Mineral Spirits

Selenium has shown mpressive cancer-prevention prowess in rats and
other critters.

But the formerly obscure mineral may also be crucial for proper
brain function. Although researchers haven't yet figured out its exact
role, it appears selenium helps us maintain a happy, healthy mood.

A clue comes from a study in which 12 men, holed up in a research
facility for four months, were fed either a high- or low-selenium diet.
Those on the reduced-selenium regimen--and whose initial selenium levels
were low--were more prone to depression and hostility, report biochemist
Wayne Chris Hawkes, Ph.D., and clinical psychologist Linda Hornbostel,
Ph.D., in Biological Psychiatry (Vol. 39, No. 1).

Though the findings fit together nicely with a British study in
which selenium supplements boosted subjects' mood, it's unlikely that
selenium deficiency is responsible for much depression in the U.S., says
Hawkes, a researcher at the USDA Agricultural Research Service. How much
of the mineral you get depends less on what you eat than where that food
comes from. If your fruits, veggies, and livestock are raised in
selenium-poor soil, you may be at risk for deficiency. But selenium
levels are adequate in most U.S. farmland.

Not so, however, in New Zealand and parts of China, according to
Hawkes. (In the USDA study, in fact, the low-selenium group was fed New
Zealand beef.) In such countries, dietary selenium levels could be
insufficient for optimal mood maintenance.

Selenium's importance is underscored by the fact that when the
body's stock is being depleted, the brain is the last organ to give up
its supply But scientists still have little idea what the brain is doing
with its stash, or why low levels would alter mood.