect of an α-lactalbumin-enriched infant formula with lower protein on growth. Eur J Clin Nutr. 2011 Feb;65(2):167-74. Link