Dietary intake of phytosterol blends, mainly containing stigmasterol, could be beneficial in preventing Alzheimer's disease, according to new research in mice.
The study, published in The Journal of Neuroscience, examined how the sterols that we ingest influence the formation of senile plaques which are associated with the development of Alzheimer's disease (AD).
Senile plaques are composed of proteins, particularly beta-amyloid proteins, and deposit at nerve cells within the brain. They are regarded as one of the main causes of AD.
Led by Marcus Grimm of Saarland University, Germany, the research team noted that high cholesterol levels have been long suggested to increase the risk of developing Alzheimer's disease, with studies suggesting cholesterol promotes the formation of senile plaques.
"As plant sterols are the equivalents of animal cholesterol, they can in principal influence metabolic processes, where cholesterol is involved," explained Grimm.
"Because they also lower cholesterol levels, they are extensively used in the food industry and as dietary supplements."
Grimm and his colleagues examined how the sterols that we ingest influence the formation of these plaque proteins - finding that one sterol in particular, stigmasterol, actually inhibited protein formation.
"Stigmasterol has an effect on a variety of molecular processes: it lowers enzyme activity, it inhibits the formation of proteins implicated in the development of Alzheimer's disease, and it alters the structure of the cell membrane," Grimm revealed.
"Together, these effects synergistically reduce the production of beta-amyloid proteins."
The team then fed mice with stigmasterol-enriched diets - which confirmed these protective effects in vivo and suggesting that dietary intake of phytosterol blends mainly containing stigmasterol might be beneficial in preventing AD.
"Particularly in the case of Alzheimer's disease, it seems expedient to focus on the dietary intake of specific plant sterols rather than a mixture of sterols," Grimm added.