Selenium Supplement Summary

SEATTLE - Are you getting enough selenium in your diet? Selenium is a mineral. It’s also a powerful antioxidant. It’s one of the hot nutritional supplements right now because it may have a role in preventing some forms of cancer - especially prostate cancer.

According to the UC Berkeley Wellness Letter, there’s also some preliminary evidence selenium may protect you against heart attacks, colon polyps, asthma, even rheumatoid arthritis.

Which leads to the question, should you take a selenium supplement? Health experts say probably not. That’s because test results have been inconsistent. Some tests show selenium protects against certain cancers, while other tests found no benefit at all. We just don’t have solid data yet.

According to the National Institutes of Health, while selenium is being used to prevent certain types of cancer, “there is not enough information to show that this is effective.”

The UC Berkeley Wellness Letter says “it’s too early to recommend selenium supplements for everyone. Selenium is promising, but it’s no miracle mineral.”

The fact is, selenium deficiency in this country is rare, and according to the Wellness Letter's Dr. John Swartzberg, you should be able to get all the selenium you need from your food, especially if you eat whole grains, fish and nuts.

"You don't need much, only 55 micrograms,” Dr. Swartzberg says. “A microgram is one millionth of a gram, so you need just a teeny bit to give you an adequate amount." Brazil nuts are loaded with selenium; a half ounce (that’s just 3 or 4 nuts) has 272 micrograms.

Other good sources of selenium include:

• Canned light tuna (3 ounces) 68 micrograms
• Sole (3 ounces) 50 micrograms
• Sardines (3 ounces) 45 micrograms
• Halibut (3 ounces) 40 micrograms
• Whole-wheat spaghetti (cup) 36 micrograms
• Sockeye Salmon (3 ounces) 32 micrograms

The Wellness letter says “if you take a multivitamin, make sure it contains selenium” and you should be covered.

A heads up for anyone who takes a selenium supplement: The Wellness Letter says the difference between “an optimal and toxic dose is small.” The safe upper limit for adults is about 400 micrograms a day. Go past 1,000 micrograms and that can cause a number of problems, including nausea, vomiting, and hair loss.

The National Institutes of Health is conducting a large trial to see if selenium or Vitamin E can reduce the risk of prostate cancer. Result from this SELECT study won't be known for about seven more years.

For more information:

Mayo Clinic: Selenium Supplements

National Institutes of Health: Selenium Fact Sheet