Dietary Sodium Intake and Asthma: An Epidemiological and Clinical Review

T. D. Mickleborough; A. Fogarty


Int J Clin Pract. 2006;60(12):1616-1624. 

In This Article

Summary and Introduction


The changes in diet associated with the development of a more affluent lifestyle have been considered one of the environmental factors that may have contributed to the rise in the prevalence of asthma over the past few decades, and dietary sodium has been considered to be a dietary constituent which may be implicated in this phenomenon. The data presented in this review demonstrate that adoption of a low sodium diet for a period of 2-5 weeks may improve lung function and decrease bronchial reactivity in adults with asthma, while sodium loading appears to have a detrimental effect. Similarly, a low sodium diet maintained for 1-2 weeks decreases bronchoconstriction in response to exercise in individuals with asthma. There is no data as to the longer-term effect of a low sodium diet on either the prevalence or severity of asthma or on exercise-induced bronchoconstriction. As a low sodium diet has other beneficial health effects, it can be considered as a therapeutic option for adults with asthma, although it should be considered as an adjunctive intervention to supplement optimal pharmacological management of asthma and not as an alternative. If the relationship between higher sodium intake and increased prevalence and severity of asthma is causal, then there are potential population benefits for asthma as well as cardiovascular disease to be derived from public health measures to reduce sodium consumption.


The dramatic increase in the prevalence of asthma in the second half of the 20th Century has led to the search for environmental exposures that have driven this change. Diet is one of the environmental factors that have been considered to be potentially important, as dietary patterns have changed over this period and plausible biological mechanisms exist for many nutrients,[1] with dietary sodium being one of the first dietary factors to be considered to possibly modify the risk of asthma. We aim to review the current evidence of the effect of sodium intake on asthma and exercise-induced bronchoconstriction (EIB). The data come from two study designs, observational epidemiology which assesses the association of measures of sodium intake on the risk of asthma, and intervention studies, which look at the effect of manipulating dietary sodium intake on asthma-related outcome measures in participants with and without asthma. Generally, the former investigates the effect of sodium of prevalence of asthma, while the latter assess the effect on severity of asthma or bronchoconstriction.

For this review, the keywords: sodium, dietary salt and sodium chloride were coupled with the keywords: asthma, airway hyper-responsiveness, exercise-induced asthma and EIB, for a Medline®, EMBASE, Cochrane Central Register of Controlled Trials and SPORTDiscus search.


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