The investigators will recruit 45 fluid milk avoiding adults to participate in a five-week double-blind, double-crossover study in which the physiological responses to increasing doses of lactose-free (A1-rich milk), A2 milk, and lactose-free A2 milk will be explored.
Dairy provides essential nutrients and dairy products and are among the best quality and bioavailable protein sources available to humans. Milk protein allergy is extremely rare outside of childhood, and lactose intolerance is highly variable among ethnicities. Nonetheless, many adults avoid fluid milk and dairy products unnecessarily. Recent studies suggest that dairy intolerant individuals are having gastrointestinal reactions specifically to the bioactive metabolites (specifically, beta-casomorphin-7\[BCM-7\]) of casein protein subtype A1, and consuming milk void of A1 and rich in A2 casein alleviates symptoms. The investigators will recruit 45 fluid milk avoiding adults to participate in a five-week double-blind, double-crossover study in which physiological responses to increasing doses of lactose-free (A1-rich milk), A2 milk, and lactose-free A2 milk will be explored. Enrollment assessments will include a comprehensive metabolic panel, diet history, and medical history questionnaires. Stool samples will be collected at the beginning and end of each of the 3 test phases (6 total samples per participant). Each test phase will last 6 days long, during which participants will receive increased doses of casein every 2 days. On Day 1, participants will receive 50mg casein/kg/bw (\~125ml milk). On Day 3, participants will receive 100mg casein/kg/bw (\~250ml milk). On Day 5, participants will received 200mg casein/kg/bw (\~500ml milk). During test phases, breath hydrogen and methane will be measured every thirty minutes for three hours, and blood glucose will be measured every thirty minutes for two hours. Gastrointestinal symptoms will be assessed with visual analog scales for the following 24 hours. There will be a 7-10 day wash out period in between test phases.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
TRIPLE
Enrollment
48
Participants will receive conventional lactose-free cow's milk as follows: On Day 1, participants will receive 50mg casein/kg/bw (\~125ml milk). On Day 3, participants will receive 100mg casein/kg/bw (\~250ml milk). On Day 5, participants will received 200mg casein/kg/bw (\~500ml milk). During test phases, breath hydrogen and methane will be measured every thirty minutes for three hours, and blood glucose will be measured every thirty minutes for two hours. Gastrointestinal symptoms will be assessed with visual analog scales for the following 24 hours. There will be a 7-10 day wash out period in between test phases.
Participants will receive nonconventional (A2) cow's milk as follows: On Day 1, participants will receive 50mg casein/kg/bw (\~125ml milk). On Day 3, participants will receive 100mg casein/kg/bw (\~250ml milk). On Day 5, participants will received 200mg casein/kg/bw (\~500ml milk). During test phases, breath hydrogen and methane will be measured every thirty minutes for three hours, and blood glucose will be measured every thirty minutes for two hours. Gastrointestinal symptoms will be assessed with visual analog scales for the following 24 hours. There will be a 7-10 day wash out period in between test phases.
Auburn University
Auburn, Alabama, United States
Gastrointestinal Distress Scores
Changes in gastrointestinal distress measured via visual analog scales that range from 0 (no symptoms) to 100 cm (severe symptoms). Lower values are optimal.
Time frame: 24 hours after each sample challenge
Breath Hydrogen (ppm)
Breath hydrogen will be measured via QuinTron BreathTracker SC Analyzer every 30 minutes for three hours beginning immediately prior to each sample challenge. Lower levels are optimal.
Time frame: Three hours after each sample challenge
Breath Methane (ppm)
Breath methane will be measured via QuinTron BreathTracker SC Analyzer every 30 minutes for three hours beginning immediately prior to each sample challenge. Lower levels are optimal.
Time frame: Three hours after each sample challenge
Blood Glucose (mg/dl)
Capillary finger sticks will determine blood glucose levels for two hours beginning immediately prior to each sample challenge. Minimal deviations from baseline are optimal.
Time frame: Two hours after each sample challenge
Stool microbiome composition
16S changes in microbiome alpha diversity. Higher levels are optimal.
Time frame: One week after each sample challenge
Stool Beta-casomorphin-7 (BCM-7)
Fecal samples preserved in aqueous solution will be analyzed for casein metabolite, BCM-7. Lower levels are optimal.
Time frame: One week after each sample challenge
Stool intestinal fatty acid binding protein (I-FABP)
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Participants will receive nonconventional (A2) lactose-free cow's milk as follows: On Day 1, participants will receive 50mg casein/kg/bw (\~125ml milk). On Day 3, participants will receive 100mg casein/kg/bw (\~250ml milk). On Day 5, participants will received 200mg casein/kg/bw (\~500ml milk). During test phases, breath hydrogen and methane will be measured every thirty minutes for three hours, and blood glucose will be measured every thirty minutes for two hours. Gastrointestinal symptoms will be assessed with visual analog scales for the following 24 hours. There will be a 7-10 day wash out period in between test phases.
Fecal samples preserved in aqueous solution will be analyzed for intestinal permeability marker, I-FABP. Lower levels are optimal.
Time frame: One week after each sample challenge