Dr. Bruce Ames is one of my heroes. For many decades, he has been the head of the Department of Biochemistry and Molecular Biology at UC Berkeley.  It’s unlikely that any single individual has produced more published research in the field of nutrition than Dr. Ames.  And, he is still at the top of his profession at the age of 83.

His latest research was published in the June issue of the Journal of American Experimental Biology. It concerns the subtle effects of selenium deficiency.  Selenium is very subject to deficiency because many soils in the world are lacking in it, and plants can grow perfectly well without it.  You’ve heard about goiter belts resulting from iodine-depleted soils, and a similar situation exists with selenium.

What Dr. Ames discovered is that even modest, sub-clinical selenium deficiency retards the activity of at least 12 important seleno-proteins.  These seleno-proteins have protective effects which are directly related to the prevention of age-related diseases, including heart disease, cancer, diabetes, and immunological condtions.

"The same set of age-related diseases and conditions, including cancer, heart disease, and immune dysfunction, are prospectively associated with modest selenium deficiency and also with widespread dysfunction of nonessential selenoproteins, suggesting that selenium deficiency could be a causal factor in many of the most common diseases of aging.  Modest selenium deficiency is common in many parts of the world; optimal intake of selenium could significantly prevent future disease."

So far, selenium has been associated with preventing breast cancer, prostate cancer, colon cancer, and skin cancer. More research is underway as we speak, and I look forward to great progress in disease control through selenium nutriture in the years ahead.

I will finish by taking a look at brazil nuts. Many people, the world over, eat brazil nuts to obtain selenium, and I am one of them because I love  the taste of them.   Brazil nuts are the highest selenium food on this planet, and by far. Theoretically, you could incur selenium toxicity from eating too many brazil nuts I say “theoretically” because I have never heard of any documented, clinical case of selenium poisoning from eating brazil nuts, and I have searched for it.  I got to thinking about it because of an episode of HOUSE in which the patient exhibiting bizarre symptoms turned out to have selenium toxicity from eating brazil nuts.  But, that was fiction, and I wanted to know if there were any comparable real-life cases.  I have searched the comprehensive medical database PubMed, and I have found nothing. If anyone knows of a documented clinical case of selenium poisoining from brazil nuts, please send me the information at This email address is being protected from spambots. You need JavaScript enabled to view it. .  It's complicated because according to Cornel University food researcher Dr. Donald J. Lisk, unshelled brazil nuts contain 100 micrograms of selenium per nut (which could add up quickly if you started chowing down) while the more commonly available shelled brazil nuts have only 12 to 25 micrograms per nut (which is still a lot  as foods go but with a wider margin of safety). I presume the difference relates to the locations from which the nuts are harvested. The US government says that the upper safe limit for selenium is 400 mcgs daily, although Dr. Lisk thinks it's quite a bit higher than that. And that may be why people have been known to eat a half-pound of brazil nuts at a sitting without incident. I don't do that, and I'm not recommending it. But, I will eat 3 or 4 brazil nuts at a sitting, and I do so often and without worry.