Components of Colostrum

Colostrum comprises macronutrients, micronutrients, growth factors, immunoglobulins, lactoferrin, etc. All of these components are discussed below.

1.  Protein

Bovine colostrum (BC) is described as a nutrient-rich fluid that bovine animals produce in the first weeks after giving birth and it is generally higher in protein (i.e. ~15% protein vs. 3.5% in bovine milk), especially ‘whey proteins viz., β-lactoglobulin (β-LG) and α-lactalbumin (α-LA)’. The initial concentration of β-LG in BC ranges between 7.9 and 30 mg/mL afterward, dropping to 8 mg/mL following subsequent milking. BC also contains 2.63 mg/mL bovine serum albumin, but its amount decreases markedly within 24 hours, attaining normal levels following the second week of calving. In addition to these major proteins, BC contains several minor proteins, such as ‘fibrinogen β-chain, chitinase 3-like 1, α-antitrypsin, complement C3 α-chain, gelsolin and apolipoprotein H’ (McGrath et al., 2016; Sangild et al., 2021).

2.  Fat

The fat content of BC is reported to be approximately 7% and abundant in some fatty acids such as myristic, palmitic, palmitoleic acids and conjugated linoleic acid (CLA) compared to that of bovine milk. The functions of CLA include marked reduction in ‘cancer risk, atherosclerosis, inflammation, obesity and diabetes’ in both humans and animals (Linehan et al., 2023).

3.  Carbohydrate

Comparatively, BC and human colostrum contain a greater amount of lactose (1.2% and 2-2.9% respectively) in contrast to bovine milk. 3'-Sialyllactose is the most prominent bovine colostrum oligosaccharide (BCO), representing 70% of the total oligosaccharide content found in BC. The major functions of BCO include competitive inhibition of pathogenic bacteria such as ‘Escherichia coli, Cronobacter sakazakii and Helicobacter pylori’ by mimicking the surface carbohydrates of gut epithelial cells and occupying adhesion sites. Low amounts of lactose result in the production of highly viscous milk with reduced water content, as lactose acts as an osmo-regulator (McGrath et al., 2016; Sangild et al., 2021).

4.  Vitamins and Minerals

“BC comprises fat-soluble (A, D, E, and K) as well as water-soluble (B1, B2, B3, B5, B6, B7, B9, B12 and C) vitamins. Fat-soluble vitamins and some minerals (i.e. calcium, sodium, copper, selenium, iron, zinc, magnesium, manganese and phosphorus) are found in higher amounts in BC than in mature milk” (Puppel et al., 2019).

5.  Antimicrobial factors

Numerous bioactive components discovered in BC include immunoglobulins, lactoferrin, lysozyme and α-lactalbumin. In addition, certain minor components such as cytokines, growth factors and hormones are also found.

Immunoglobulin: BC assists in the protection of calves from infection thanks to the presence of immunoglobulins (i.e. IgG, IgA and IgM) in abundant amounts. IgG is the most prominent immunoglobulin, representing 85–90% of the total immunoglobulin. Ig aids in restricting pathogens from binding to host cells, presenting pathogens to macrophages for destruction, enhancing ‘T- and B-cell’ immune activation, maintaining a balanced intestinal microflora and inducing IgA production. IgG is responsible for transmitting immunity against specific pathogens. For example, BC proves to be effective in preventing and curing various types of infections, such as diarrhea and respiratory infections, as well as improving the immune system and overall health in humans. Human colostrum was effective in preventing ‘rotavirus’ infection, treating ‘upper respiratory tract infections’ and reducing the severity of diarrhea in children suffering acute gastroenteritis (McGrath et al., 2016; Sangild et al., 2021; El-Loly, 2022).

Lactoferrin: Lactoferrin (LF) is a red glycoprotein that binds to iron and its concentration ranges from 0.34 to 1.96 g/L. The health advantages associated with LF consist of protection against bacteria, fungi and viruses as well as reduction of cancer risk and inflammation, regulation of the immune system and promotion of cell growth. LF squeezes out iron from the medium and prevents microbes from utilizing it, as it is necessary for the growth of microbes (El-Loly, 2022).

Lysozyme: Lysozyme is a powerful antimicrobial agent found in BC, is effective against several types of bacteria except lactic and propionic acid bacteria and has a vital role in protecting calves against infection in the early stages of their lives (Puppel et al., 2019).

Lactoperoxidase: The concentrations of lactoperoxidase in BC range from 13 to 30 mg/L. It uses hydrogen peroxide to convert thiocyanate ions into reactive products that kill bacteria such as ‘Pseudomonas aeruginosa, Salmonella typhimurium, Listeria monocytogenes and Staphylococcus aureus’. As an antioxidant enzyme, it also protects cells against free radical damage (Linehan et al., 2023).

Proteinases: BC contains 10-fold higher concentrations of plasmin (a serine protease) in contrast to mature milk. The activity of plasmin decreases in BC following the fifth day of milking. In BC, cathepsin D and protease enzyme activity is lower than in mature milk (Poonia and Shiva, 2022)

Cytokines: Cytokines such as ‘interleukins (ILs), tumor necrosis factors (TNFs), and interferons (IFNs)’ have profound biological effects at small concentrations (i.e. 10 to 1000 pg/mL). “Specific examples of cytokines found in BC include IL-1, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12, IL-13, IL-16, IL-18, IFN-γ, TNF-α, and TNF-γ receptors” (McGrath et al., 2016; Linehan et al., 2023).

Leukocytes: BC contains approximately 106 leucocytes (i.e. lymphocytes, macrophages, epithelial cells and polymorphonuclear cells) per mL and helps to maintain the immune system (Poonia and Shiva, 2022).

Hormones: A number of hormones detected in BC consist of “growth hormone, prolactin, somatostatin, oxytocin, luteinizing hormone-releasing hormone, leptin, thyroid-stimulating hormone, thyroxine, calcitonin, estrogen, and progesterone”. The role of such hormones is to improve the growth of the calf by entering the bloodstream through the intestinal barrier, as they are particularly permeable in calves (Linehan et al., 2023).

MAJOR HEALTH BENEFITS OF COLOSTRUM

Colostrum helps improve the immune system, control immunological responses, maintain intestinal flora and promote tissue growth. BC is an excellent nutritional supplement for geriatrics (older aged individuals) to fight against the immune-suppressing consequences of stress, illness etc. (Linehan et al., 2023).

Immunological Support

Physically active adolescents can increase their secretory IgA levels through the consumption of colostrum supplements. In children with IgA deficiency, BC successfully lowered the severity of ‘upper respiratory tract infections. BC’s immune-stimulating qualities have also been demonstrated to prevent tongue, esophageal, bladder, lung and colon cancers. In studies, lactoferrin has been found to inhibit various viruses, emphasizing its role in immune modulation. The bioactive substances found in BC are highly beneficial to human health, especially in terms of improving the immune system, maintaining a balance of the intestinal flora and promoting tissue regeneration. However, it appears that supplementing with BC only has a minor effect on raising serum levels of immunoglobulin when given to trained and physically active individuals. Whey contains α-lactalbumin, a type of protein that can help increase immune responses and promote glutathione synthesis. Leukocytes in BC are used as a defensive mechanism against pathogens that invade the mammary gland (Wasowska and Puppel, 2018).

Antimicrobial properties

“Lactoferrin (LF) demonstrates favourable effects on certain types of neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease and Friedreich’s ataxia”. Its impact extends to inducing apoptosis, acting as an antioxidant, influencing microbial proliferation and adhesion, and serving as an immune mediator by modulating oxidative stress and systemic inflammatory responses. LF also plays a role in cytokine production, finds application in infant formulas, and contributes to intestinal health while addressing issues such as arthritis and allergic inflammation. In the context of infant nutrition, it is notable that when an infant consumes 500 mg of polymeric IgA (p IgA), approximately 150 mg remains undegraded in the small intestine. This quantity of antimicrobial protein assumes a notably significant role in bolstering mucosal host defense in infants. The primary function of p IgA lies in preventing microbial pathogens from adhering to the intestinal epithelial surface. LF along with secretory IgA (S IgA) and lysozyme play vital roles in the antibacterial defense mechanisms of the intestinal mucosa and are naturally present in colostrum (Mehra et al., 2021).

Anti-inflammatory Effects

Cytokines and interleukins modulate the immune system by enhancing ‘T-cell activity’, exerting antiviral effects, contributing to inflammatory responses, demonstrating efficacy in chemotherapy and playing a pivotal function in cellular communication. “Mainly, interleukins 1 to 6 (IL–1-6), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (INF-γ) regulate TNF-induced inflammation and involve autocrine or paracrine functions, cell proliferation, immune response mediation during infections, stress and bronchial asthma.”. TNF-α and IL-4 and 5 are associated with eosinophil activation, while IL-10, 13 and IL-17 (proinflammatory Th1 cytokines secreted by T helper cells) exhibit anti-inflammatory properties (in arthritic joints) and are involved in signaling pathways and IgE-mediated allergic responses. The presence of vitamin E in colostrum was observed to mitigate inflammation (Mehra et al., 2021).

Wound Healing Properties

In addition to its significant immune-boosting properties, BC exhibits remarkable capacity for promoting the repair and growth of the musculoskeletal system. BC contains two crucial growth factors: “transforming growth factors alpha and beta (TGF-α and TGF-β) and insulin-like growth factors 1 and 2 (IGF-1 and IGF-2)” and is involved in muscle and cartilage repair due to its unique biochemical properties. TGF-α and TGF-β are essential for normal cellular activities, including embryonic development and cell proliferation. Its role in wound healing has marked implications for recovery after trauma and surgery. IGF-1 (wound-healing and anabolic hormone) effectively mitigates catabolism and is the sole growth factor capable of independently stimulating muscle growth and repair (Uruakpa et al., 2002)

Athletic Performance and Muscle Recovery

BC has gained significant prominence as a valuable dietary supplement due to various health benefits for overall body development and muscle building, particularly for athletes and fitness trainers engaged in strenuous training regimens. Leptin and IGF-1 play a pivotal role in metabolic processes and contribute to increasing lean body mass while simultaneously reducing body fat, hence diminishing the propensity for weight gain. Intense physical exercise often leads to chronic fatigue syndrome in athletes and fitness trainers, primarily due to a reduction in T-lymphocytes and NK cells, which compromises the immune system. Another challenge associated with aging is the loss of muscle mass and the increased difficulty of shedding excess fat. BC IGF-1 proves instrumental in fostering the growth of lean muscle tissue and the utilization of fat for energy (Uruakpa et al., 2002).

BC is rich in epidermal growth factors (EGFs) that serve diverse functions such as “wound healing, addressing inflammatory diseases, repairing damaged gastrointestinal tissues and rejuvenating damaged gastric and intestinal tissues, as well as in the differentiation and proliferation of epidermal cells. BC may act as a preventive measure against cardiovascular diseases, autoimmune disorders and allergies due to the presence of PRP. IGF-1 contributes to raising high-density lipoprotein cholesterol levels and lowering low-density lipoprotein cholesterol levels, potentially reducing the risk of arterial atherosclerosis formation. BC also shows promise as a novel therapy for the treatment of drug-induced gastrointestinal damage (Uruakpa et al., 2002).

Amino Acids and Functionality of the Thymus Gland

Insufficient dietary intake of tryptophan can lead to a reduction in serotonin levels within the central nervous system, thereby engendering pronounced behaviour alterations (such as ‘hyperactivity, depression, anorexia nervosa, anxiety disorder and impulsive conduct’) in padiatric individuals. The presence of ‘proline-rich polypeptide (PRP)’ in BC plays a pivotal role in the regulation of thymic gland functionality. The PRP component also exhibits a notable capacity for mitigating the manifestation of pain, inflammation, and swelling, which typically arise from an unwarranted overproduction of lymphocytes and T cells. Such overproduction is frequently associated with allergic reactions and autoimmune disorders, making PRP a promising therapeutic agent for such immunological problems (Playford and Weiser, 2020; Sangild et al., 2021).

Colostrum Powder

“Colostrum powder is a colostrum-based product obtained by the drying of colostrum by suitable methods while retaining the essential characteristics of colostrum.”

Colostrum Powder Production

Spray Drying

Spray drying for powder preparation has been limited due to heat-induced damage to colostrum proteins since the product remains above the air outgoing wet bulb temperature. Colostrum powder was made by spray drying under specific conditions, such as (i) feed temperature – 32°C, (ii) atomizer pressure – 0.7 MPa and (iii) inlet and outlet air temperatures – 125°C and 49°C respectively. Investigations indicate that spray drying reduces IgG levels in colostrum by approximately 50% compared to untreated colostrum. Importantly, the cost of spray-drying colostrum was approximately 2.5 times lower than that of freeze-drying and microwave vacuum evaporation methods (Borad and Singh, 2018).

Freeze Drying

Freeze-drying is a favourable technique for drying heat-sensitive biological materials owing to its minimal processing temperatures and remains one of the most successful process for obtaining high-quality colostrum powder. This process rapidly transforms frozen material from a hydrated to a dehydrated state, effectively minimizing nutrient loss; hence, the biological activity of Ig is reduced by only 10%. Freeze-dried colostrum is known for its stability, ease of handling and suitability for passive immunization. Some limitations restrict the industrial application of freeze-dried colostrum powder with stable bioactive components, such as high production costs, lengthy processing times and difficulties in scaling up the freeze-drying process. For the preservation of heat-sensitive PRP and IgG proteins in BC, low-heat pasteurization and low-heat indirect drying have been explored as alternatives.

VARIOUS APPLICATION OF BOVINE COLOSTRUM

Specialized dairy products enriched with colostrum-derived immunoglobulins (Ig) offer a promising avenue to improve immune function in individuals with compromised immune systems, including infants, children and elderly individuals. Notably, IgG from various mammals plays a pivotal role in providing passive immunity, making it a significant component of BC that contributes to immunological activity against infectious diseases (Bagwe et al., 2015)

The inclusion of bovine or buffalo colostrum in the manufacture of various dairy and food products (such as milk-based drinks, butter, ice cream, white soft cheese, fermented milk, yoghurt, kefir, beverages, infant formulas and nutritional chewing gums) has been explored by several researchers. The use of colostrum encapsulated in milk desserts has also been developed through the use of a double emulsion technique to safeguard sensitive ingredients, particularly Ig, especially for athletes and sport persons (Playford and Weiser, 2020; El-Loly, 2022).

For the production of the fermented product, four different ratios of colostrum to milk were employed viz., colostrum: milk at ratios of 100:0, 80:20, 60:40, and 50:50. The sensory evaluation of the fermented colostrum product indicated that as the proportion of whole milk increased, transitioning from the control with a 100:0 ratio of colostrum and milk, the scores related to sensory attributes such as appearance, flavour, texture, consistency and overall acceptability exhibited a declining trend.  Stirred yoghurt was incorporated with BC in various proportions (10, 20 and 30%) which resulted in an increase in the gel setting time and protein content of the yoghurt as its amount increased. The chemical composition of the milk showed higher levels of fat, ash, total solids, and mineral contents. Furthermore, an increasing trend was observed for viscosity, water-holding capacity and antioxidant activity with increasing amounts of added colostrum  (El-Loly, 2022).

The gelling property of colostrum has a longstanding tradition in northern India, particularly in the state of Haryana. Conventionally, Khees is prepared using colostrum obtained from the first to fifth day of milking. Two types of sweeteners viz., jaggery and cane sugar (constituting 13 to 14% of the ingredients), were successfully employed for khees preparation with desirable organoleptic quality (Poonia and Shiva, 2022).

‘Biotest Pharm GmbH’, based in Frankfurt, Germany, manufactures a product known as ‘Lactimmunoglobulin Biotest’, designed for human use. This product includes immunoglobulins sourced from the colostrum of non-immunized cows. In the commercial domain, colostrum-based products, often categorized as nutraceuticals, are produced in various formats such as tablets, capsules, and powders by multiple companies. ‘Biostrum Nutritech Pvt. Ltd.’ employ buffalo colostrum, ‘APS BioGroup’ utilizes cow colostrum, while ‘Capra Wholefood Nutritionals’ use goat colostrum in their respective formulations (Centi et al., 2022).

CONCLUSION

Colostrum offers many health benefits, particularly for those who want to improve their immune system, increase muscle growth, decrease inflammation and enhance athletic performance. Colostrum powder is prepared using a spray- or freeze-drying process, can be stored for long periods of time and does not require refrigeration. Colostrum can be successfully incorporated in the production of various food products, such as milk-based drinks, butter, ice cream, fermented milk, yoghurt, kefir, beverages, infant formulas and nutritional chewing gums. The application of colostrum or its products as therapeutic agents requires further clinical trials on humans and animals to estimate the optimum dosage and ensure long-term safety.

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