"A large multicenter team reports that Porphyromonas gingivalis, which is the key pathogen in gingivitis (gum disease) may be the actual causative agent in Alzheimer’s, which is a bold claim indeed. But they have several lines of evidence to back it up, and it’s a hypothesis that has to be taken seriously."

Since it is claimed that Indian people have a lower occurrence of Alzheimer, possible due to the consumption of turmeric, I looked up a link between gum disease and tumeric and found this: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3498709/