What are the ingredients in colostrum?

November 24, 2025 •

3 min read

Often referred to as 'liquid gold,' colostrum is the first milky fluid produced by mammals after giving birth, packed with nutrients and antibodies. Understanding what are the ingredients in colostrum reveals why this initial fluid is so vital for a newborn's growth and immune system development.

Quick Summary

Colostrum is a concentrated, nutrient-dense fluid containing high levels of immunoglobulins, lactoferrin, growth factors, and essential macro- and micronutrients that support passive immunity and promote healthy development in newborns.

Key Points

Immune Defense: Colostrum is rich in protective immunoglobulins (antibodies) like IgA, IgG, and IgM, along with lactoferrin and cytokines that fight infections.
Promotes Growth: It contains high levels of growth factors such as IGF-1 and EGF, which stimulate cell growth and repair, especially in the gastrointestinal tract.
Nutrient-Dense: It is a concentrated source of essential vitamins (A, E, C), minerals (zinc, magnesium), and other nutrients vital for a newborn's development.
Supports Gut Health: With components like oligosaccharides and lactoferrin, colostrum helps establish a healthy gut microbiome and strengthens the intestinal wall.
Unique Composition: The composition of colostrum is distinct from mature milk, with higher concentrations of proteins and immune factors, but lower lactose in humans.
Sourcing for Supplements: Bovine colostrum is commonly used for human supplements due to its similar components and higher concentrations of certain factors compared to human colostrum.

A Complex Cocktail of Bioactive Components

Colostrum is a complex and species-specific biological fluid with a unique composition that differs significantly from mature milk. It contains a mixture of proteins, fats, carbohydrates, vitamins, minerals, and bioactive compounds vital for a newborn’s health and development. This initial fluid is crucial for passive immunity, especially in species like cows that don't transfer antibodies across the placenta, making colostrum their primary antibody source.

Immune Components: The Body's First Defense

Colostrum is known for its high concentration of immune-supporting factors essential for a newborn's underdeveloped immune system.

Immunoglobulins (Antibodies)

These proteins neutralize bacteria and viruses. Types and concentrations vary by species. Bovine colostrum is rich in IgG, while human colostrum has more IgA.

Immunoglobulin G (IgG): Abundant in bovine colostrum, providing systemic immunity.
Immunoglobulin A (IgA): Concentrated in human colostrum, providing local immunity by protecting mucous membranes.
Immunoglobulin M (IgM): Fights bacteria in the bloodstream.

Lactoferrin

Lactoferrin is a protein with antiviral, antibacterial, and anti-inflammatory properties. It inhibits bacterial growth by binding iron and supports healthy gut flora.

Other Antimicrobial and Immune Factors

Lactoperoxidase: Enzyme with antibacterial properties.
Lysozyme: Enzyme that breaks down bacterial cell walls.
Cytokines: Signaling peptides regulating immune functions and inflammation.
Proline-rich polypeptides (PRP): Small peptides that help regulate the immune system.
Leukocytes: White blood cells that fight infection.

Growth Factors: Stimulating Development and Repair

Colostrum contains hormones and growth factors that are vital for growth and maturation, particularly of the gastrointestinal tract.

Insulin-like Growth Factors (IGF-1 & IGF-2)

These stimulate growth and are important for muscle development and tissue repair.

Epidermal Growth Factor (EGF)

EGF stimulates cell growth and differentiation, important for repairing intestinal lining and other tissues.

Transforming Growth Factors (TGFα & TGFβ)

Involved in cellular processes like migration and regulation of epithelial cell growth.

Nutritional Profile: Macronutrients and Micronutrients

Colostrum's nutritional content fuels early development. It is higher in protein and lower in lactose and fat (in humans) compared to mature milk.

Key Macronutrients

Protein: Significantly higher than in mature milk.
Carbohydrates: Includes prebiotic oligosaccharides and lower lactose levels.
Fats: Provides essential fatty acids for energy and brain development.

Essential Vitamins and Minerals

Colostrum is rich in micronutrients supporting overall health, immunity, and vision.

Vitamins: High in fat-soluble vitamins (A, D, E, K) and important B vitamins and vitamin C.
Minerals: A source of zinc, magnesium, copper, calcium, and phosphorus essential for cellular function and bone development.

Comparison of Colostrum vs. Mature Milk

The table below highlights the differences in composition between colostrum and mature milk.


Component	Colostrum	Mature Milk
Immunoglobulins	High concentration, especially IgA in humans and IgG in bovines.	Significantly lower concentration.
Protein	Very high, up to twice as much in humans.	Lower, as the infant's needs change.
Growth Factors	Highly concentrated, crucial for neonatal development.	Much lower levels.
Lactose	Lower levels, easier for a new digestive system to process.	Higher levels, serving as the main source of energy.
Fat	Lower in humans, with a variable content in bovines.	Higher, providing more concentrated energy as the infant grows.
Vitamins (e.g., A, E)	Significantly higher levels.	Reduced concentration after the initial days.
Minerals (e.g., Zinc)	Higher concentration to support immunity.	Decreases to a steady level.

Conclusion

Colostrum is a complex and highly beneficial substance with a unique blend of immunoglobulins, growth factors, and concentrated nutrients that provide foundational immune protection and aid in early development. Its composition supports its reputation as a vital 'first food' for mammalian infants, and bovine-derived supplements are used by humans for similar benefits. Research continues to explore its applications in human health, highlighting the potency of the intricate ingredients in colostrum. For more information, refer to authoritative sources like the National Institutes of Health (NIH).

Frequently Asked Questions

The primary function is to provide essential immune protection and growth factors to the newborn, supporting the development of their immune system and gastrointestinal tract.

Immunoglobulins, or antibodies, bind to and neutralize pathogens like viruses and bacteria. In human colostrum, IgA coats the intestines to prevent infection, while in bovine colostrum, IgG provides systemic immunity.

Bovine colostrum contains many of the same beneficial components as human colostrum, making it a viable supplement for human consumption. It is pasteurized and processed into powders or pills.

The lower lactose and fat content in human colostrum makes it easier for a newborn's immature digestive system to process, focusing instead on delivering concentrated proteins and immune components.

Growth factors such as IGF and EGF stimulate cell proliferation and differentiation, which is crucial for the maturation of a newborn's gut lining and overall tissue development.

Colostrum contains oligosaccharides that act as prebiotics to feed beneficial gut bacteria and helps to coat the intestines, preventing harmful bacteria from being absorbed. This is essential for establishing a healthy gut microbiome.

Yes, the composition of colostrum changes dramatically over the first few days postpartum. The concentration of immunoglobulins, growth factors, and protein decreases rapidly as it transitions into mature milk.

Some people have concerns about whether sourcing bovine colostrum deprives calves of the fluid they need. However, many healthy dairy cows produce surplus colostrum.

The rich, golden-yellow color of colostrum, often referred to as 'liquid gold,' is due to the presence of carotenoids and high levels of Vitamin A.