1. You’ve Got the Blues
Vitamin D improves levels of the neurotransmitter serotonin, which in turn could lift your spirits. In a small 1998 study, healthy people given vitamin D supplements during the winter reported greater positive feelings than people given no D. However, a larger study in women over 70 found no significant mental health benefit.
A 2014 study published in the journal Neurology found that moderate-to-severe vitamin D deficiency in older adults may double the risk for some forms of dementia, including Alzheimer’s disease. Dementia is a decline in thinking, behavior, and memory that negatively affects daily life. Alzheimer’s disease is the most common form of dementia, accounting for as many as 80 percent of dementia cases, according to the Alzheimer’s Association.