Host Institution

a2 Milk™ for gut comfort

Matthew Barnett, AgResearch Limited April 14th 2016

Overview

• a2 Milk™ – what’s the story? • Where does this project fit in? • What do we hope to achieve? • How are we going to do it?

a2 Milk™ – What’s the Story?

• Bovine milk has >200 different proteins • One of these is β-casein, which comprises 25-30% of

the total protein • There are several well-characterised variants in the β-

casein gene • Some of these result in changes to the protein

sequence, with possible functional consequences

a2 Milk™ – What’s the Story?

• Originally, all cows produced only A2 β-casein

• A1 β-casein mutation developed in some European dairy herds 5-10,000 years ago. This form is now the most widespread

• Today, most milk contains a mix of A1 and A2 protein types

• a2 milk™ products contain only the A2 form of β-casein

a2 Milk™ – What’s the Story? β-casomorphin-7 (BCM-7)

Figure adapted from Gobbetti et al. (2002). Crit Rev Food Sci Nutr 42(3):223-39, and Jinsmaa & Yoshikawa (1999) Peptides 23(8):957-62

a2 Milk™ – What’s the Story? β-casomorphin-7 (BCM-7)

Figure adapted from Gobbetti et al. (2002). Crit Rev Food Sci Nutr 42(3):223-39, and Jinsmaa & Yoshikawa (1999) Peptides 23(8):957-62

Human β-casein is like A2, not A1, bovine β-casein

• Human, goat and sheep β-casein proteins are comparable to A2 (not A1) protein in terms of structure around BCM-7 release

• Only 1-10% of the theoretical human equivalent comes from in vitro digestion of human β-casein

• Internal differences mean bovine BCM-7 is 10 x more potent (opioid receptor binding) than the theoretical human equivalent

T y r 6 0 - P r o 6 1 - P h e 6 2 - P r o 6 3 - G l y 6 4 - P r o 6 5 - l l e 6 6 - H i s 6 7

T y r 6 0 - P r o 6 1 - P h e 6 2 - P r o 6 3 - G l y 6 4 - P r o 6 5 - l l e 6 6 - P r o 6 7

T y r 5 1 - P r o 5 2 - P h e 5 3 - V a l 5 4 - G l u 5 5 - P r o 5 6 - l l e 5 7 - P r o 5 8

B o v i n e β - c a s e i n A 1

B o v i n e β - c a s e i n A 2

H u m a n β - c a s e i n

a2 Milk™ – What’s the Story?

a2 Milk™ – What’s the Story? • Interest started with epidemiological studies indicating

differential disease risk associated with A1 and A2 milk • More recent work in animals and humans has focused on

immediate effects (e.g., digestive comfort) – Consumers care about the “now” – Generally accepted that a healthy gut means better overall

health • Pre-clinical data shows differences resulting from consumption

of standard milk (i.e., containing A1 β-casein) and a2 milk™ (free of A1 β-casein) – Intestinal transit1 – Inflammatory response1,2

1Barnett et al. (2014). Int J Food Sci Nutr 65(6):720-7 2Ul Haq et al. (2013). Eur J Nutr 53(4):1039-49

a2 Milk™ – What’s the Story? • Human clinical data1 showing consumption of

standard vs. a2 milk™ may lead to differences in – Intestinal comfort – Intestinal physiology – Cognitive behaviour

• Mechanisms may relate to the release of different bioactive peptides – BCM-7 from A1 β-casein has been shown to trigger

inflammation in human cells in vitro2 – This needs to be consolidated by human studies

1Jianqin et al. (2016). Nutrition Journal 15:35 2Trivedi et al. (2014). J Nutr Biochem 25(10):1011-8

Where does this project fit in?

• Many consumers in Asia consider themselves to be “lactose intolerant”

• These consumers avoid consuming dairy products due to intestinal discomfort

• Recent data suggest this discomfort may be due to inflammation in the small intestine, which may in turn be a response to A1 β-casein

Where does this project fit in?

Jianqin et al. (2016). Nutrition Journal 15:35

• Evidence of increased intestinal discomfort in response to A1 milk compared with A2 milk

Where does this project fit in? • Evidence of inflammation in response to A1 milk

compared with A2 milk – Increased serum IL-4, IgG, IgE

How can we build on this evidence?

Jianqin et al. (2016). Nutrition Journal 15:35

What do we hope to achieve? • Generate evidence that some consumers who

currently avoid dairy can tolerate a2 Milk™ • Better understand the mechanisms through which

this (in)tolerance occurs • Contribute evidence for a health claim by the a2 Milk

Company • -> Increased dairy consumption in China

How are we going to do it?

• Test the hypothesis: “that a2 Milk™ does not induce adverse symptoms of gut discomfort in consumers with perceived lactose intolerance.”

How are we going to do it? Clinical studies, standard vs. a2 Milk™ • A range of outcome measures, including

– Self-reported intestinal symptoms/mood/appetite – Imaging of small intestine – Plasma

• Metabolites • Cytokines

– Breath volatile metabolites

How are we going to do it?

In vitro studies, purified and SGID A1 vs. A2 β-casein • How do these variants influence inflammatory

response? – Cytokine release from cells

• TNF-α (pro-inflammatory) • IL-10 (anti-inflammatory) • IL-4 (pro-inflammatory)

– miRNA release from cells • miRNAs related to inflammation

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Outcomes • Demonstrate health benefits of a2 Milk™-based

products for improving gut comfort

• Contribute to the a2 Milk Company’s mission:

“to pioneer the scientific understanding of a2 Milk™ so we can bring more people the pleasure and nutritional goodness that only comes from real and natural milk.”

Outcomes • Support the a2 Milk Company to submit a dossier

for a high-level health claim that meets NZ regulations, and those in key international export markets.

• Increased value to the NZ supply chain – Farmers

– Processors

– Ingredient manufacturers

Acknowledgements • HVN

• The a2 Milk Company Limited

• The University of Auckland

• “a2 Milk™ for Gut Comfort” Team – Shalome Bassett, David Cameron-Smith, Andrew Clarke, Li Day,

Karl Fraser, Amber Milan, Suzanne Simpson, Wayne Young

Cheers!