COPD: Effectiveness of Therapies (2007-2008)


Wuthrich B, Schmid A, Walther B, Sieber R.  Milk consumption does not lead to mucus production or occurrence of asthma.  J Am Coll Nutr 2005;24(6 Suppl):547S - 55S.


PubMed ID: 16373954
Study Design:
Narrative Review
R - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To examine the available evidence regarding the question of whether milk consumption leads to increased mucus formation and whether milk is related to the occurrence of asthma.

Inclusion Criteria:

Article inclusion criteria not described.

Exclusion Criteria:

Article exclusion criteria not described.

Description of Study Protocol:


Article selection methods not described.  Search terms used to locate articles not described.

Design:  Narrative Review 

Blinding used (if applicable):  Not applicable 

Intervention (if applicable):  Not applicable 

Statistical Analysis

Statistical analysis not completed.

Data Collection Summary:

Timing of Measurements

Not applicable.

Dependent Variables

  • Mucus production
  • Occurrence of asthma

Independent Variables

  • Milk and dairy consumption

Control Variables


Description of Actual Data Sample:

Initial N: 49 references included

Attrition (final N):  49

Age:   not mentioned

Ethnicity:  not mentioned

Other relevant demographics:


Location:  worldwide studies


Summary of Results:


Challenge Type Baseline 30 minutes 1 hour

7 hours

FEV1 - Cow's milk (L) 2.86 -0.09 -0.05 0.04

FEV1 - Placebo (L)





FEV1/FVC - Cow's milk (%)





FEV1/FVC - Placebo  (%) 81.8 -1.44 -1.44 -0.68


Other Findings

According to Australian studies, subjects perceived some parameters of mucus production to change after consumption of milk and soy-based beverages, but these effects were not specific to cows' milk because the soy-based milk drink with similar sensory characteristics produced the same changes.

In individuals inoculated with the common cold virus, milk intake was not associated with increased nasal secretions, symptoms of cough, nose symptoms or congestion.

Individuals who believe in the mucus and milk theory report more respiratory symptoms after drinking milk.

In some types of alternative medicine, people with bronchial asthma are advised not to eat mucus-forming foods, especially all kinds of dairy products.

In rare cases asthma can occur in patients with confirmed food allergy against cow's milk proteins.

People with asthma are sometimes advised to abstain from the consumption of dairy products, but research shows that consumption of milk does not significantly change various lung function parameters.

Limiting dairy food consumption can lead to low intake of many nutrients, including calcium.

Author Conclusion:

The belief that milk consumption leads to an increased mucus production is present among some members of the public.  The following conclusions can be drawn from the results of the different investigations:

1.  People who believe that milk increases mucus formation are more likely to report changes in sensory perceptions related to mucus after drinking milk than those who do not hold the same belief.

2.  In a double blind trial, symptoms of increased mucus formation were detected by healthy adults after consumption of both cows' milk and a non-milk beverage with similar sensory properties.

3.  Furthermore, persons who were convinced of mucus formation due to milk consumption showed more respiratory symptoms.  It is possible that aggregation after mixing of an emulsion such as milk with saliva can partly explain this sensation.

According to different investigations the consumption of milk does not seem to exacerbate the symptoms of asthma and a relationship between milk consumption and the occurrence of asthma cannot be established.  However, there are a few cases documented in which people with a cow's milk allergy presented with asthma-like symptoms.

Funding Source:
Reviewer Comments:

Article selection methods, search terms and inclusion/exclusion criteria not defined.

Quality Criteria Checklist: Review Articles
Relevance Questions
  1. Will the answer if true, have a direct bearing on the health of patients? Yes
  2. Is the outcome or topic something that patients/clients/population groups would care about? Yes
  3. Is the problem addressed in the review one that is relevant to dietetics practice? Yes
  4. Will the information, if true, require a change in practice? Yes
Validity Questions
  1. Was the question for the review clearly focused and appropriate? Yes
  2. Was the search strategy used to locate relevant studies comprehensive? Were the databases searched and the search termsused described? No
  3. Were explicit methods used to select studies to include in the review? Were inclusion/exclusion criteria specified andappropriate? Wereselectionmethods unbiased? No
  4. Was there an appraisal of the quality and validity of studies included in the review? Were appraisal methodsspecified,appropriate, andreproducible? No
  5. Were specific treatments/interventions/exposures described? Were treatments similar enough to be combined? Yes
  6. Was the outcome of interest clearly indicated? Were other potential harms and benefits considered? Yes
  7. Were processes for data abstraction, synthesis, and analysis described? Were they applied consistently acrossstudies and groups? Was thereappropriate use of qualitative and/or quantitative synthesis? Was variation in findings among studies analyzed? Were heterogeneity issued considered? If data from studies were aggregated for meta-analysis, was the procedure described? No
  8. Are the results clearly presented in narrative and/or quantitative terms? If summary statistics are used, are levels ofsignificance and/or confidence intervals included? Yes
  9. Are conclusions supported by results with biases and limitations taken into consideration? Are limitations ofthe review identified anddiscussed? Yes
  10. Was bias due to the review's funding or sponsorship unlikely? Yes