Editor’s note: Wellness Word is an informational column which is not meant to replace a health care professional’s diagnosis, treatment or medication.
Should Selenium Supplementation Be Avoided?
By Hari Dass Khalsa, DC
Selenium is a trace mineral essential to good health but necessary only in small amounts. It is interesting to note that before it was found to be an essential nutrient, selenium was considered remarkably toxic to humans. Early research was optimistic that selenium supplementation might help prevent cancer and certain cardiovascular problems. A breakthrough occurred in 1973, when it was observed that selenium protected against oxidative damage in selenium-deficient rats. However, recent research has found that selenium supplementation might be more harmful than beneficial.
An international medical research team reported in Annals of Internal Medicine that selenium supplements are likely to increase the risk for diabetes. In this randomized, double-blind, placebo-controlled trial, 1,202 participants were given either oral selenium or placebo. During a follow-up of over 7 years, type 2 diabetes developed in 58 selenium recipients but in only 39 placebo recipients.
Another study examined the relationship between the use of multivitamins containing selenium and the risk of prostate cancer. The study investigated 295,344 men with a mean age of 62 years who were cancer-free at enrollment. The researchers discovered that persons taking high levels of multivitamins containing selenium have increased risks of advanced and fatal prostate cancers.
Yet another study investigated selenium for the prevention of cardiovascular disease. In this randomized, double-blind, placebo-controlled trial, over 1,000 subjects were given either oral selenium or placebo. This research team found no overall effect of selenium with any of the cardiovascular disease endpoints.
Selenium supplementation might be beneficial in certain populations, such as those with HIV or those with severe gastrointestinal problems, such as Crohn’s disease. Additionally, selenium supplementation may be beneficial in regions of the world where diets are low in selenium, such as China, but there is no evidence of selenium deficiency in the United States. Thus, selenium supplementation is a real public health concern. More than 1% of the U.S. population takes selenium supplements, and more than 35% takes multivitamin and multi-mineral supplements that often contain selenium.
In light of information that selenium may be associated with increased health risks, caution is recommended. Selenium supplementation should be viewed as having uncertain and possibly toxic effects. Overt symptoms of acute and chronic selenium toxicity include brittleness and loss of hair and nails, fatigue, neurologic damage, hepatic degeneration, gastrointestinal disturbances, enlarged spleen, and chronic dermatitis.
The amount of selenium in soil, which varies by region, determines the amount of selenium in the foods grown in that soil. Animals that eat grains or plants grown in selenium-rich soil have higher levels of selenium in their muscle. Plant foods like rice and wheat are the major dietary sources of selenium in most countries. In the United States, meats and breads are common sources of dietary selenium. Most Americans consume enough of these foods to get adequate amounts of selenium without the need for supplementation.
Dr. Hari Dass Khalsa is a chiropractor specializing in the non-surgical treatment of spinal conditions with offices located in the Hawthorne District. Please call 503.238.1032 for more information.