The overall evidence suggests that milk products do not increase the risk of developing asthma or exacerbate asthma symptoms. In fact, emerging evidence suggests that regular-fat dairy products may decrease the risk of asthma and/or improve asthma symptoms.
- Milk products do not increase the risk of developing asthma nor do they have any adverse effects on asthma control;
- Regular fat dairy products such as whole milk, regular-fat yogurt, regular-fat cheese and butter may play a protective role in the development and/or control of asthma;
- Components in dairy products that may be beneficial include fatty acids, calcium and vitamin D.
Asthma is a chronic inflammation of the lining of the airways of the lungs and has several triggers which can vary with individuals.1 Food allergies may trigger asthma or worsen asthma symptoms.1 With regards to milk allergies, the incidence among infants is estimated to be about 2-3%, and tends to be outgrown before age 3 so that less than 0.5% of adults are estimated to be affected.2 It is important for studies to take food allergies into account when assessing the role of certain foods in asthma development and control. Unfortunately, this isn’t always the case which may contribute to confounding of results.
A double-blind randomized controlled trial explored whether dairy products induce bronchoconstriction in adults with asthma.3 Twenty adults were assigned to drink 300 ml of cow’s milk or 300 ml of rice beverage (placebo). There were no differences between the groups for standard respiratory measures such as forced expiratory volume and peak expiratory flow.
Another randomized controlled trial examined the effects of milk on bronchial airflow, measured by standard spirometry in 25 adults with mild asthma.4 Participants in this double-blind crossover study were randomly assigned to ingest a solution containing cow’s milk powder or a placebo solution. There were no important differences in pulmonary function results between the two groups.
A prospective cohort study of 61,909 pregnant women examined the relationship between dairy intake during pregnancy and the development of asthma in their offspring.5 The authors found a “suggestive protective association” for maternal consumption of whole milk and regular-fat yogurt and infant asthma while maternal intake of low-fat yogurt was suggestive of increased risk of child asthma.
Two prospective studies6,7 explored maternal dietary intakes during pregnancy and/or lactation and asthma development in their children:
- Consumption of milk, butter and total milk products during pregnancy and lactation was not associated with increased risk of asthma;
- Margarine consumption during lactation was associated with an increased risk of asthma by 96%;
- Higher intake of saturated fat and palmitic acid was found to have a protective association with asthma (45% to 49% decreased risk, respectively);
- Lower arachidonic acid (n-6 polyunsaturated fat) intakes during pregnancy had a protective association with risk of asthma.
Another prospective study examined associations between maternal consumption of dairy products, calcium and vitamin D during pregnancy and wheeze in their children at 16 to 24 months.8 This study, including 763 mother-child pairs, suggests protective roles against wheeze, a common sign of asthma in children:
- Higher consumption of total dairy products, milk, cheese and calcium during pregnancy was associated with a decreased risk of wheeze in their children;
- Consumption of full-fat, but not low-fat, milk was related to a reduced risk of wheeze;
- Higher vitamin D intake during pregnancy was also associated with a reduced risk of childhood wheeze.
A study comprised of 723 children between 8 and 10 years, 246 of whom were diagnosed with asthma, found that infrequent milk consumption (< 2 times/week) doubled the risk of asthma in girls.9 While overweight status alone was associated with a 39% increased risk of asthma, the combination of infrequent milk consumption and overweight was associated with a 3.6-fold increase in the risk of asthma in girls.
A longitudinal study of 696 newborns that were part of the "Study on the Prevention of Allergy in Children in Europe" (SPACE) looked at milk consumption and asthma development up to age 3.10 Milk consumption was not associated with asthma development.
Data from 2,978 children participating in the PIAMA birth cohort study11 revealed that daily consumption of regular-fat milk and butter were associated with a reduced risk of asthma compared to consumption of less than once a week. There was no association for reduced fat milk.
A review paper by Alwarith et al.12 published in Nutrition Reviews examined the association of various dietary factors in the development and control of asthma in children and adults. However, a critical analysis reveals several important weaknesses and limitations with this review as it pertains to milk products and asthma.
The components of milk products that could play a beneficial role in the etiology and control of asthma include fatty acids, calcium and vitamin D.
Data from a large U.S. national study (NHANES III) showed that lower serum vitamin D levels are associated with an increased risk of upper respiratory tract infections; and, that the burden of respiratory infections associated with lower serum vitamin D levels appears to be even greater in those with chronic respiratory diseases such as asthma and COPD.13
Milk products are not associated with an increased risk of asthma or adverse effects on control of asthma unless a person is allergic to milk protein and develops asthma symptoms as a result.
Emerging scientific evidence indicates that the consumption of regular-fat milk products may reduce the risk of asthma, but further research is needed to provide more definitive answers, particularly regarding the role of specific milk products.
More studies are also needed to clarify how specific fatty acids, calcium and vitamin D may decrease the risk of asthma and/or improve asthma symptoms.
- Asthma Canada. Frequently Asked Questions. www.Asthma.ca; Accessed 30 June 2021.
- Knol E et al. Management of cow’s milk allergy from an immunological perspective: what are the options? Nutrients 2019;11:2734.
- Woods RK et al. Do dairy products induce bronchoconstriction in adults with asthma? J Allergy Clin Immunol 1998;101: 45-50.
- Nguyen MT. Effect of cow milk on pulmonary function in atopic asthmatic patients. Ann Allergy 1997;79: 62-64.
- Maslova E et al. Low-fat yoghurt intake in pregnancy associated with increased child asthma and allergic rhinitis risk: a prospective cohort study. J Nutr Sci 2012;1: e5.
- Lumia M et al. Maternal dietary fat and fatty acid intake during lactation and the risk of asthma in the offspring. Acta Paediatr 2012;101: e337-343.
- Lumia M et al. Dietary fatty acid composition during pregnancy and the risk of asthma in the offspring. Pediatr Allergy Immunol 2011; 22: 827-835.
- Mlyake Y et al. Dairy food, calcium and vitamin D intake in pregnancy, and wheeze and eczema in infants. Eur Respir J 2010;35: 1228-1234.
- Mai XM et al. Infrequent milk consumption plus being overweight may have great risk for asthma in girls. Allergy 2007;62: 1295-1301.
- Chris M et al. Cow's Milk Exposure and Asthma in a Newborn Cohort: Repeated Ascertainment Indicates Reverse Causation. J Asthma 2007;44(2):99-105.
- Wijga AH et al. Association of consumption of products containing milk fat with reduced asthma risk in pre-school children: the PIAMA birth cohort study. Thorax 2003;58:567-572.
- Alwarith J et al. The role of nutrition in asthma prevention and treatment. Nutrition Reviews 2020; doi: 10.1093/nutrit/nuaa005.
- Ginde A et al. Association between serum 25-hydroxyvitamin D level and upper respiratory tract infection in the Third National Health and Nutrition Examination Survey. Arch Intern Med 2009;169(4): 384-390.