Description

Ghrelin, a hormone produced in the stomach, plays a key role in appetite, gut motility, and neuroprotection, particularly through its acylated form (AG). People with Parkinson's disease (PD) and those at high risk, such as individuals with REM Sleep Behaviour Disorder (RBD), have been found to have lower blood ghrelin levels, which may relate to gut dysfunction and faster disease progression. Preclinical studies in animal models show that ghrelin protects dopaminergic neurons, reduces inflammation, and improves motor and cognitive function, suggesting its potential as a therapeutic target in PD. However, ghrelin's short half-life and need for administration via intravenous or subcutaneous injections limits its potential as a therapeutic agent. Ginger, a safe and natural compound rich in gingerols, has been shown to raise ghrelin levels, reduce inflammation and protect neurons in experimental models. Together, these findings support testing ginger supplementation as a simple, non-invasive way to increase ghrelin levels and potentially slow disease progression in PD.

In this experimental medicine study, participants will attend up to four study visits at the John Van Geest Centre for Brain Repair, University of Cambridge with home visits provided if needed. At screening, informed consent, eligibility checks, and baseline measurements (including weight, height and medication review) will be completed, and participants will be asked to avoid all ginger-containing foods. They will receive materials for home gut function tests (whole gut transit time and methane breath test). At the baseline visit (within two weeks), participants will complete clinical and cognitive assessments (MDS-UPDRS, MoCA, semantic fluency, GIDS-PD), and blood samples will be taken before and one hour after the first ginger dose to assess the short-term ghrelin response. Participants will then take daily ginger supplements for 12 weeks.

At the end-of-intervention visit, all baseline assessments and blood sampling will be repeated. A final follow-up visit will take place four weeks after stopping the supplements to evaluate whether any effects on ghrelin levels, gut function, and inflammatory markers persist.

The ginger capsules used in this study (Lamberts) are FDA-recognized as safe (GRAS, 21CFR182.10). The supplement is well tolerated, with only rare mild gastrointestinal effects (e.g., heartburn, stomach discomfort) reported in previous studies. Participants will be asked to report any adverse events (AEs) or missed doses. Any serious adverse events (SAEs) will be reported to the Sponsor and Research Ethics Committee within 15 days if deemed related and unexpected.

Blood samples taken during study visits will be processed and stored for analysis of ghrelin levels, inflammatory markers and gut hormones. Data will be analyzed using appropriate statistical methods (e.g. repeated measures ANOVA), with a significance level of p\<0.05 and correction for multiple comparisons. All data will be pseudoanonymised and stored securely in compliance with GDPR and University of Cambridge policies.