Most common: Alzheimer’s disease.

 A form of dementia, Alzheimer’s disease causes brain cells to deteriorate, but more specifically because there is an accumulation of protein both inside and outside of the brain cells that attacks the nerves, cells and neurotransmitters (chemicals in the brain).

Some alternative medicine options for Alzheimer's disease and other forms of dementia that have been studied include:

Vitamin E. Some studies have shown that vitamin E may slow the progression of Alzheimer's disease. Doctors warn against taking large doses of vitamin E because it may have a higher risk of mortality, especially in people with heart disease.

Omega-3 fatty acids. Omega-3s, a type of polyunsaturated fatty acid found in fish and nuts, may reduce the risk of heart disease, stroke and mild cognitive impairment.

However, in studies, omega-3 fatty acids haven't significantly slowed cognitive decline in mild to moderate Alzheimer's disease. More research is needed to understand whether omega-3 fatty acids benefit people with Alzheimer's and other types of dementia.

Coenzyme Q10. This antioxidant occurs naturally in your body. It's also necessary for normal cell reactions.

A synthetic version of this compound, called idebenone, showed some positive results in testing for Alzheimer's disease.

More studies are needed to determine safe dosages and potential benefits of coenzyme Q10.

Ginkgo. Extracts from the leaves of the Ginkgo biloba tree have antioxidant and anti-inflammatory properties that may protect cells in your brain from breaking down.

Some studies have shown that ginkgo may slow the progression of memory problems in people with Alzheimer's or other types of dementia. Other studies have found that ginkgo doesn't slow or delay the onset of dementia.