Administration of a sour taste during the early period of acute ischemic stroke had a beneficial effect on swallowing function in patients with dysphagia.
Key Findings
Results
Patients in the intervention group demonstrated significantly greater improvement in swallowing function compared with the control group at both day 7 and day 30 assessments.
The intervention group (n = 47) received 4 mL of room temperature lemon juice before breakfast, lunch, and dinner for 7 days.
The control group (n = 48) received 4 mL of room temperature water on the same schedule.
Swallowing function was assessed using the Gugging Swallowing Screen (GUSS) at baseline, day 7, and day 30.
The between-group difference in total GUSS scores at day 30 demonstrated a large effect size (r = 0.54, p < 0.001).
Results
No statistically significant difference between groups was observed in NIHSS stroke severity scores during follow-up.
Stroke severity was assessed using the National Institutes of Health Stroke Scale (NIHSS) as a secondary outcome.
All between-group comparisons of NIHSS scores were non-significant (all p > 0.05).
NIHSS was evaluated at the initial assessment, end of day 7, and day 30.
This indicates the swallowing improvement in the intervention group was not attributable to differential recovery in overall stroke severity.
Results
In both groups, swallowing function improved as stroke severity decreased over the follow-up period.
This pattern was observed across both the lemon juice intervention group and the water control group.
Assessments were conducted at baseline, day 7, and day 30.
The finding suggests that natural neurological recovery contributed to swallowing improvement in both groups, with additional benefit seen in the sour taste group.
Methods
The study enrolled 95 patients with confirmed ischemic stroke and dysphagia admitted to a university hospital neurology department.
The study was a randomized controlled trial design.
Participants were randomized to intervention (n = 47) or control (n = 48) groups.
The Standard Swallowing Test, GUSS, and NIHSS were all applied at baseline.
A p-value < 0.05 was used as the threshold for statistical significance.
The study was registered at ClinicalTrials.gov (NCT07400822).
Conclusions
Sour taste stimulation was identified as a practical, feasible, and complementary sensory intervention in post-stroke dysphagia management.
The intervention used 4 mL of room temperature lemon juice administered three times daily (before each meal) for 7 days.
The authors note that untreated swallowing disorders lead to increased morbidity and mortality due to inadequate nutrition, dehydration, and aspiration pneumonia.
The large effect size (r = 0.54) at day 30 supports clinical meaningfulness of the intervention.
The authors describe sour taste stimulation as an early-period intervention during acute ischemic stroke.
What This Means
This research suggests that giving stroke patients small amounts of lemon juice before meals may help them recover swallowing ability faster than giving them water alone. In this study, 95 patients who had recently experienced an ischemic stroke and were having trouble swallowing were randomly assigned to receive either 4 mL of lemon juice or 4 mL of water three times a day for one week. Swallowing ability was measured at the start of the study, after one week, and after one month using a validated clinical swallowing assessment tool called the Gugging Swallowing Screen.
The patients who received lemon juice showed significantly better swallowing function at both the one-week and one-month follow-up points compared to those who received water. The difference between the two groups at one month was described as having a 'large effect size,' meaning the improvement was clinically meaningful, not just statistically detectable. Importantly, the overall severity of the stroke (measured by a standard neurological scale) did not differ significantly between the two groups over time, suggesting the swallowing benefit was specifically related to the sour taste stimulation rather than simply recovering faster from the stroke overall.
Swallowing problems after stroke are a serious concern because they can lead to malnutrition, dehydration, and dangerous lung infections from accidentally inhaling food or liquid. This research suggests that sour taste stimulation — delivered simply and inexpensively through lemon juice — could be a practical add-on approach to help rehabilitate swallowing in stroke patients during the early recovery period. The intervention requires further study in larger and more diverse populations before broad clinical adoption, but the findings support exploring sensory-based strategies as complements to standard dysphagia care.
Gunes A, Erol O, Kehaya S. (2026). Effect of Sour Taste on Swallowing Function of Patients With Dysphagia After Acute Ischemic Stroke: A Randomized Controlled Trial.. Brain and behavior. https://doi.org/10.1002/brb3.71680