Alzheimer’s is surely among the best known & most studied ailments that affect the human brain. Actively exercising your brain & body appears to be the best active defence against contracting the condition. Inheriting good genes, is the best passive defence.
There is no 100% effective treatment for Alzheimer’s but there are drugs that appear to have some benefit. One of the most unusual, from a chemical structure standpoint, is Memantine. The name of the drug has roots in the word diamond & a link to the X-Men of comic book fame.