Feedstuffs is part of the Informa Markets Division of Informa PLC

This site is operated by a business or businesses owned by Informa PLC and all copyright resides with them. Informa PLC's registered office is 5 Howick Place, London SW1P 1WG. Registered in England and Wales. Number 8860726.

Letter to the editor

Letter to the editor
RE: Research looks at benefits of supplementing cow milk with plant protein.

Dec 17, 2021

To the Editor

RE: Research looks at benefits of supplementing cow milk with plant protein. Feedstuffs, Dec 15, 2021.

Ohio State researchers develop a method to incorporate plant-based proteins with milk to produce a high protein, multisourced, functional food product1.  

1Krentz, et al. 2021. Use of casein micelles to improve the solubility of hydrophobic pea proteins in aqueous solution vial low- temperature homogenization. J. Dairy Sci. (in press).

From my perspective there are a couple of concerns with this study.  First, the stated and implied justifications for this research are misleading.  The authors state “the dairy industry struggles to maintain consumer attention in the midst of declining fluid milk sales”.  It is true that total fluid milk consumption (in the US) has been declining since the mid 1970’s (USDA/ARS, 2021), however, fluid consumption has leveled off in recent years and there actually has been an uptick in whole milk sales.  Despite lower fluid milk consumption, per capita dairy product consumption actually increased by over 100 lb per year (fat equivalent basis) since 1975 led by large increases in cheese and yogurt consumption.  Another stated justification was that “the demand for plant based protein is growing due to consumers’ desires for high protein health benefits and environmentally conscious products.”  Consumers may have the desire for these attributes but the implication that plant based proteins promote health benefits and are more environmentally ‘conscious’ than animal based proteins is highly debatable. It’s unfortunate that the researchers latched on to these narratives (the dairy industry is in decline, and we can offer a healthier more environmentally friendly solution) to justify this study.

Secondly, pea protein, was chosen as the plant based protein for this study, because it “has become fairly popular due to its branched AA composition that assist in muscle synthesis and expansion.” In as much as this vegetable protein would partially replace milk protein through the process described, the question can be raised, would this increase the nutritional value of milk?  Table 1 compares the essential amino acid (EAA) composition of pea versus milk protein based on true illeal digestibility (accounting for both differences in EAA composition and digestibility). Pea protein does have an EAA content that meet WHO/FAO requirements (WHO/FAO/UNU Expert Consultation, 2007). However, pea protein is lower in all EAA compared to milk protein.  Leucine is the branch chain amino acid that has been shown to activate the protein synthetic machinery.  Digestible leucine content of pea protein is only 64% of milk protein.  Once activated, all EAA are required for muscle protein synthesis. The shortage of one or more specific amino acids (e.g., methionine in the case of pea protein) could compromise sustained muscle protein synthesis rates (Gorissen et al. Amino Acids 2018).  Adding pea protein to milk would reduce its nutritional value in terms of digestible EAA.  

 

 

Table 1. True Ileal Digestible Amino Acid Content mg/g Pea versus Milk Protein

Amino Acid

Pea

Milk

Pea % of Milk

Threonine

23.8

41.3

58

Methionine

2.8

25.8

11

Phenylalanine

35.6

43.5

82

Histidine

16.2

23.4

69

Lysine

47.6

72.6

66

Valine

26.0

41.1

63

Isoleucine

22.7

32.7

26

Leucine

55.6

86.2

64

References: Gorissen et al. Amino Acids 2018. 50:1685.  CVB Feed Tables 2016.

Thus, this combined pea/milk protein combination would lower the nutritional value of milk.

In summary, the justification for this research, suggesting a failing dairy industry “struggling to maintain consumer attention” and implying that a plant based protein addition to milk would be more environmentally ‘conscious’ and healthier is very questionable. Whether the resulting product(s) would increase dairy consumption is unknown, but they certainly would not improve nutritional value over milk alone.   Researchers can be commended for developing a novel method of incorporating insoluble vegetable proteins into milk casein micelles and perhaps this could be a viable way to blend milk protein into plant based beverages and enhance their EAA profile, but not the other way around.

James Aldrich, Ph.D.
CSA Animal Nutrition
Dayton OH
 

 

 

TAGS: Commentary
Hide comments
account-default-image

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish