Selenium: Crucial for Good Health

Autoimmunity & Healing Diets

Jul 04

Found in soil, selenium is a trace mineral which is critical for good health. Important as an anti-oxidant, selenium prevents cell damage from free radicals. I have written a lot about free radicals and anti-oxidants because I believe that free radical damage is part of the basic problem in chronic health conditions. Selenium is incorporated into proteins to make selenoproteins that are required for many metabolic reactions in the body. Deficiency can contribute to cancers and other chronic problems.

Selenium is of the soil

The selenium content in food depends on the selenium content of the soil in which plants are grown or animals graze. We know that the soil in the high plains of northern Nebraska and the Dakotas have very high levels of selenium. People living in those regions generally have the highest selenium intakes in the United States. Interestingly, researchers found that people living in these high selenium areas did not suffer from any selenium toxicity even when intake was as high as 724 micrograms per day (the Recommended Daily Intake for adults is between 50 and 200 mcg).

Soil in some parts of China and Russia have very low amounts of selenium and selenium deficiency is often reported in those regions. In the U.S. low selenium areas are usually compensated for because of the way food is grown and transported here. I guess that is one good thing about distributing food all across the country as opposed to local economies — any deficiencies are balanced by the food from outside of the immediate area.

Selenium content of food

By far the best source of selenium is brazil nuts which can have up to 544 mcg per ounce, which would give you many times the recommended daily value. The next best sources are tuna with 68 mcgs per 3 ounces, cod, turkey, chicken breast and chuck roast at 20 – 30 mcg per 3 ounces and sunflower seeds at 23 mcg per 1 ounce.

Of course these values will change with the selenium content of the soil and food these animals are exposed to. Selenium is also found in eggs, ground beef, oatmeal, cottage cheese, and rice.

Selenium deficiency

With selenium deficiency comes a greater susceptibility to a form of heart disease, thyroid disease and a weakened immune system which increases cancer risk. While selenium deficiency is rare, if the soil is lacking selenium, whole populations may be affected.

There are three specific diseases that are associated with selenium deficiency:

  • Keshan Disease, which results in an enlarged heart and poor heart function. This occurs in selenium deficient children and has been seen in China.
  • Kashin-Beck Disease, which results in osteoarthropathy or joint disease.
  • Myxedematous Endemic Cretinism, which results in mental retardation.

Other instances of selenium deficiency may occur in people with gastrointestinal disorders that impair selenium absorption such as, Crohn’s disease, Celiac disease or ulcerative colitis, as well as people who have been on total parenteral nutrition (TPN) for their source of nutrition. It may also occur in people who have had surgical removal of part of the stomach.

Selenium and thyroid disease

Another important condition related to selenium deficiency is thyroid disease. People with iodine deficiency may also benefit from selenium supplementation. While public health officials consider iodine deficiency to be rare in this country,  Dr. David Brownstein has researched and written several books about thyroid disorders and iodine deficiency. He feels that it is widespread in this country and is the cause of many disorders.

In relationship to the thyroid, iodine is very important. However, here is an important fact — Selenium is essential for the biosynthesis and function of a small number of selenocysteine-containing selenoproteins involved in thyroid hormone metabolism and gland function.

Additionally, three different selenium-dependent iodothyronine deiodinases (types I, II, and III) can both activate and inactivate thyroid hormones, making selenium an essential micronutrient for normal development, growth, and metabolism. (Source)

Selenium is a powerful anti-oxidant

While it is not absolutely clear, there is much research which indicates that selenium may affect cancer risk in two ways.

  1. As an anti-oxidant, selenium can help protect the body from the damaging effects of free radicals.
  2. Selenium may also prevent or slow tumor growth. Metabolic byproducts of selenium are believed to prevent tumor growth by enhancing immune cell activity and suppressing development of blood vessels to the tumor. Without blood vessels, tumors cannot grow.

Additionally, selenium is an important constituent of the enzyme glutathione peroxidase, which is responsible for destroying lipid-damaging peroxides. In this role, selenium complements the anti-oxidant function of vitamin E.

The enzyme glutathione peroxidase is contained within white blood cells and blood platelets, and is important for immune system function as well as its anti-oxidant activity.

Selenium and cancer

There are quite a few observational studies which indicate that death from cancer, including lung, colorectal, and prostate cancers, is lower among people with higher blood levels or intake of selenium.

Additionally, the incidence of basal/squamous cell skin cancer is significantly higher in areas of the United States with low soil selenium content. The effect of selenium supplementation on the recurrence of different types of skin cancers was studied in seven dermatology clinics in the U.S. from 1983 through the early 1990s. Taking a daily supplement containing 200 mcg of selenium did not affect recurrence of skin cancer, however, it significantly reduced the occurrence and death from total cancers. The incidence of prostate cancer, colorectal cancer, and lung cancer was notably lower in the group given selenium supplements.

While there are other studies that indicate no benefit on cancer from taking selenium supplements, there are enough that do indicate benefit to make it a substance of great interest in cancer research.

Selenium and heart disease

Some research has suggested an association between lower antioxidant intake and a greater incidence of heart disease. Also suggested is that oxidative stress from free radicals, which are natural by-products of oxygen metabolism, may promote heart disease.

It is the oxidized form of low-density lipoproteins (LDL, often called “bad” cholesterol) that promotes plaque build-up in coronary arteries — not just the presence of LDL. Selenium is one of a group of antioxidants that may help limit the oxidation of LDL cholesterol and thereby help to prevent coronary artery disease. More research is necessary to document this hypothesis.

Selenium and arthritis

Research indicates the people with rheumatoid arthritis have low levels of selenium. People with autoimmune conditions have inflammation and free radical tissue damage. Anti-oxidants like selenium may help to control levels of free radicals. Here too, further research is needed to confirm this.

Not all selenium is the same

The best way to get selenium is from food. However, it is extremely dependent on the selenium content of the soil. There are many areas in this country that have selenium deficient soil — especially since much of the soil is damaged by years of chemical fertilizers, pesticides and herbicides. These chemicals bind up minerals in the soil and make them unavailable.

Selenomethionine

Selenomethionine is considered a good form of organic selenium to take as a supplement. However, supplements are synthesized in a laboratory.

When absorption of inorganic selenium (sodium selenite) is compared to organic selenium (selenomethionine), the organic selenium proves to be best. In a study of ewes and lambs, this is exactly what they found. They found that, organic selenium supplementation increased selenium concentrations in ewe and newborn lamb blood and in slaughter lamb meat compared to inorganic selenium supplementation.

However, there is an even better form of selenium — one that is found in spirulina — one that is made by the bacteria itself. This is a natural form of selenium and has been found to be extremely absorbable by humans. This form is selenium-rich spirulina which is then dried, powdered and encapsulated as a whole, raw food supplement. It is by far the best source of selenium to be found because it is in its whole raw form and highly bioavailable.

Where to buy a selenium supplement

Where to buy a spirulina supplement

Where to buy the book, Iodine: Why You Need It , Why You Can’t Live Without It  by Dr. David Brownstein

Where to buy the book, Overcoming Thyroid Disorders  by Dr. David Brownstein

Source

This post is shared at: Simple Lives Thursday, Friday Food, Foodie Friday, Fight Back Friday, Fresh Bites Friday, Sunday Celebration, Sugar Free Sunday, Monday Mania, Barnyard Hop, Meatless Monday, Tasty Tuesday Naptime, Hearth & Soul Hop, Traditional Tuesday, Whole Foods Wednesday, Healthy 2Day, Real ood Wednesday, Allergy Free Wednesday, Mommy Club, Sustainable Ways

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