Q. You have saved my sanity! I’ve always enjoyed your column, but never needed your advice until last year.
I had been suffering in silence as my hair changed its texture from wavy to straight. Then my fingernails began to deteriorate. I thought it was another consequence of growing older, until I read in your column that too much selenium in the diet could affect hair and nails adversely.
At the time I was taking a supplement that contained selenium along with the lecithin I wanted. I immediately switched to a lecithin-only supplement. After about six months, the nails began to recover. In another four to six months, my hair had become wavy again, and my nails were much stronger. Thank you!
A. Problems with hair and nails are often difficult to diagnose, so we are glad we gave you the clues you needed. Selenium is an essential mineral, but excess selenium can be toxic. Loss of hair and nails has occurred both among Chinese people whose diets were naturally high in selenium and in Americans taking supplements with too much selenium.
The tolerable upper limit of selenium is around 400 micrograms daily. Brazil nuts are high in selenium and an ounce (roughly half a dozen) provides 800 micrograms. Overindulging regularly could lead to selenium toxicity.