None listed
Conditions
Brief summary
At present there is debate surrounding the effects of the A1 variant (A1) of the beta-casein protein contained in bovine milk compared to the progenitor A2 variant (A2) in terms of potential health outcomes. However, there is evidence to suggest that the beta-casein composition of milk can have an impact on gastrointestinal symptoms of intolerance which may be due to exposure to A1 beta-casein derived digestion products. Given the Australian Dietary Guidelines recommend the consumption of at least 2-3serves of dairy foods per day, the effects of milk variety on digestive function and exposure to beta-casein digestion products is important and warrants investigation. Most available milk and milk products contain comparable amounts of both A1 and A2, protein variants which are reported to have potential differences in bioactivity upon digestion. This stems from the release of the seven amino acid opioid peptide, termed beta-casomorphin-7 (BCM-7) from the digestion of A1 but not A2 beta-casein. However, further research is required to demonstrate clearly any differential in vivo effects between A1 and A2 beta-casein consumption on biological responses, including those associated with gastrointestinal symptoms of milk intolerance. The general aim of this blinded, cross-over trial is to demonstrate that A2 beta-casein containing milk will have a neutral effect on gastrointestinal symptoms and exposure to BCM-7 relative to A1 beta-casein containing milk.
Interventions
This will be a randomised, crossover study over an 8 week period consisting of 2 weeks of an initial washout. Following washout, 40 participants will be randomised to either the A1 milk or A2 milk group (Crossover 1), with 20 in each group. This is then followed by another 2 weeks washout after which Subjects will then start the alternative A1 or A2 milk Intervention for another 2 weeks intervention (crossover2).
During washout, participants will consume their normal diet (excluding all dair
This will be a randomised, crossover study over an 8 week period consisting of 2 weeks of an initial washout. Following washout, 40 participants will be randomised to either the A1 milk or A2 milk group (Crossover 1), with 20 in each group. This is then followed by another 2 weeks washout after which Subjects will then start the alternative A1 or A2 milk Intervention for another 2 weeks intervention (crossover2). During washout, participants will consume their normal diet (excluding all dairy) and use rice milk and rice yoghurt alternatives to replace habitual daily dairy intake. Intervention consists of either: 1) a normal diet (excluding all dairy) + 750mL A2 beta-casein protein containing milk consumed in 3 serves daily (~7-8g A2 type beta-casein/day) or 2) Normal diet (excluding all dairy) + 750mL A1 containing milk per day, which is equivalent to ~7-8g A1 type beta-casein/day; Milk will be given as UHT long life, skim milk (A2 Dairy Products Australia) Average composition: energy 189kJ/100mL total protein 3.1g/100mL total fat 0.1g/100mL carbohydrate (including lactose) 5.2g/100mL
Sponsors
Curtin University of Technology
Study design
Allocation
Randomised controlled trial
Intervention model
Crossover
Primary purpose
Treatment
Masking
Blinded (masking used)
Eligibility
Sex/Gender
All
Age
18 Years to 65 Years
Healthy volunteers
Yes
Inclusion criteria
Caucasian Do not drink more than 1 serve milk/day Those who report lactose intolerance but have not received medial diagnosis Willing to consume milk for 8 weeks Able to sign and understand informed consent
Exclusion criteria
Milk allergy Diagnosed lactose intolerance Pregnancy and lactation Cardiovascular event in the last 6 months Current, habitual opioid consumption Antibiotic treatment within the last 8 weeks prior to screening Immunosuppressive medications or anti-inflammatory drugs within the last 4 weeks prior to screening
Outcome results
None listed