Being Patient:In a new mice study, researchers showed that beta-amyloid — the toxic protein linked to Alzheimer’s — can gum up the olfactory system and could be a reason for the partial loss of smell that people with Alzheimer’s tend to experience. In a new mice study, researchers showed that beta-amyloid — the toxic protein linked to Alzheimer’s — can gum up the olfactory system and could be a reason for the partial loss of smell that people with Alzheimer’s tend to experience.