Beyond immunoglobulins, bovine colostrum contains lactoferrin, growth factors such as IGF-1 and TGF-β1, lysozyme, proline-rich polypeptides and oligosaccharides. Many are far more concentrated than in regular milk: lactoferrin at 1.5–5 mg/mL versus 0.02–0.75 mg/mL, and IGF-1 at up to 2,000 µg/L versus under 10 µg/L (McGrath et al., 2015).
Key takeaways
- Colostrum can contain up to 250 times more lactoferrin than mature milk (Davison, 2021).
- Growth factors IGF-1 and TGF-β1 are many times higher in colostrum than in milk.
- Taking 40 g of colostrum a day for months did not raise blood IGF-1 levels in research (Playford and Weiser, 2021).
- Not everything is concentrated: lactoperoxidase levels are similar to regular milk (McGrath et al., 2015).
What is lactoferrin?
Lactoferrin is an iron-binding protein found in milk and other body fluids. Because it holds on to iron tightly, it has attracted a lot of research interest, and it's one of the best-known bioactives in colostrum after the immunoglobulins.
First-milking bovine colostrum contains 1.5–5 mg/mL of lactoferrin, compared with 0.02–0.75 mg/mL in regular milk (McGrath et al., 2015). A 2021 review put the difference at up to 250 times more lactoferrin in colostrum than mature milk (Davison, 2021).
New to all this? Our Colostrum 101 guide gives a quick overview, and immunoglobulins explained simply covers colostrum's headline act.
What growth factors are in colostrum?
Growth factors are signalling proteins that help cells grow and renew. For a newborn calf, they're thought to be part of what helps the young gut develop. The two most studied in colostrum are:
- IGF-1 (insulin-like growth factor 1): 50–2,000 µg/L in colostrum, compared with less than 10 µg/L in milk (McGrath et al., 2015).
- TGF-β1 (transforming growth factor beta 1): 12–43 µg/L in colostrum, compared with 0.8–3.5 µg/L in milk (McGrath et al., 2015).
Growth factors are among the components researchers discuss when explaining colostrum's effects on the gut lining. You can read about those studies in colostrum and gut health.
Does the IGF-1 in colostrum raise your IGF-1?
This is a common question. In research summarised by Playford and Weiser (2021), taking 40 g of colostrum a day for months did not raise blood IGF-1 levels. That's 20 times a standard 2 g teaspoon serve.
However, because IGF-1 is on the World Anti-Doping Agency's Prohibited List, WADA advises athletes against taking colostrum (Davison, 2021). If you compete in drug-tested sport, read colostrum for athletes before you start.
Lysozyme and proline-rich polypeptides
Lysozyme is a naturally occurring enzyme found in colostrum (Playford and Weiser, 2021). Lysozyme is also found in human tears and saliva. It's part of the broad mix of protective proteins that make colostrum different from regular milk.
Proline-rich polypeptides (PRPs) are a group of small peptides rich in the amino acid proline. In colostrum, PRPs are a mixture of at least 32 peptides, each between 0.5 and 3 kDa in size (Playford and Weiser, 2021). They are much smaller than immunoglobulins and are an area of ongoing research.
What are colostrum oligosaccharides?
Oligosaccharides are short chains of sugar molecules. They aren't digested like regular sugars, and in milk they're studied for their role in the gut. In bovine colostrum, oligosaccharides are mostly sialylated (they carry a sialic acid group), and one called 3′-sialyllactose makes up about 70% of them (McGrath et al., 2015).
Human milk is well known for its oligosaccharides too. Research on bovine colostrum oligosaccharides is still developing, so we won't overstate it.
Is everything more concentrated in colostrum?
No, and it's worth being honest about that. Many bioactives are dramatically higher in colostrum, but not all of them. Lactoperoxidase, an enzyme sometimes mentioned in colostrum marketing, is not concentrated: it's found at 13–30 mg/L in colostrum and 11–45 mg/L in regular milk (McGrath et al., 2015).
| Bioactive | Colostrum | Mature milk | Source |
|---|---|---|---|
| Immunoglobulins | 70–80% of protein | About 1% of protein | Playford and Weiser, 2021 |
| Lactoferrin | 1.5–5 mg/mL | 0.02–0.75 mg/mL | McGrath et al., 2015 |
| IGF-1 | 50–2,000 µg/L | Under 10 µg/L | McGrath et al., 2015 |
| TGF-β1 | 12–43 µg/L | 0.8–3.5 µg/L | McGrath et al., 2015 |
| Lactoperoxidase | 13–30 mg/L | 11–45 mg/L | McGrath et al., 2015 |
Levels also vary between cows and between milkings, and commercial products can vary up to six-fold in bioactivity (Playford and Weiser, 2021). That's one reason we suggest comparing products carefully; our colostrum buying guide walks you through it.
Whole colostrum or isolated ingredients?
You can buy some of these components, such as lactoferrin, as stand-alone supplements. Whole colostrum is different: it delivers the full natural mix of immunoglobulins, lactoferrin, growth factors, peptides and oligosaccharides together, in the proportions the cow produced.
MUUU Colostrum Powder is 100% pure bovine colostrum from New Zealand, with no other ingredients. One level teaspoon (2 g) provides 2,000 mg. Keep in mind that research doses were often 10–20 g a day (Davison, 2021), more than one standard serve, and follow the label directions.
FAQs
Is lactoferrin in colostrum the same as in lactoferrin supplements?
Lactoferrin supplements are usually made from cow's milk or whey, so it's the same type of protein. The difference is that colostrum provides lactoferrin alongside many other bioactives, rather than on its own.
Does heat damage colostrum bioactives?
Heat can change the shape of proteins. For IgG, effects start above about 65°C (Bogahawaththa et al., 2017). To be safe with all the proteins, mix colostrum into cool or warm foods and drinks rather than hot ones.
Which bioactive is most abundant in colostrum?
Immunoglobulins, by a long way. They make up 70–80% of colostrum's protein, and IgG is the main type (Playford and Weiser, 2021).
References
- McGrath BA, Fox PF, McSweeney PLH, Kelly AL. Composition and properties of bovine colostrum: a review. Dairy Sci Technol. 2016;96:133–158 (published online 2015). https://link.springer.com/article/10.1007/s13594-015-0258-x
- Playford RJ, Weiser MJ. Bovine colostrum: its constituents and uses. Nutrients. 2021;13(1):265. https://www.mdpi.com/2072-6643/13/1/265
- Davison G. The use of bovine colostrum in sport and exercise. Nutrients. 2021;13(6):1789. https://www.mdpi.com/2072-6643/13/6/1789
- Bogahawaththa D, et al. Food Hydrocolloids. 2017;72:350–357. https://doi.org/10.1016/j.foodhyd.2017.06.017
This article is general information, not medical advice. Always read the label and follow the directions for use.
