Vitamins are powerful antioxidants, but they play a crucial for the body in other respects too. According to recent studies vitamin B is essential for proper mental development as well as maintenance, and the deficiency of vitamin B complex can cause (or worsen) a host of problems including dementia, poor memory, depression, insomnia, mental deterioration and other nervous disorders. Some researchers even show a definite association between the development of neurological symptoms and vitamin B deficiency in the elderly.