Title MSG Intake May Increase Probability of Sleep Disordered Breathing and Snoring
Clinical Question In a non-overweight adult, does MSG intake increase the risk of sleep apnea?
Clinical Bottom Line MSG intake is positively correlated with sleep-disordered breathing and snoring, although no correlation was found between MSG intake and a witnessed sleep apnea event. More rigorous studies need to be done for true clinical applicability.
Best Evidence  
PubMed ID Author / Year Patient Group Study type
(level of evidence)
23274090Shi/2013509 men, 718 womenRetrospective Cohort Study
Key resultsThe study included patients who were re-contacted for follow-up interviews and clinical exams after a 2002 study on food intake and sleep duration; participants who had moved cities, did not participate in a follow-up interview, missed the clinical exam, had extreme weight changes or were missing initial values for MSG intake were excluded. Each participant was interviewed in their home and questioned regarding frequency of sleep disturbances, witnessed sleep apnea events, and degree of snoring. This information was used to calculate a Sleep Disordered Breathing (SDB) probability score. Baseline MSG intake was determined through a questionnaire and daily food logs to confirm information given in the questionnaire. MSG intake was then divided into quartiles. Across those quartiles, MSG intake was positively associated with a high SDB probability score and snoring. The percentage of participants with a high SDB probability score increased from 15.1% to 25.9% (P=0.010) across MSG intake quartiles. The mean probability for SDB also increased significantly across quartiles (P<0.001). In men, snoring increased from 46.5% to 54.0% (P=0.110); in women snoring increased 18.1% to 28.2% (P=0.024); and in men and women combined it increased from 27.5% to 42.0% (P<0.001). No link was found between MSG intake and a witnessed sleep apnea event (defined as a specific sleep apneic event witnessed by a bedfellow).
Evidence Search "Sodium Glutamate"[Mesh] AND "Sleep Apnea Syndromes"[Mesh]
Comments on
The Evidence
Validity: This study relied on self-report for both MSG consumption and sleep behavior, a potential issue with its validity. In addition, the only objective measure of sleep apnea, a witnessed sleep apnea event, showed no positive correlation. MSG consumption per individual was determined by dividing the total amount of household MSG intake by the number of individuals in the household, and then adjusting for proportion of household energy intake. This method could over- or under-report MSG intake for individuals. Moreover, this cohort study is relatively low on the evidence pyramid due to its retrospective nature and lack of control group.
Applicability This study found a correlation between MSG intake and sleep-disordered breathing, an issue that affects 15%-20% of the population. However, because of the issues listed above, more rigorous studies need to be done to determine causation. In addition, this is one of the only studies available that examines this correlation, so practitioners should proceed with caution.
Specialty (General Dentistry) (Interprofessional CATs)
Keywords Sleep apnea, sleep disordered breathing, monosodium glutamate, MSG
ID# 3082
Date of submission 04/14/2016
E-mail sorensenm@Livemail.uthscsa.edu
Author McKenzie Sorensen
Co-author(s) John Rugh
Co-author(s) e-mail RUGH@uthscsa.edu
Faculty mentor Georgiana S. Gross, MPH
Faculty mentor e-mail GROSSG@uthscsa.edu
Basic Science Rationale
(Mechanisms that may account for and/or explain the clinical question, i.e. is the answer to the clinical question consistent with basic biological, physical and/or behavioral science principles, laws and research?)
None available
Comments and Evidence-Based Updates on the CAT
None available