Selenium is an essential trace mineral that plays a critical role in several important bodily functions. It acts as a powerful antioxidant, helping to protect cells from damage caused by free radicals. Selenium is also vital for the proper functioning of the immune system, thyroid hormone metabolism, and the production of DNA. Additionally, selenium supports cognitive function and plays a role in reducing inflammation.
Selenium is a trace mineral needed for the production of the antioxidant enzyme glutathione peroxidase. It is primarily needed for immune system health; antioxidant protection; liver health; heart health and joint care; thyroid hormone production, male fertility and prostate protection.
Functions of Selenium
| Function | How it Helps |
|---|
| Antioxidant | Selenium is an important component of glutathione peroxidase, which protects cells from free radical damage. It also acts with vitamin E as an antioxidant, protecting fats and cell membranes. |
| Detox and Liver Support | Glutathione is needed by the liver to help eliminate toxic compounds from the body. Selenium binds to mercury, helping to protect against its toxic effects. |
| Cardiovascular Health | Selenium helps maintain the correct balance of HDL and LDL cholesterol, protects against excessive blood clotting, and reduces cholesterol deposits. It also works with vitamin E to prevent oxidation of fat and cholesterol in the arteries. |
| Immune Health | Low selenium levels weaken the function of the thymus (the master gland of immunity) and suppress white blood cell activity. |
| Thyroid Function | Selenium is essential for the synthesis of thyroid hormones, supporting healthy thyroid function and regulating metabolism. |
| Reproductive Health | Selenium contributes to sperm production and overall fertility in both men and women. |
| DNA Synthesis | Selenium plays a role in DNA synthesis and repair, helping maintain genetic integrity and prevent mutations that could lead to cancer. |
Here’s a list of the benefits of taking the right amount of selenium:
- Antioxidant Protection: Helps neutralize free radicals, reducing oxidative stress and protecting cells from damage.
- Boosts Immune Function: Supports the immune system by enhancing white blood cell activity and improving the body’s ability to fight infections.
- Thyroid Health: Essential for the synthesis of thyroid hormones, helping regulate metabolism and supporting overall thyroid function.
- Cardiovascular Health: Supports a healthy balance of HDL and LDL cholesterol, reduces cholesterol deposits, and prevents the oxidation of fat and cholesterol in arteries.
- Detoxification Support: Helps the liver eliminate toxins and protects against the toxic effects of mercury.
- Reproductive Health: Contributes to sperm production and fertility in both men and women.
- DNA Repair and Synthesis: Plays a critical role in maintaining genetic integrity, preventing mutations, and reducing the risk of certain cancers.
- Cognitive Health: May help protect against cognitive decline and support brain function, especially as you age.
- Reduced Inflammation: Supports anti-inflammatory processes, potentially reducing the risk of chronic diseases linked to inflammation.
- Prevention of Selenium Deficiency: Ensures adequate selenium levels to avoid health issues like fatigue, muscle weakness, and weakened immunity.
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What is it used for?
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|---|---|---|
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Protection against free radicals |
Cardiovascular health | Immune dysfunction |
| Liver protection | Arthritis and various other inflammatory conditions |
Elimination of and/or protection against heavy metals (i.e. cadmium, mercury, lead) |
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Male fertility problems |
Cell protection |
Detoxification |
What foods are high in selenium?
Selenium is found in a variety of foods, with the highest concentrations typically found in Brazil nuts, which contain an exceptionally high amount of the mineral. Other good dietary sources include seafood such as tuna, shrimp, and salmon, as well as meats like turkey, chicken, and beef. Whole grains, eggs, dairy products, and certain vegetables (like spinach and broccoli) also provide selenium, though in smaller amounts.
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Best food sources
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|---|---|---|
| Brazil nuts | Butter | Liver |
| Shellfish | Fish | Apple cider vinegar |
| Whole wheat | Oats | Brown rice |
| Yeast | Milk | |
How much selenium is in one egg?
A single large egg contains about 15 micrograms of selenium, which represents around 20-25% of the recommended daily intake for most adults. While eggs are not the highest source of selenium compared to some other foods, they can still contribute to overall intake, especially when part of a balanced diet.
What happens if selenium is too high?
While selenium is essential for good health, too much can be harmful. High levels of selenium, a condition known as selenosis, can cause symptoms like garlic-smelling breath, nausea, diarrhea, hair loss, fatigue, and irritability. In severe cases, it may lead to more serious issues like kidney failure, heart problems, or neurological damage. It’s important to stay within the recommended daily intake and avoid excessive supplementation.
How do I know if I need more selenium?
If you are concerned about your selenium levels, it is best to consult a healthcare provider. Blood tests can measure selenium levels, and your doctor may recommend dietary adjustments or supplements if needed. Individuals at higher risk of deficiency include those with certain medical conditions (such as gastrointestinal disorders) or those who have a limited diet low in selenium-rich foods.
What are the signs of selenium deficiency?
A deficiency in selenium can lead to a range of health issues, including a weakened immune system, fatigue, and cognitive dysfunction. In more severe cases, selenium deficiency may cause Keshan disease, a type of heart disease, or Kashin-Beck disease, which affects joints and bones. Symptoms of deficiency can also include hair loss, brittle nails, and muscle weakness.
Deficiency Symptoms |
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|---|---|---|
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Liver necrosis |
Psoriasis eczema |
Eye problems |
| Cardiomyopathy | Toxic overload | Immunity problems |
| Arthritis | Heavy metal toxicity | Thryoid disfunction |
Factors which deplete levels, impair absorption and/or inhibit activity: |
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|---|---|---|
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Vitamin C in very high doses |
Zinc in very high doses |
Heavy metals, (lead, mercury, cadmium) |
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Chemotherapy drugs |
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Supplementation dosage range
50-400ug per day
The recommended dietary allowance (RDA) for selenium is about 55 micrograms per day for adults, with variations for pregnant and lactating women8. While selenium is crucial for health, excessive intake can lead to toxicity, so it is important to consume it within recommended limits.
In summary, selenium is vital for protecting cells from damage, supporting thyroid function, enhancing immune responses, aiding reproductive health, and facilitating DNA synthesis.
Other information
Deficiency is common in many parts of the world, including the UK due to poor soil levels of selenium Deficiency can cause heart muscle wastage and joint inflammation and it is strongly linked to increased risk of cancer, heart diseases and other degenerative diseases.
Generally it is recommended for its antioxidant protective effects against diseases such as heart and brain disorders, joint disease, liver conditions and cancers.
Selenium and vitamin E enhance each others antioxidant properties.
Cautions
Yeast-derived selenium supplements should not be used by patients taking monoamine oxidase (MAO) inhibitors unless on the advice and under the strict monitoring of a physician. Yeast-free selenium supplements can be used as an alternative.
Selenium supplementation at very high doses can cause problems with nails and hair, but the levels in typical supplements do not pose a problem.
