Beneficial Effects of Ginger Extract on Eye Fatigue and Shoulder Stiffness: A Randomized, Double-Blind, and Placebo-Controlled Parallel Study

This study aimed to assess ginger extract's impact on ocular and peripheral blood flow and its potential to alleviate eye fatigue and shoulder stiffness. This study included 100 healthy individuals aged 20-73 years with eye fatigue and shoulder stiffness. Participants were randomly assigned to receive either placebo capsules or ginger extract capsules daily for eight weeks. Ocular blood flow, peripheral blood flow, eye fatigue (visual analog scale [VAS]), shoulder stiffness (VAS), body warmth (VAS), and shoulder muscle stiffness were assessed at weeks 0, 4, and 8, respectively. No improvement in ocular blood flow was observed under the study conditions. Conversely, peripheral blood flow in deep areas was enhanced in females (p = 0.033). Subgroup analysis by age (>= 51 or <51 years) revealed that ginger's effect on enhancing peripheral blood flow in deep vessels was restricted in females under 51 (p = 0.017). Similarly, subjective complaints of eye fatigue and shoulder stiffness were improved by ginger consumption in females under 51. Body warmth was favorably changed significantly in males >= 51 years due to ginger consumption. The muscle stiffness showed no statistically significant changes. In conclusion, ginger consumption reduces eye fatigue and shoulder stiffness by enhancing peripheral blood flow in relatively young females.