Day 120: use


Selenium is another powerful and unique trace mineral. It’s a metal that’s found naturally in water, soil and foods. Selenium affects our overall health even though it’s a mineral that we need in small amounts.


The Soil

Soil is absolutely important when growing foods because this is where they get their nutrients. Soil that’s lacking in nutrients like selenium will produce foods that lack nutrients too. Therefore, it’s important to be aware of the levels of nutrients like selenium in the soil that you get your foods from. Depending on where you live, getting locally grown foods may or may not benefit you depending on what the nutrients levels are in the soil. It’s important to note that processing foods will cause it to lose selenium. Click here to see a USGS (United States Geological Survey) catalog that shows what selenium levels are like in your county.

Leonardo Da Vinci Vitruvian man

The Body

Selenium is a metal that actually helps manage the levels of other heavy metals in your body as well as protect you against certain toxins in the environment and some toxins made by fungi.

Selenium is also a great anti aging mineral. Having selenium deficiency is rare in the U.S but is slightly more common in elderly individuals or those who are not healthy. One study showed that even small deficiencies can result in an increased risk of age related diseases like cancer, dementia, and heart disease. It does this by helping your body produce important antioxidants, and, function as one itself.

Selenium is a powerful antioxidant and cancer fighter. It may help prevent the formation of new blood vessels for cancer cells (angiogenesis), may help trigger cancer cells to kill themselves (apoptosis) or help keep cancer cells from spreading. Besides reducing the amount of free radicals like other antioxidants do, selenium’s unique quality is that it helps restore and recycle vitamin E, which is one of the most powerful antioxidants out there. Selenium is also essential to the formation of glutathione, which is another very powerful antioxidant that our body makes.


How Much Selenium?

Age Male Female Pregnant Lactating Upper Limits
1 – 3 Years 20 mcg 20 mcg 90 mcg
4 – 8 Years 30 mcg 30 mcg 150 mcg
9 – 13 Years 40 mcg 40 mcg 280 mcg
14 – 18 Years 55 mcg 55 mcg 60 mcg 70 mcg 400 mcg
18+ Years 55 mcg 55 mcg 60 mcg 70 mcg 400 mcg



Some of the best sources of selenium are meats. Specifically, the kidneys. Lamb and pork kidneys, as well as beef, are all great sources of selenium. Seafoods are also great sources of selenium as well. However, there is one class of foods that goes above and beyond the amounts of selenium found in meats. And, you don’t need to eat much at all.


Brazil Nuts

Brazil Nuts

1 Brazil nut can have around 95 mcg of selenium, which is up to 130% of the daily value for an adult. It’s also a good source of minerals like copper, magnesium and phosphorus.


snacktime2007 / Flickr
Mixed Nuts

This assortment of nuts (minus the metal ones) are packed with selenium. 1 ounce of mixed nuts has more than enough selenium than you need for the day. It contains over 110 mcg of selenium, which is over 160% of the daily value for adults. Interestingly enough, mixed nuts without peanuts contain far more selenium than mixed nuts with peanuts. With peanuts, 1 ounce of mixed nuts contains only 30-40 mcg of selenium, which is roughly 50% of the daily value for adults. If you are concerned about your selenium levels or have low selenium levels, you may want to try some mixed nuts without peanuts.


avlxyz / Flickr
Pork kidney

1 ounce or about 1/10th of a kidney has around 50 mcg of selenium. An entire pig kidney, which is about 230 grams, is absolutely bursting with selenium. A pig kidney has over 440 mcg of selenium, which is 600% of the daily value for an adult. This is above the recommended upper limits for people younger than 18 years of age and in some cases well over the upper limit. Kids and teenagers should avoid eating larger amounts of pork kidney. Stick to 1 ounce servings.


julesjulesjules m / Flickr

These mollusks are also a good source of selenium. Oysters contain 35-40 mcg in 1 medium sized oyster (about 25 grams). Farmed or wild oysters contain about the same amounts of selenium per oyster.


For those who have nut allergies, seafood allergies, or who just don’t plain eat meats or seafoods, there are also other foods from the soil that are high in selenium.

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Wheat (enriched Semolina or wheat durum)

This grain is packed with selenium. 1 cup of enriched semolina or wheat durum flour contains about 25 mcg of selenium, which is around 35% of the daily value for an adult. Wheat germ and wheat bran also contain similar amounts of selenium.




2 ounces of dry spaghetti (about 57 grams) contains about 40 mcg of selenium, which is almost 60% of the daily value for an adult.


Novalis / wikipedia
Mustard seeds

A surprising source of selenium, it contains 10-15 mcg of selenium per tablespoon. This is about 15-20% of the daily value for an adult.


hitthatswitch / Flickr

As a supplement, selenium has been showing much promise in the fight against cancer. One study by the Nutritional Prevention of Cancer (NPC) suggested that regular supplementation of selenium reduced the risk of prostate cancer in men that had normal PSA levels but low levels of selenium in their blood. The downside to this study was that selenium supplementation actually increased the risk of squamous skin cell carcinoma. It did not have an effect on other cancers like lung cancer, colon cancer and basal carcinoma skin cancer. It’s important to note that this is only 1 study. It does not guarantee or indicate that those who take selenium supplements will get skin cancer or even reduce their risk of prostate cancer. Talk to your doctor before considering selenium supplements for fighting off cancer.

Adults should go for doses no higher than 200 mcg daily. Higher doses and long term use of selenium supplements may help promote the formation of the superoxide anion, which is an extremely reactive form of oxygen.



  3. USGS Geological Survey of Selenium in the U.S. located at

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