Selenium

Selenium is a trace element that is crucial for various physiological functions in the human body. It serves as an essential component of selenoproteins, which have antioxidant properties and play roles in DNA synthesis, immune function, and thyroid hormone metabolism. While selenium is necessary for health, excessive intake can be harmful. It is obtained through dietary sources, and its optimal levels are vital for overall well-being.

Overview

Trace Element:

Essential Nutrient: Selenium is an essential trace element required for the proper functioning of the human body.

Selenoproteins: It is a key component of selenoproteins, a family of proteins containing selenium in the form of the amino acid selenocysteine.

Antioxidant Properties:

Cellular Defence: Selenium's antioxidant properties help protect cells from oxidative stress.

Functions of Selenium

Antioxidant Defence:

Selenoproteins: Selenium is a component of various selenoproteins, including glutathione peroxidases, which neutralize reactive oxygen species.

Thyroid Hormone Metabolism:

Conversion of T4 to T3: Selenium is involved in the conversion of thyroxine (T4) to triiodothyronine (T3), active thyroid hormones.

DNA Synthesis and Repair:

Genomic Stability: Selenium plays a role in DNA synthesis and repair, contributing to genomic stability.

Immune Function:

Immune Response: Selenium is important for the proper functioning of the immune system.

Male Reproductive Health:

Spermatogenesis: Selenium is involved in male reproductive health, specifically in spermatogenesis.

Dietary Sources of Selenium

Seafood:

Fish: Tuna, halibut, sardines, and shrimp.

Shellfish: Oysters, crab, and mussels.

Meat and Poultry:

Beef, Pork, Chicken: Meat and poultry are good sources of selenium.

Brazil Nuts:

High Selenium Content: Brazil nuts are particularly rich in selenium, but consumption should be moderate due to the risk of excessive intake.

Eggs:

Selenium-Rich Eggs: Eggs, especially those from chickens fed selenium-rich diets.

Grains and Seeds:

Brown Rice, Sunflower Seeds: Some grains and seeds contain selenium.

Recommended Daily Intake

Varied Requirements: The recommended daily intake varies by age, sex, and life stage. For adults, it is generally around 55 micrograms.

Deficiency and Excess

Deficiency Symptoms:

Keshan Disease: Severe selenium deficiency may contribute to Keshan disease, a form of cardiomyopathy.

Excess Intake:

Selenosis: Excessive selenium intake, usually from supplements, can lead to selenosis, characterized by symptoms such as hair and nail loss, gastrointestinal issues, and neurological problems.

Interactions and Considerations

Interactions with Other Nutrients:

Iodine: Adequate selenium levels are important for optimal thyroid function in the presence of iodine.

Medical Conditions:

Thyroid Disorders: Individuals with thyroid disorders may have specific considerations regarding selenium intake.

Research and Health Benefits

Cancer Prevention:

Anticancer Properties: Some studies explore the potential link between adequate selenium levels and a reduced risk of certain cancers.

Cardiovascular Health:

Heart Disease Prevention: Research suggests that optimal selenium levels may contribute to cardiovascular health.