Selenium

Selenium is a vital microelement-an antioxidantthat is part of more than 25 proteins (selenoproteins). Its main functions are:

1. Antioxidant protection:

• It is a part of glutathione peroxidase , an enzyme that neutralizes free radicals.

1. Thyroid Support:

• It is involved in the conversion of the hormone T4 (thyroxine) to T3 (triiodothyronine).

1. Immunity:

• Increases the activity of NK cells and T-lymphocytes.

1. Detoxification:

• Binds heavy metals (mercury, cadmium).

1. Reproductive health:

• It is necessary for sperm motility in men.

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Symptoms of selenium deficiency

Deficiency occurs in regions with a low content of selenium in the soil (for example, some areas of China and Russia).

Main features:

• Weakness, muscle aches (due to oxidative stress).
• Violation of the thyroid gland (hypothyroidism, goiter).
• Reduced immunity (frequent infections).
• Infertility in men (oligospermia).
• Keshan’s disease (cardiomyopathy, found in endemic areas).

Risk groups:

• Vegans/vegetarians (exclude meat, fish).
• People with Crohn ‘s disease or celiac disease (malabsorption).
• Residents of regions with a selenium deficiency in the soil.

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Symptoms of excess selenium (selenosis)

Overdose is possible with prolonged supplementation (>400 mcg / day).

Signs:

• Garlic breath odor (release of dimethyl selenide).
• Hair loss, brittle nails.
• Nausea, diarrhea.
• Neurological disorders (irritability, tremor).

Dangerous doses:

• > 900 mcg / day – risk of acute poisoning (vomiting, liver damage).

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Selenium standards in analyses

The selenium level is determined in:

1. Blood (serum/plasma) — reflects the current intake.
2. In the urine – shows a long-term balance.
3. Hair/nails – accumulation over several months.

Reference values:

Critical levels:

• < 50 mcg/l (blood) — deficiency.
• > 200 mcg / l (blood) – excess.

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When is the test scheduled?

1. Suspected selenium deficiency/excess.
2. Hypothyroidism of unknown origin.
3. Male infertility.
4. Living in endemic regions.

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How to normalize selenium levels?

If there is a shortage:

• Products:
• Brazil nuts (1 nut = 50-100 mcg).
• Tuna, eggs, liver, garlic.
• Supplements:
• Selenomethionine (100-200 mcg / day).

If there is an excess:

• Cancellation of supplements.
• Increase the intake of sulfur-containing amino acids (methionine, cysteine) for detoxification.

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Examples of deviations

• Selenium = 40 mcg / l (blood) + hypothyroidism → taking selenomethionine 100 mcg / day.
• Selenium = 250 mcg / l + hair loss → elimination of dietary supplements.

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Conclusion

Selenium is a key antioxidant and thyroid regulator.
Rules:

• Blood: 70-150 mcg/l,
• Urine: 20-100 mcg/l
  . Дефицит Deficiency causes weakness, hypothyroidism, and immunodeficiency.
  Excess (>200 mcg/l – — toxic (damage to hair, nails, nervous system).
  Optimal dose: 50-200 mcg / day (from food or supplements).

Important: Brazil nuts are record holders for selenium, but 2-3 pieces a day is enough!