Selenium maintains a healthy brain. According to a new study published in "American Journal of Epidemiology.", Selenium intake throughout life may increase the efficiency of cognitive function as a person grows.   

"In this cross-sectional survey of cognitive function in rural elderly Chinese, we found that decreasing selenium levels as measured in nail sample are associated with lower cognitive scores when controlling for age, gender, education, body mass index and APOE status," said Indiana University researcher Sujuan Gao, the study's lead author.

The main natural sources of selenium are broccoli, Banana, Peas, Garlic, onions and rice. Selenium is also known to prevent prostate cancer and a immune booster. 

The researchers found that the difference in cognitive scores between those with the lowest selenium levels than those with the highest was tantamount to a 10-year age difference.  For selenium to be effective in brain function, long term intake is preferable. Consumer health advocate Mike Adams, who is the author of "The Seven laws of Nutrition" agreed with Mr. Gao’s statement that Selenium exposure, unlike other factors studied for Alzheimer's disease, is a factor that is easily modifiable by changing dietary habits or through supplements