The findings of a randomised, blinded clinical trial of the sweetener mannitol have been published. The results indicate that the molecule is safe and tolerable, but the study has not replicated the benefits that had previously been reported.
In 2013, researchers from Tel Aviv University in Israel published preclinical data evaluating mannitol in four models of Parkinson’s. Mannitol is a low calorie sweetener that is sometimes used to lower increased pressure around the brain. Remarkably, the researchers in Tel Aviv found that mannitol exhibited impressive neuroprotective properties in their models of Parkinson’s. These encouraging results compelled members of the Parkinson’s community in Israel to set up a crowd funded platform to share their experiences of self-administering mannitol. The platform, Clinicrowd, quickly gained a world-wide following, and is still a community for patients and those at-risk to share experiences, treatments, and insights.
Over time, the Clinicrowd platform collected a lot of data from individuals taking mannitol and this dataset of anecdotal reports provided strong justification for initiating a proper clinical trial. Researchers at the Hebrew University of Jerusalem set up a phase 2a, randomised, double-blind, placebo-controlled, dose-escalating study in 2019. They recruited 22 individuals with Parkinson’s who were treated with mannitol or a control treatment for 36 weeks.
At the end of the study, the results found that daily treatment of mannitol (up to 18 grams per day) was safe. Six of the 14 participants in the mannitol group reported significant abdominal discomfort, but the treatment was otherwise well tolerated. While the study was not large enough to determine efficacy, the researchers did not see any change in the progression of the Parkinson’s symptoms over the 36 week study; nor did they witness any restoration of participants’ sense of smell, which had been previously reported in the Clinicrowd testimonies.
The results of the study have been published but the authors have not indicated any plan to conduct a larger and longer study to determine if mannitol may indeed have any disease-modifying effects. Perhaps we will learn more later this year.
