evidence: - Low levels of certain nutrients. Not getting enough of certain vitamins or minerals in your diet can cause dementia symptoms. This includes not getting enough thiamin, also known as vitamin B-1, which is common in people with alcohol use disorder. It also includes not getting enough vitamin B-6, vitamin B-12, copper or vitamin E. Not drinking enough liquids, leading to dehydration, also can cause dementia symptoms. [...] - Low levels of certain vitamins and nutrients. Low levels of vitamin D, vitamin B-6, vitamin B-12 and folate can increase the risk of dementia. [...] Get enough vitamins. Some research suggests that people with low levels of vitamin D in their blood are more likely to develop Alzheimer's disease and other forms of dementia. You can increase your vitamin D levels with certain foods, supplements and sun exposure.