Research on goat milk

A comprehensive study comparing the composition of whole goat and cow milk was completed in Spain (Ceballos et al, 2009).  This study confirmed that compared to cow milk, goat milk has:

  • a lower amount of aS1-casein,
  • the same total quantity of essential amino acids,
  • a higher content of medium-chain fatty acids (C6–14),
  • more conjugated linoleic acid,
  • greater quantities of Ca, P, Mg and Cu.

In another study by the same researchers, animals fed goat milk were found to make better use of the nutrients in the milk than the nutrients from cow milk (Ceballos et al, 2009).  In particular, the utilization of nitrogen from goat milk proteins was greater than from cow milk proteins.  Thus, goat milk and cow milk were found to be different, both in terms of composition and nutritional quality. 

Ceballos LS, Morales ER, Adarve GT, Castro JD, Martinez LP, Sampelayo MRS(2009) Composition of goat and cow milk produced under similar conditions and analyzed by identical methodology. Journal of Food Composition and Analysis  22: 322–329.

Ceballos LS, Morales ER, Martínez LP, Extremera FG, Sampelayo MR. (2009) Utilization of nitrogen and energy from diets containing protein and fat derived from either goat milk or cow milk. Journal of Dairy Research 76: 497-504.

Milk not only contains major nutrients such as protein, but also has a range of other ingredients important for promoting infant health.  A group of these ingredients make up what is called the non-protein nitrogen fraction of milk.  This fraction consist of urea, free amino acids, nucleotides and nucleosides, polyamines, creatinine and other compounds containing nitrogen.  Although present at very low concentrations, the components of the non-protein nitrogen fraction have very important developmental functions in infants and for the older, growing child.

Research completed by AgResearch in New Zealand shows that goat milk is rich in nucleotides, taurine and polyamines.  Goat milk infant formula also contains similar levels of nucleotides to human milk, meaning that fortification with nucleotides is not necessary for goat milk formula.  In contrast, cow milk formula manufacturers need to add synthetic nucleotides to produce formulas with nucleotide levels comparable to human milk.  Similarly, goat milk naturally contains much higher levels of polyamines than cow milk.

A copy of the publication can be downloaded from

Goat milk is widely reported to be digested more easily than cow milk, but there is limited scientific evidence of this.  Researchers based at the Norwegian University of Life Sciences and University of Oslo in Norway set out to correct this.  These researchers used human digestive enzymes to measure the breakdown of cow and goat milk proteins.  Cow milk proteins were digested nearly a third slower than goat milk proteins.  In addition, they found that three times more beta-lactoglobulin from goat milk was digested compared to the same protein from cow milk.  Beta-lactoglobulin is one of the main causes of allergies to milk and is most resistant to digestion.  The greater digestion of beta-lactoglobulin from goat milk helps to minimise the allergenic burden of goat milk.

A copy of the publication can be downloaded from

It is the structure of goat and cow caseins that may partly explain why goat and cow milk are digested differently.  Caseins, the main proteins in goat and cow milk, form a suspension of particles called micelles.  The action of digestive acids and proteases in the stomach cause these casein micelles to coagulate and form:

  •  a gel called “curd” (white layer) containing mainly casein proteins, fats and some minerals; and
  •  a whey (clear liquid) containing mostly water, lactose and whey soluble proteins, released from the curd.

This process is the same as cheese making.  It is well known that when casein from goat milk coagulate to form cheese it is softer and more fragile than cheese made from cow milk.  Researchers at Fort Valley State University USA determined that the casein micelles of goat milk were one and half times larger than casein micelles from cow milk (Park 2007).  This would be enough to explain the loose, more fragile casein curd structure of goat milk.  When in the baby’s stomach, this soft curd would be digested more rapidly. 

Park, Y. (2007). Rheological characteristics of goat and sheep milk. Small Rumin Res, 68, 73-78.

A series of studies in animals with symptoms of malabsorption show more efficient absorption of calcium, phosphorus, iron, copper, zinc, magnesium and selenium from goat milk compared to cow milk (Barrionuevo et al, 2002; Alferez et al, 2003; Campos et al, 2003; Lopez-Aliaga et al, 2003).  These studies suggest goat milk can benefit micronutrient absorption in situations where the absorption capacity of the intestine is compromised.

Other studies also suggest goat milk may benefit situations of iron deficiency.  Anaemic rats fed goat milk had higher liver weights and efficiency of haemoglobin regeneration than those given cow milk, consistent with the greater bioavailability of iron from goat milk (Park et al, 1986).  Other studies show that goat milk enhances bioavailability of both iron (Nestares et al 2008) and magnesium (Nestares et al, 2008) and improves bone health (Diaz-Castro et al, 2011) in situations of iron anaemia.  

Lopez-Aliaga I, Alferez MJM, Barrionuevo M, Lisobnona F, Campos MS (2000) Influence of goat and cow milk on the digestive and metabolic utilization of calcium and iron. J Physiol Biochem 56:201-208.
Park YW, Mahoney AW, Hendricks DG (1986) Bioavailability of iron in goat milk compared with cow milk fed to anemic rats. J Dairy Sci 69:2608-2615.
Alferez MK, Lopez-Aliaga I, Nestares T, Diaz-Castro J, Barrionuevo M, Ros PB, Campos MS (2006) Dietary goat milk improves iron bioavailability in rats with induced ferropenic anaemia in comparison with cow milk.  Int Dairy J 16: 813-821.
Barrionuevo M, Alferez MJ, Lopez AI, Sanz SM, Campos MS (2002) Beneficial effect of goat milk on nutritive utilization of iron and copper in malabsorption syndrome. J Dairy Sci 85:657-664.
Alferez MJM, Lopez-Aliaga I, Barrionuevo M, Campos MS. (2003) Effect of dietary inclusion of goat milk on the bioavailability of zinc and selenium in rats.  J Dairy Res 70: 181-187.
Campos, M. S., Lopez Aliaga I, Alferez MJM, Nestares T, Barrionuevo M (2003) Effects of goats’ or cows’ milk on nutritive utilization of calcium and phosphorus in rats with intestinal resection.  Brit J Nutr 90: 61-67.
Lopez-Aliaga I, Alferez MJM, Barrionuevo M, Nestares T, Sanz Samplayo MR, Campos MS (2003) Study of the nutritive utilization of protein and magnesium in rats with resection of the distal small intestine.  Beneficial effect of goat milk.  J Dairy Sci 86: 2958-2966.

Nestars T, Castro JD, Alferex MJM, Lopez-Aliaga I, Barrionuevo M & Campos MS (2008) Calcium-enriched goat milk, in comparison with similarly enriched cow milk, favours magnesium bioavailability in rats with nutritional ferropenic anaemia. Journal of the Science of Food and Agriculture. 88:319-327.

Nestares T, Barrionuevo M, Díaz-Castro J, López-Aliaga I, Alférez MJ, Campos MS (2008) Calcium-enriched goats' milk aids recovery of iron status better than calcium-enriched cows' milk, in rats with nutritional ferropenic anaemia. J Dairy Res. 75:153-9.

Díaz-Castro J, Ramírez López-Frías M, Campos MS, López-Frías M, Alférez MJ, Nestares T, Ortega E, López-Aliaga I. (2011) Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency. J Dairy Sci. 94:2752-61.

The absorption efficiency of fat from goat milk was compared to cow milk fat in a double-blinded randomized study of 64 infants.  The infants in the study had digestive disorders and suffered from fat malabsorption due to gluten deficiency.  One group was randomized to a diet containing goat milk and butter and the other to cow milk and butter.  There was a 5% greater absorption of fat from the goat milk diet. 

A copy of the publication can be downloaded from

Goat milk is widely used by people with digestive problems and sensitivities to cow milk.   While goat milk cannot be considered hypoallergenic, several studies show that it does have a different allergenic burden compared to cow milk.  On average, five times more goat milk than cow milk was required to trigger an adverse reaction in children allergic to cow milk (Bellioni-Businco et al, 1999).  Animal studies show less severe reactions at the low levels of αs1-casein in goat milk (Hodgkinson et al. 2012, Bevilacqua et al, 2001).  In another study, only one animal developed allergy symptoms to goat milk compared to eight given cow milk immediately after weaning (Lara-Villoslada et al, 2004).  The authors concluded that goat milk is less likely to lead to development of allergy to milk proteins compared to cow milk when introduced immediately after weaning from breast milk.

Bellioni-Businco, B., Paganelli, R., Lucenti, P., Giampietro, P. G., Perborn, H. & Businco, L. (1999). Allergenicity of goat's milk in children with cow's milk allergy. Journal of Allergy and Clinical Immunology, 103, 1191-1194.

Bevilacqua, C., Martin, P., Candalh, C., Fauquant, J., Piot, M., Roucayrol, A. M., Pilla, F. & Heyman, M. (2001). Goats' milk of defective alpha (s1)-casein genotype decreases intestinal and systemic sensitization to beta-lactoglobulin in guinea pigs. Journal of Dairy Research, 68, 217-227.

Hodgkinson, A. J., McDonald, N. A., Kivits, L. J., Hurford, D. R., Fahey, S. & Prosser, C. (2012). Allergic responses induced by goat milk alphaS1-casein in a murine model of gastrointestinal atopy. J Dairy Sci, 95, 83-90.

Lara-Villoslada F, Olivares M, Jimenez J, Boza J, Xaus J (2004) Goat milk is less immunogenic than cow milk in a murine model of atopy. J Pediatr Gastroenterol Nutr 39: 354-360.

It has been known for some time that human milk contains a complex array and amount of oligosaccharides.  These oligosaccharides have a wide range of beneficial functions.  These include a source of nourishment for pro-biotic microbes within the infant’s gut, prevention of gastro-intestinal infection of pathogenic bacteria and possibly infant brain development.   One study suggested that goat milk contains between 250 to 300 mg/L oligosaccharides (Martinez-Ferez et al 2006), which is lower than human milk, but 4-5 times higher than the content in cow milk.  In a new study published in 2013, goat milk samples were found to contain nearly 4 fold higher levels than these earlier measurements at 1.17 g/L (Meyrand et al 2013).  Although the amount of oligosaccharides measured in goat milk were still lower than the amount in human milk, the oligosaccharides found in goat milk shared similar structural elements critical to the bioactivity of human milk oligosaccharides.  These findings led the authors to conclude that goat milk represents a potential source of complex oligosaccharides for use in functional food products.

Martinez-Ferez A, Rudloff S, Guadix A, Henkel CA, Pohlentz G, Boza JJ, Guadix EM, Kunz C, (2006) Goat’s milk as a natural source of lactose-derived oligosaccharides: Isolation by membrane technology. International Dairy Journal 16, 173-181.
Meyrand M, Dallasa DC, Caillat H, Bouvierd F, Martine P, Barile D (2013) Comparison of milk oligosaccharides between goats with and without the genetic ability to synthesize alphas1-casein. Small Ruminant Research 113, 411–420.

Casein phoshopeptides are a group of peptides derived from casein containing a high content of phosphate groups.  Casein phoshopeptides are released from casein by the digestion process within the gastrointestinal tract.  The primary benefit of casein phosphopeptides is that they bind minerals such as calcium, iron or zinc, increasing the solubility and absorption of these minerals.  Scientists in USA have completed a comprehensive analysis of the types of casein phosphopeptides in goat milk (Olumee-Shabon & Boehmer, 2013).  Eight different casein phosphopeptides were characterised. 

Olumee-Shabon Z and Boehmer JL (2013) Detection of casein phosphopeptides in goat milk. Journal of Proteome Research 12, 3034−3041.

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