Effects of A2 milk (compared to regular milk) on asthma symptoms, inflammation and exercise performance in athletes with asthma-related conditions

The effect of A2 milk on exercise performance, inflammation and severity of exercise induced bronchospasm (EIB) in athletes with asthma-related conditions: a randomised crossover study

Status

Active, not recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN29968077

Enrollment

Registered

2017-08-22

Start date

2017-09-01

Completion date

Unknown

Last updated

2020-07-20

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Exercise performance and airway health in athletes/physically active adults with asthma/asthma-related conditions or exercise-induced bronchospasm (EIB) Respiratory

Interventions

Each participant will be required to swap their usual milk with milk provided by the trialists over two 2-week periods. On one occasion this will be regular cow’s milk (control condition) and on anoth

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: 1. Ability to consent to the research 2. Prior clinician-based diagnosis of asthma 3. Males and females 4. 18 – 45 years 5. Engage in regular endurance training (at least three times per week) 6. Normal resting Forced Expiratory Volume in One Second (FEV1); defined as greater than 80% of predicted value

Exclusion criteria

Exclusion criteria: 1. Chest infection within the past 4 weeks, or any other illness within the past 2 weeks 2. Fall in FEV1 >50% from baseline following exercise challenge 3. Baseline FEV1 of < 80% of predicted 4. Respiratory conditions (other than asthma/EIB) e.g. COPD 5. Cardiovascular conditions: 5.1. Coronary artery disease 5.2. High blood pressure 5.3. Heart failure 5.4. Diagnosed abnormality of heart rhythm 6. Metabolic diseases: 6.1. Type 1 diabetes 6.2. Type 2 diabetes 6.3. Pre-diabetes 7. Daily use of oral corticosteroids 8. Hospitalisation due to asthma in the six months prior to study commencement 9. Injury or conditions that limit mobility 10. Pregnancy 11. Known allergy or intolerance to milk or dairy 12. Does not regularly consume milk

Design outcomes

Primary

Measure	Time frame
All of the following measures will be assessed on 3 separate occasions over the study period - once at at baseline and once after each 2-week period: 1. Eucapnic Voluntary Hyperpnea (EVH) challenge with lung function testing (maximal flow-volume loop method) before and after EVH challenge test. The lung function test will be performed before and at 3, 5, 7, 10, and 15 min post-EVH challenge 2. Urine levels of 9a,11ß-prostaglandin and Clara cell protein (CC16) will be assessed in samples collected before and after (~1 h) EVH challenge by enzyme-linked immunosorbent assay (ELISA) method 3. Exhaled Nitric Oxide levels before and after (1 h) EVH challenge using a exhaled breath gas analyser	—

Measure

Time frame

All of the following measures will be assessed on 3 separate occasions over the study period - once at at baseline and once after each 2-week period: 1. Eucapnic Voluntary Hyperpnea (EVH) challenge with lung function testing (maximal flow-volume loop method) before and after EVH challenge test. The lung function test will be performed before and at 3, 5, 7, 10, and 15 min post-EVH challenge 2. Urine levels of 9a,11ß-prostaglandin and Clara cell protein (CC16) will be assessed in samples collected before and after (~1 h) EVH challenge by enzyme-linked immunosorbent assay (ELISA) method 3. Exhaled Nitric Oxide levels before and after (1 h) EVH challenge using a exhaled breath gas analyser

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Secondary

Measure	Time frame
1. To determine whether switching to A2 milk improves markers of inflammation, immune function and intestinal barrier integrity/intestinal epithelial cell damage markers: On the day after the EVH challenge participants will undertake an exercise trial (treadmill running) consisting of 20 min at ~60% maximal aerobic capacity followed by a 3 km performance time-trial in which they must cover this distance as quickly as possible. The following will be assessed before, immediately-post and up to 1h post-exercise: 1. Blood markers of intestinal barrier integrity/cell damage (e.g. iFABP), immune markers and systemic inflammatory, stress and oxidative stress markers (e.g. differential white blood cell count (by automated haematology analyser), phagocyte oxidative burst (stimulated and unstimulated) (by chemiluminescence assay), plasma CRP, inflammatory cytokines, and saliva secretory IgA (by ELISA), glutathione, and lipid peroxidation markers (by ELISA and photometric assay methods) 2. Self-report gut symptoms logged in a questionnaire immediately post-exercise using a visual analogue scale (VAS) 3. Self-report gut symptoms logged in a questionnaire for one rest day and one normal exercise training day (in their normal training schedule), using a VAS, at the beginning and end of each 2-week study period. The Bristol stool scale (self-report) and a frequency log will also be recorded on these days 4. Plasma levels of dipeptidyl peptidase 4 (DPP4) and beta-casomorphin-7 may also be analysed by ELISA and HPLC methods (depending on equipment availability and access) 2. To determine whether switching to A2 milk improves exercise performance and/or physiological responses to exercise, the following measures will be used: 1. 3 km time-trial performance (completion time) 2. Gas exchange (VO2, VCO2) during exercise using a respiratory gas analyser	—

Measure

Time frame

1. To determine whether switching to A2 milk improves markers of inflammation, immune function and intestinal barrier integrity/intestinal epithelial cell damage markers: On the day after the EVH challenge participants will undertake an exercise trial (treadmill running) consisting of 20 min at ~60% maximal aerobic capacity followed by a 3 km performance time-trial in which they must cover this distance as quickly as possible. The following will be assessed before, immediately-post and up to 1h post-exercise: 1. Blood markers of intestinal barrier integrity/cell damage (e.g. iFABP), immune markers and systemic inflammatory, stress and oxidative stress markers (e.g. differential white blood cell count (by automated haematology analyser), phagocyte oxidative burst (stimulated and unstimulated) (by chemiluminescence assay), plasma CRP, inflammatory cytokines, and saliva secretory IgA (by ELISA), glutathione, and lipid peroxidation markers (by ELISA and photometric assay methods) 2. Self-report gut symptoms logged in a questionnaire immediately post-exercise using a visual analogue scale (VAS) 3. Self-report gut symptoms logged in a questionnaire for one rest day and one normal exercise training day (in their normal training schedule), using a VAS, at the beginning and end of each 2-week study period. The Bristol stool scale (self-report) and a frequency log will also be recorded on these days 4. Plasma levels of dipeptidyl peptidase 4 (DPP4) and beta-casomorphin-7 may also be analysed by ELISA and HPLC methods (depending on equipment availability and access) 2. To determine whether switching to A2 milk improves exercise performance and/or physiological responses to exercise, the following measures will be used: 1. 3 km time-trial performance (completion time) 2. Gas exchange (VO2, VCO2) during exercise using a respiratory gas analyser

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Countries

United Kingdom

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026