Last Modified on May 10, 2015
Selenium has had a lot of publicity in recent years as a cure or preventative for cancer. It is also believed to be a healthful supplement to take for a number of health problems. A mineral found in the soil, selenium is one of the essential elements that we must have, even though only a tiny amount is needed. There have been many studies done on the relationship between selenium and cancer, diabetes, thyroid problems, cognitive function and many other ailments.
What is Selenium?
Selenium is a nonmetallic trace element rarely found in its pure state in nature; it is produced as a mining by-product of sulfite ores, such as copper. It has certain industrial uses, but for us, selenium is important because it’s essential for good health.
Selenium and Glutathione
Probably the important reason for ensuring that we have enough selenium is that our bodies need it for the production of glutathione peroxidase (GSH-Px), an antioxidant that aids every cell in our bodies to fight illness and maintain health.
When you’re sick, you need more glutathione; the body uses more than it normally would. When glutathione levels have been depleted, free radicals accumulate and damage cell membranes. Glutathione removes toxins from the body (think of it like fly paper), so the harder it has to work, the less glutathione remains. Glutathione levels are constantly being depleted and need to be renewed.
Maintaining Glutathione Levels
Selenium is important in order for the body to produce glutathione. Studies have shown low levels of both selenium and glutathione when people are ill. It would seem logical to think that taking up to 200 mcg/day selenium when sick would be a good idea, but we could not find research to confirm this.
If you took selenium when you were sick, please let us know the details on how it worked for you.
Diet. When they’re well, people usually get all the selenium that is needed from their food. However, when you’re sick, do you eat a balanced diet? People tend not to.
Exercise is also a good way to help restore glutathione levels, but sick people don’t normally exercise.
Bioactive whey protein, made from denatured proteins and produced from raw milk that does not contain hormones, pesticides or antibiotics will help to maintain glutathione levels.
Obtaining Selenium from a Healthy Diet
Plants draw selenium from the soil, but the amount of selenium in the soil varies. In most parts of the world, there is sufficient selenium in the soil. However, in one region of China, people suffered from multiple ailments, eventually traced to selenium deficiency in the soil, and they were subsequently given selenium supplements.
- Selenium can be obtained from a wide variety of foods. However, selenium from grain-based foods is dependent upon how much selenium was in the soil. Most vegetables and fruits do not contain much selenium.
- Tuna is very high in selenium (4 oz. = 123 mcg), but it is also found in other seafood, including shrimp, sardines, oysters and salmon.
- Brazil Nuts contain 544 mcg per ounce; selenium is also found in black walnuts, cashews and macadamia nuts.
- Whole-wheat bread has 11 mcg per slice. It is also found in other whole-wheat products, such as English muffins, pita bread, etc.
- Meat contains selenium. On average, a 3 oz. serving of lean meat or poultry will supply 25-35 mcg of selenium.
- Sunflower seeds supply 78 mcg of selenium per 100 grams of seeds.
Benefits of Selenium:
- A sufficient supply of selenium is essential for the production of the critical antioxidant enzyme glutathione. This may be the most important benefit of selenium. It appears that benefits claimed for selenium could be the result of selenium providing for adequate levels of glutathione. This seems to be a moot point, however – if it works, it works.
- Helps to support the immune system.
- Needed to regulate thyroid function.
- Assists in preventing cataracts.
- Low levels of selenium are linked to HIV, Crohn’s Disease, kidney dialysis and intravenous feeding.
- Antioxidant properties may help to prevent damage to cells from free radicals and the prevention of heart disease.
- May help to reduce the risk of developing prostate, skin and some other cancers. See SELECT trial information below.
- Inflammation associated with rheumatoid arthritis may be lessened.
- Selenium is said to reduce the risk of sunburn.
The FDA and Selenium
In 2003, the FDA issued a qualified approval for selenium as a cancer preventative, as long as supplement claims stated that while some evidence exists that selenium may reduce the risks of some cancers or has some carcinogenic effect, this evidence is limited and not conclusive.
At the end of a rather long opinion, the bottom line is that selenium supplements can be sold, but the FDA won’t allow the manufacturers to say that the supplements will be useful in preventing cancer.
Selenium and Cancer
A few years ago, there was a lot of excitement about the possibility of selenium preventing cancer. Many studies tried to determine whether selenium could help to prevent cancer, either taken alone or with vitamin E. Research results tended to be inconclusive and can seem contradictory.
The SELECT Trial for Prostate Cancer
The Selenium and Vitamin E Cancer Prevention Trial (SELECT) divided 35,000 men, considered to be at moderate risk of prostate cancer, into 4 groups in the U.S., Canada and Puerto Rico. This study began in 2001. Their conclusions were as follows:
Group 1: Received only synthetic Vitamin E (400 IU/360 mg/day)
Conclusion: The synthetic Vitamin E was stopped in 2008. A follow-up in 2011 revealed that more men developed prostate cancer than in the placebo group. Never take synthetic Vitamin E.
Group 2: Received only selenium (200 mcg/day as L-selenomethionine)
Conclusion: This did not work as expected. The researchers speculated that the problem was the form of selenium given to the men. They received selenomethionine, which had a synthetic component. The researchers felt that selenium yeast, used in previous trials at a dosage of 200 mcg/day, would have been a better choice, but only for men who began the trial at a low selenium level.
Group 3: Received both Vitamin E and selenium
Conclusion: Again, the researchers felt that the form and dosage had been wrong. Selenium yeast had previously been shown to have a protective effect in past trials. They felt that the type and dosage were wrong for the vitamin E. Natural vitamin E at a dosage of 50 IU (compared to the 400 IU used in SELECT) was proven beneficial in other trials.
Group 4: Received only a placebo
FORM AND DOSE MATTER, A LOT!
IMPORTANT: Before starting to take selenium, it’s important to know your selenium level. Selenium had a protective effect for men who had a low selenium level. However, men who started taking selenium when they already had a high level of selenium had an increased risk of developing aggressive prostate cancer.
A blood test for selenium without insurance at a walk-in lab costs about $150.00.
The SELECT trials were studying prostate cancer. Whether taking natural Vitamin E and selenium yeast at the recommended doses would be helpful against other cancers is unknown. It would be a case of, “Proceed at your own risk.”
Selenium and Alzheimer’s
Research has been inconclusive as to whether selenium supplements could prevent Alzheimer’s. A French study of over 4,000 people aged 45-60 found that those who took a supplement for 8 years containing 100 mcg selenium, ascorbic acid, vitamin E, beta-carotene and zinc had improved memory and speech compared to those taking a placebo. However, they could not say whether or not selenium by itself would have the same effect.
Selenium and Diabetes
Some studies show a possible link between as little as 200 mcg selenium and an increased risk of Type 2 Diabetes.
Recommended Selenium Doses
- Children: 20 – 40 mcg (micrograms)/day
- Adults: 55 mcg/day
- Pregnant women: 60 mcg/day
- Breastfeeding women: 70 mcg/day
How Much Selenium is Too Much?
According to the U.S. Institute of Medicine, over 400 mcg of selenium a day is considered an overdose. Over 800 mcg would be a toxic level, leading to selenosis. This can result in hair loss, gastrointestinal upset, garlicky breath, discolored nails, irritability, fatigue and possibly mild nerve damage.
It needs to be pointed out that selenium can be ingested during the day from multiple sources, including food, selenium supplements and multivitamins or other supplements containing selenium. Taking 2 – 200 mcg capsules would result in a daily dose of over 400 mcg for most people.
Selenium is essential, especially to maintain necessary glutathione levels, but adequate amounts can normally be received from food. If taking a supplement, be careful as to the form of selenium taken and the dosage.
Please let us know if you take selenium and how it is working for you.
Hi, Well, I recently had a urine test and blood work done. I posted a day ago that my urine test came back with very high selenium amount; over 100mcg normal value. Well, my blood work just came in and a few things are off. Maybe someone can guide me a little as I am concerned but my doc didn't seem so. The T4 and T3 were normal but I put the values incase they mean something inregards to the TSH reflex. Thanks!
TSH w/ Reflex to FT4 was 0.39 (0.40-4.50 is normal)
T4, Free was 1. 4 (0.8-1.8 is normal)
T3 uptake was 35 (22-35% is normal)
Alkaline Phosphate was 38 (Low) (40-115 is normal)
Albumin/Globulin ratio was 2. 2 (high) (1.0 - 2.1 is normal)
San Fernando, Philippines
1144 PostsPosted by Anthony (Philadelphia, Pa) on 05/31/2012
Well I had a 24 hr urine test done for heavy metals and in this included selenium. Well everything came back normal except my selenium The normal range is 150-250 and I was 355. My doctor was shocked and could not find I reason as to why.
I do take selenium supplements but I just started them several days before, besides that there is not much else of selenium in my diet.
I read there could be a connection between high selenium and diabetes but I have a well controlled diet and my fasting glucose was 86 and A1C was well within the normal range.
The other thing I read was that Selenium and thyroid work together... Something along those lines. I just couldn't understand if I would be hypothyroid or hyper in relation to selenium being high.
Any info would be helpful, thanks!Louisville, Ky, Usa