Plant sterols seem to prevent the development of Alzheimer's, according to a recent study by researchers at the University of Saarland, who have demonstrated that a specific sterol – stigmasterol - inhibits the formation of proteins that are believed to play an important role in the development of the disease. The study was published in the Journal of Neuroscience.
"Plant sterols are found in some nuts, seeds and vegetable oils in various combinations,” said Marcus Grimm, head of the experimental neurology laboratory at the University of Saarland. “They lower cholesterol, and as such they are extensively used in the food industry and as a food supplement."
Elevated cholesterol levels have long been suspected of increasing the risk of developing Alzheimer's.
"Studies have already shown that cholesterol promotes the formation of so-called senile plaques," said Grimm. These plaques consist of proteins, mainly from the beta-amyloid proteins that accumulate in the brain and the nerve cells. They are considered one of the main causes of Alzheimer's.
The research team led by Grimm has now joined forces with scientists from Bonn, Finland and the Netherlands, to find out how the sterols that we take in through food influence the formation of these plaque proteins. It was found that one particular sterol – stigmasterol - inhibits protein formation.
"Stigmasterol acts on specific molecular processes, but it also reduces enzymatic activity, inhibiting the formation of Alzheimer's disease related proteins and altering the structure of the cell membrane," said Grimm. "Collectively, this leads to fewer beta-amyloid proteins."
In animal studies, the researchers were able to confirm this positive effect. Overall, the researchers were able to show in their study that different phytosterols affect various cellular mechanisms and therefore should be evaluated differently.
"Especially in relation to Alzheimer's, it seems to make sense to look at the action of individual phytosterols in the diet rather than a mixture of them," said Grimm.
