Low-Dose Oral Ginger Improves Daily Symptom Scores in Asthma

Abstract

Background/Objective: A significant number of individuals with asthma have poorly controlled daily symptoms and utilize dietary supplements such as ginger in a quest for improved symptom control; however, its effectiveness at improving the control of symptoms is unproven. We questioned whether low-dose oral ginger would improve subjective and objective measurements of asthma control in mild-to-moderate asthmatics. Methods: We performed a randomized, placebo-controlled, double-blinded study of a low dose (1 g twice daily) of a dietary supplement of ginger in 32 mild-to-moderate uncontrolled asthmatics over a 2-month trial period while maintaining daily conventional asthma therapies. The planned primary outcomes included an increased tolerance to inhaled methacholine and decreased concentrations of fractional excretion of exhaled nitric oxide (FeNO). Secondary planned outcomes included measurements of asthma control by the Asthma Control Test (ACT), a 2-week symptom recall test, and the Juniper mini Asthma Quality of Life Questionnaire (AQLQ), and blood eosinophils and asthma-associated cytokines. Results: Exhaled nitric oxide or blood eosinophils were not changed by oral ginger. However, three different measures of asthma symptom control were improved by the 28-day time point of oral ginger. Asthma-associated serum cytokines (IL-13 and IL-17A) were modulated by oral ginger. Conclusions: This is the first demonstration that a small daily dose of a dietary supplement of ginger may improve asthma symptoms and reduce inflammation in human asthmatics. These findings support the need for additional studies using larger doses of ginger in specific endotypes of asthmatics that may identify a novel therapeutic for asthma.

Keywords: 2-week symptom recall; AQLQ; asthma control test; cytokines; eosinophils; exhaled nitric oxide; methacholine.

Figure 1

Consort flow diagram of subjects screened and randomized.

Figure 2

Exhaled fraction of nitric oxide (FeNO) and blood eosinophils were measured at the randomization visit (visit 3) and after 28 days (visit 4) or 56 days (visit 5) of study drug. (A,B) There were no statistically significant changes in FeNO across the study visits in either the ginger (n = 20) or placebo (n = 12) groups. There were no statistically significant changes in (C,D) total or (E,F) the percentages of blood eosinophils across the study visits in either the ginger (n = 20) or placebo (n = 11–12) groups.

Figure 3

Asthma symptom scores were recorded by three methods (Asthma Control Test (ACT), 2-week recall score, and mini Asthma Quality of Life Questionnaire (AQLQ)) at the randomization visit (visit 3) and after 28 days (visit 4) or 56 days (visit 5) in subjects randomized to ginger (n = 20) or placebo (n = 12). (A) Ginger significantly improved scores on the asthma control test (ACT) between visits 4 and 5 (* p = 0.019). (B) Placebo also significantly reduced ACT scores between visits 3 to 5 (* p = 0.006) and between visits 4 to 5 (* p = 0.012). (C) Ginger improved the two week asthma symptom recall score between visits 3 to 4 (* p = 0.012) and between visits 3 to 5 (* p = 0.040). (D) Placebo had no effect on 2 week asthma symptom recall scores. (E) Ginger improve Asthma Quality of Life scores between visits 3 to 4 (* p = 0.033) and between visits 3 to 5 (*** p = 0.001). (F) Placebo had smaller effects on the Asthma Quality of Life scores between visits 3 to 4 (* p = 0.036) and visits 3 to 5 (* p = 0.011) compared to ginger.

Figure 4

Serum cytokines (IL-4, IL-5, IL-13, and IL-17A) in study subjects at the randomization visit (visit 3) and after 28 days (visit 4) or 56 days (visit 5) of study drug. (A,B) IL-4 was not different in either the ginger or placebo group comparing visits 3 to 4 or visits 3 to 5. (C,D) IL-5 was not different in either the ginger or placebo group comparing visits 3 to 4 or visits 3 to 5. (E) IL-13 was significantly decreased in the ginger group (* p = 0.03) between visits 3 to 4 and did not decrease further between visits 4 to 5. (F) Placebo had no effect on IL-13 levels comparing visits 3 to 4 or visits 3 to 5. (G) IL-17A was significantly decreased in the ginger group between visits 3 to 4 (* p = 0.025) and did not decrease further between visits 4 to 5. (H) Placebo had no effect on IL-17A levels comparing visits 3 to 4 or visits 3 to 5.

Figure 5

Clinical protocol timeline. Asthmatics were screened by baseline spirometry and response to β-agonist inhalation, with inadequate asthma symptom control defined as an Asthma Control Test (ACT) of 19 or less. Fractional exhaled nitric oxide (FeNO), methacholine bronchoprovocation, blood samples, and symptom scores were measured over 56 days.