As with many hyped supplements, selenium has legitimately intriguing attributes, but is far from perfect.

One of my favorite resources, The Berkeley Wellness Letter, takes a critical look at the mineral in its December newsletter. Citing several recent studies, Berkeley concludes that selenium has been linked to cancer prevention because it may:

• stop DNA damage by being part of antioxidant enzymes
• boost immune function
• inhibit growth of blood vessels that tumors need to survive
• induce cancer cells to self-destruct

But this does not mean that you should run out and purchase a case of selenium. Berkeley has also found that research results are inconclusive — most notably that the optimal dose is unknown and that there is also a chance that too much selenium can be toxic.

For now diet may be the best method of ingesting selenium. The Wellness Letter includes a list of selenium rich foods. For a second opinion, check out the NIH's selenium suggestions.

Brazil nuts are number one on both lists.