Selenium is an essential trace element associated with several biological functions, such as antioxidant defense, development, and support of the immune system. Cellular health lies in its binding to form an integral part of selenoproteins, which is a group of enzymes pertinent in providing antioxidant protection and regulating oxidative stress. Such proteins lessen free radical injury that, left unchecked, might impair organ function.
Selenium supports glutathione peroxidase, a powerful antioxidant enzyme that protects cells from oxidative damage. Selenium aids in the production and metabolism of thyroid hormones by converting thyroxine (T4) into its active form, triiodothyronine (T3). It boosts the immune response by promoting the activity of T-cells.
Selenium's antioxidant properties protect heart tissues from oxidative damage, maintaining their structure and function. A deficiency in selenium can lead to serious health problems, particularly affecting the thyroid gland, muscles, and the heart. Among these, the heart is notably at risk, as selenium deficiency is strongly linked to a rare but severe condition called Keshan disease.
Selenium deficiency and heart disease
The heart is particularly susceptible to selenium deficiency. The condition Keshan disease, named after a region in China where selenium levels in the soil are low, is a form of cardiomyopathy (heart muscle disease) caused by inadequate selenium intake. It is characterized by an enlarged heart, weakened heart muscles, and impaired cardiac function, which can lead to heart failure.
A 2021 study published in Frontiers in Pediatrics talks about Keshan disease a highly lethal cardiomyopathy, first reported in northeast China's Keshan County in 1935. The main symptoms of these two types of KD are chronic heart failure, arrhythmias, and ventricular or atrial fibrillation. "The Se status of heart, liver, kidney, and muscle compared with that of individuals with KD was up to 10-fold lower," the researchers have said.
Other organs that are critically affected by selenium deficiency
Thyroid glandSelenium is critical for converting inactive thyroid hormone (T4) into its active form (T3). Deficiency can lead to hypothyroidism, causing symptoms like fatigue, weight gain, and cold intolerance. Chronic selenium deficiency may increase the risk of thyroid disorders such as Hashimoto's thyroiditis.
MusclesSelenium deficiency can cause myopathy, or muscle weakness, due to oxidative damage to muscle cells. This manifests as difficulty in performing physical tasks or muscle pain.
Immune systemA lack of selenium weakens immune defenses, making the body more vulnerable to infections. It can impair the function of white blood cells, reducing the body’s ability to fight off pathogens.
BrainSelenium plays a role in reducing oxidative stress in the brain, which is critical for cognitive health. Deficiency has been linked to an increased risk of neurodegenerative diseases such as Alzheimer's.
