All about the Essential Mineral Selenium

Overview

Selenium (abbreviated as Se) is an essential mineral that our bodies cannot produce independently. It’s a trace element that is generally found in the geological environment -- specifically, formations within soil on the Earth’s surface. 

In the human body, many proteins need Selenium to produce specific reactions.  As a trace element and a micronutrient, Selenium in the proper amounts supports the functions of the cardiovascular, endocrine, and immune systems. It has the potential to play a big role in metabolism, mood, sleep, sexual function, and possibly heart health, as well as to protect the body through its natural defense system. 

Selenium (Se) In soil

It’s important to understand the relationship between environmental exposure to Selenium and overall health. Soil that is low in Selenium can cause Selenium deficiency in the food chain. 

Ready availability of Selenium in the soil is not the only factor, however. The type of Selenium in the soil must be produced in a bioavailable form in order for plants and animals to absorb it. So, some research suggests water-soluble Selenium in soil may better indicate bioavailability than simply Selenium itself. Further, presence of Selenium in vegetation can provide a better estimate of bioavailability than the presence of Selenium in soil alone. 

Where do seleniferous areas exist? Reports have indicated that some regions rich in Selenium can be found in Ireland, Israel, Australia, Russia, Venezuela, China, the United States, India and South Africa. However, in China, the concentration of Selenium in soil is more generally known to be the lowest in the world.

It should be noted that Selenium is a non-renewable resource. As a whole, the world's Selenium resources are rare, and scientists say they need to be managed carefully. 

Selenium deficiency in the body

The most common symptoms are fatigue and brain fog. Selenium levels may influence instances of cancer, heart disease, thyroid disease, and cognitive decline. It has been shown to affect immune system function and reproductive health.

Selenium deficiency can cause serious issues, such as infertility or amplification of certain viruses. In fact, Selenium deficiency's biggest threat is that it makes the body more susceptible to illness. These illnesses may be caused by stress related to nutritional or biochemical problems or by infection.

People at highest risk for Selenium deficiency include those who live in Selenium-deficient areas, are undergoing kidney dialysis, or are living with HIV. 

A word of caution about Selenium toxicity

The recommended dietary allowance (RDA) of Selenium is quite narrow -- the RDA is 55 to 70 micrograms per day. While we need a certain amount of Selenium, humans have a narrow range of tolerance for it, and it is harmful in excess. 

Scientific understanding of Selenium’s role in human health is still evolving. Recently some new epidemiologic and biochemical evidence has called into question earlier reports on cancer and cardiovascular risks. Extremely low selenium intake may drive up risk of a heart muscle disease (cardiomyopathy) called Keshan disease. On the other hand, high intake may increase risk of type 2 diabetes, thyroid status, and some specific melanoma and lymphoid cancers, among other concerns. 

Fortunately, Almeda’s liquid multivitamin Encarna was formulated to provide only the recommended daily amount of Selenium (70 mcg)... and no more than that. Many plant based ingredients help you not just survive but thrive in higher amounts, but we know that with Selenium, a little goes a long way.  

Diversifying what you eat day to day can help reduce the risk of Selenium toxicity.

Tracking and altering your levels of Selenium 

You can track your Selenium levels with the assistance of your healthcare provider, through blood or urine tests as well as tests done on hair and nail samples. 

The levels of Selenium in your bloodstream can be corrected. This can be done using specific supplements or sources of food. 

Plant foods are considered some of the best sources of Selenium because of their bioavailability. Specific foods naturally high in Selenium include Brazil nuts, tuna, halibut, sardines, ham, shrimp, and beef. Some breads, pastas, and grains are fortified or enriched with Selenium. If you are allergic to nuts, you don’t eat meat, or you are concerned about carbohydrates, supplementation may be a good option for you. 

Selected Food Sources of Selenium 

Food	Micrograms (mcg) per serving	Percent DV*
Brazil nuts, 1 ounce (6–8 nuts)	544	989
Tuna, yellowfin, cooked, dry heat, 3 ounces	92	167
Halibut, cooked, dry heat, 3 ounces	47	85
Sardines, canned in oil, drained solids with bone, 3 ounces	45	82
Ham, roasted, 3 ounces	42	76
Shrimp, canned, 3 ounces	40	73
Macaroni, enriched, cooked, 1 cup	37	67
Beef steak, bottom round, roasted, 3 ounces	33	60
Turkey, boneless, roasted, 3 ounces	31	56
Beef liver, pan fried, 3 ounces	28	51
Chicken, light meat, roasted, 3 ounces	22	40
Cottage cheese, 1% milkfat, 1 cup	20	36
Rice, brown, long-grain, cooked, 1 cup	19	35
Beef, ground, 25% fat, broiled, 3 ounces	18	33
Egg, hard-boiled, 1 large	15	27
Bread, whole-wheat, 1 slice	13	24
Baked beans, canned, plain or vegetarian, 1 cup	13	24
Oatmeal, regular and quick, unenriched, cooked with water, 1 cup	13	24
Milk, 1% fat, 1 cup	8	15
Yogurt, plain, low fat, 1 cup	8	15
Lentils, boiled, 1 cup	6	11
Bread, white, 1 slice	6	11
Spinach, frozen, boiled, ½ cup	5	9

Table Source: NIH. 

Summary

Selenium is a fascinating essential mineral. Our bodies need it, within a narrow range. Selenium deficiency carries many risks, most importantly that if we don't get the right amount, we may become more susceptible to illnesses. 

Almeda’s Encarna provides 100% of the recommended daily amount of selenium (70 mcg), but no more.