Insulin — a hormone that helps regulate your blood sugar — appears to play a role in normal memory processes. Insulin irregularities may contribute to cognitive and brain changes associated with Alzheimer's disease.

In the past several years, researchers have been investigating the use of insulin to treat Alzheimer's disease. One of the challenges is how to provide insulin in such a way that it improves brain function without significantly disrupting your blood sugar levels. If your blood sugar drops too low, for example, it can create complications, such as confusion, heart palpitations, anxiety and visual disturbances.

Early research suggested that when taken as a nose spray, insulin could possibly improve memory and help preserve cognitive function in people with early Alzheimer's disease or mild cognitive impairment.

However, study results have been mixed. Some recent trials showed negative results. A large, well-designed study investigating the impact of nasal insulin on people with mild cognitive impairment or mild Alzheimer's disease found no benefits from the drug. But others found that nasal insulin may improve some aspects of memory and daily activity.

While optimism for insulin has been dampened, researchers are still trying to understand if and how insulin might be used to manage Alzheimer's disease and other dementias.