Ed Blonz On Nutrition
DEAR DR. BLONZ: I have a question about selenium supplements. I have been taking a product that contains 400 micrograms of selenium per tablet. The recommended dosage is two tablets per day. I have been taking this since July, but lately I have noticed that my hair has been falling out. I have since learned that 800 micrograms of selenium can be very toxic and cause hair loss. I have stopped taking the product, but would like to know how I can cleanse my system of this supplement and, just as important, how long it will take before my hair grows back. -- A.F.
DEAR A.F.: I am quite surprised that an over-the-counter supplement would instruct you to take 800 micrograms per day. Despite the fact that selenium is a wonderful nutrient, it also has a narrow margin of safety. Let me give you some numbers. The estimated safe and adequate intake is between 50 and 200 micrograms per day. That is the level that the average individual should aim for. Selenium has a Tolerable Upper Level Intake (UL) of 400 micrograms per day. The UL is the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects in almost all individuals. Jump from there to the Lowest Observed Adverse Effect Level (LOAEL) of selenium, which is 910 micrograms per day. The LOAEL is the level that should be considered unsafe for everyone. Also take into consideration the uncertainty factor, which means that some people are more tolerant or sensitive to selenium than others. (There are always exceptions, such as an individual following a regimen prescribed by a physician.)
The bottom line is that you are taking a potentially hazardous level of this nutrient. Prolonged intake above 900 micrograms per day is associated with toxicity symptoms -- one of which is hair loss. Other symptoms of a chronic selenium overdose include a garlicky odor to the breath, sweat and urine; a mottling of the teeth; abnormal nail growth; skin lesions; digestive problems; and nervous-system disorders. You also need to consider that the 800 micrograms of selenium you were taking was independent of any you were getting from your diet.
Selenium is present in foods, but the amount depends to a great degree on the selenium content of the soils and water in which they're grown. Selenium tends to be highest in soils west of the Mississippi River and east of the Rocky Mountains. Low selenium areas of the United States include the Northeast, Pacific Northwest and Southeastern coastal plains. One study found that feed corn from South Dakota, for example, contained 11 times the selenium as a similar corn grown in Michigan. (Its presence in feed corn is what makes meat a source of selenium.) Typical food sources of selenium include Brazil nuts; seafood such as tuna, clams, oysters, swordfish and lobster; meat; and grains such as corn, oats and wheat.
You were concerned about how long it would take for your hair to grow back. Unfortunately, there are no general rules, but research has shown that many chronic overdose symptoms can "correct" themselves over time. One of the metabolic effects of selenium overdose is that it interferes with an amino acid (cystine) used in the production of hair and nails. This is a logical explanation for why your hair fell out.
A diet high in protein might help, as it would provide a pool of amino acids to help "wash out" the selenium-contaminated amino acids from your body. Aside from that, it would be in your best interest to eat a high-fiber, plant-based diet and drink at least eight glasses of water a day. This would set up a process in which the greatest amount of healthful foods would be coming in and passing through your body -- a condition that makes sense when you're trying to assist eliminate an unwanted substance. I also encourage you to contact your health professional immediately and inform him or her of this situation to find out if there are different recommendations tailored to your specific situation. Good luck and please let me know how things work out.
Send questions to: "On Nutrition," Ed Blonz, c/o Newspaper Enterprise Association, 200 Madison Ave., New York, NY 10016.