There is some impressive research indicating that selenium is beneficial for preventing and supporting treatment of prostate cancer. In fact the fully enrolled SELECT trial is now in progress, with over 30,000 men who did not have prostate cancer at the time of enrollment. The trial will test whether 200 mcg daily of selenium, 400 IU of vitamin E, or a combination of selenium and vitamin E prevents more prostate cancer than a placebo. We won't get the first interim result until five years after enrollment was completed, which probably means that the first interim result is still several years away. There's also a similar European trial now underway.
I've been taking at least 200 mcg of selenium daily as a supplement since shortly after I was diagnosed with prostate cancer eight years ago. I use the supplement, because I live in an area where selenium is deficient in the soil and it is fairly hard to get an adequate amount of selenium from food unless you get it in garlic grown in selenium rich soil or in certain wheat, or from Brazil nuts. (Northern Nebraska and the Dakotas, in contrast, have an abundance of selenium in the soil, but many of the heavily populated areas in the US are deficient.)
I knew that Brazil nuts were the best source of selenium, but they are hard to crack. So I was glad this December when I found a brand of shelled Brazil nuts, but my store does not stock them past Christmas. I figured there must be a fairly easy way to get the nuts out of that tough shell. A week ago I actually read what was stated on a package of the nuts, and learned a trick. If you freeze the nuts for 24 hours, a nutcracker will open them fairly neatly with little effort.
I also now know that a few nuts go a long way. I wanted to check how much selenium I was getting in the average shelled nut and went to this National Institutes of Health Government website: [url]http://dietary-supplements.info.nih.gov/factsheets/selenium.asp[/url] . I learned that just one ounce of the nuts provides a whopping 544 micrograms of selenium, more than double the dose I was aiming for.
I just weighed some Brazil nuts, adding the shelled nuts to a scale til I reached an ounce. It took just five nuts, so each is about 110 mcg, and just two would give me about the dose I am looking for.
The US Institute of Medicine has established 400 mcg as a maximum safe dose. However, toxicity from an excessive dose gives plenty of warning, such as "gastrointestinal upsets, hair loss, white blotchy nails, garlic breath odor, fatigue, irritability, and mild nerve damage," quoting from the Government fact sheet. Nails, breath, and hair loss are the warning symptoms I have heard mentioned most frequently. (That said, the TV show CSI had one case that turned out to be selenium poisoning, but the dose was extremely high.) The fact sheet also gives information about selenium deficiency.
Recently one study was published that found a possible weak association between selenium and Type II diabetes, the kind where the body produces enough insulin but isn't able to get it where it needs to go.
Several other studies have found no such association. However, Dr. Charles Myers, who specializes in prostate cancer and is one of the leading experts in nutrition and prostate cancer, recommends not exceeding 200 mcg to be on the safe side. While the association found in the one study was not strong, Dr. Myers noted "... in this study, serum [blood] selenium levels were measured and there was a pretty tight link between increasing selenium levels and increased risk of diabetes, which makes the likelihood of a link greater."
Personally, I don't want to give up selenium because I'm very impressed with the stunning 64% reduction in incidence of prostate cancer achieved in the "Clark" trial that caught everyone's attention back in 1996.
This huge reduction has also stood up as patients were observed for additional years of followup.
I want a piece of that action for myself as its likely selenium also influences prostate cancer that already exists. (What's more, certain families have a deficiency of an enzyme named superoxide dismutase and are at rincreased risk of prostate cancer. Dr. Myers has stated, based on research he has reviewed: "If these people take selenium and other antioxidants, their risk of developing prostate cancer is reduced by 80%." Wow!
Because of the recently discovered safety issue, Dr. Myers recommends that those of us on selenium have our fasting blood sugar tested, and if it is above 90, he recommends discussing a possible insulin resistance problem with our doctors. For patients with known diabetes or insulin resistance, he suggests getting the selenium blood level tested and perhaps stopping selenium until research clears up the issue.
Because of my challenging case, I have been on a higher dose of selenium, at my own choosing but following the lead of a doctor (not Dr. Myers), 400 mcg vice the recommended 200 mcg, for more time than not. After the recent selenium study was published I cut back the dose to 200 mcg. I am clearly not diabetic, but my latest fasting blood sugar this spring was 90, so I am going to keep an eye on this. I also consume a lot of green tea and lycopene which are known to combat insulin resistance.
Is anyone else eating Brazil nuts to get enough selenium, and if so, did you know about the freezing trick? Had you heard about the possible safety issue?