The Canadian province of Quebec is the largest producer and exporter of maple syrup in the world. More than two years ago, two students from Montreal toyed with the idea of exploring the health benefits of this popular condiment as part of their after-school research project. In search for a mentor, they approached Alex Parker, a professor at University of Montreal and a neuroscience researcher at University of Montreal Hospital Research Centre.
Catherine Aaron and Gabrielle Beaudry were already familiar with the works of Parker. As a backgrounder, Parker had demonstrated how sugar prevented the occurrence of amyotrophic lateral sclerosis or ALS using C. elegans worms as an animal model. Aaron and Beaudry took inspiration from this earlier finding. They wanted to test the effect of maple syrup—a sugary condiment—on neurodegenerative disease.
Parker and another researcher Martine Therrien supervised the research project of Aaron and Beaudry. The team added maple syrup to the diet of C. elegans worms. Take note that Parker genetically modified these nematodes to express the protein TDP-43 involved in ALS in motor neurons.
Results of the experiment revealed that maple syrup decreased several age-dependent phenotypes caused by the expression of TDP-43A315T in C. elegans motor neurons and requires the FOXO transcription factor DAF-16 to be effective.
“We just gave them a supplement of maple syrup at various concentrations and compared with a control group that had a normal diet,” said Aaron. “After twelve days, we counted under the microscope the worms that were moving and those that were paralysed. The worms that had consumed the highest dose of syrup were much less likely to be paralysed.”
“When they are adults, around 12 days, their motor neurons break down. Normally, at two weeks of life, 50 percent of the worms are completely paralysed,” said Parker. “But among those that received a diet enriched with 4 percent maple syrup, only 17 percent were paralysed. We can therefore conclude that maple syrup protects neurons and prevents the development of amyotrophic lateral sclerosis in C. elegans worms.”
One of the researchers, Therrien, explained that sugar could be good for the nervous system. Diseased neurons require more energy to combat toxic proteins and sugar provides this requirement.
However, apart from sugar, maple syrup is also rich in antioxidants called polyphenols. The researchers isolated phenols in the syrup to identify further the specific types of polyphenols. Upon isolation, they found out that maple syrup contains gallic acid and catechol. These polyphenols have a neuroprotective effect.
Pure maple syrup contains low concentrations of these polyphenols. Therrien surmised that the combination of sugar and polyphenols was responsible for preventing the occurrence of ALS in C. elegans.
Of course, it is also wroth mentioning that too much sugar can have a negative impact on health. Parker cautioned that the life expectancy of C. elegans is only three weeks. This short lifespan spares them from the long term-effects of sugar.
It is worth mentioning that previous studies reported that a diet high sugar results in alterations in the structure and functions of the brain. Other studies have also reported that dietary glucose shortened the lifespan of C. elegans by inhibiting the activities of FOXO family member DAF-16 and the heat shock factor HSF-1, thus concluding that a diet high in sugar promotes accelerated aging or the development of age-related diseases.
ALS or amyotrophic lateral sclerosis is a rare neuromuscular disease that causes paralysis and death a few years after the onset of symptoms. There is no available cure but studies during the past years have been advancing due to increasing public awareness and research funding fuelled by the ALS Ice Bucket Challenge awareness campaign in 2014.
Further details of the study are in the paper “Maple Syrup decreases TDP-43 Proteotoxicity in a C. elegans Model of ALS” published in April 2016 in the Journal of Agricultural and Food Chemistry.