Selenium and Immune Function

Selenium is abundantly present in immune tissues such as the spleen, lymph nodes, and liver, playing critical roles in promoting T-cell proliferation, activating interleukin-2 (IL-2), and stimulating lymphocyte, macrophage, and killer cell production. Studies show that selenium deficiency impairs cell-mediated and B-cell immune functions, even rendering immune cells inactive. Remarkably, selenium supplementation in non-deficient individuals can still significantly enhance immunity.

Selenium and Antiviral Defense‌

Viral diseases are closely linked to selenium status. Deficiency both causes and exacerbates viral infections through four mechanisms:

1. Disrupting redox and immune regulation, promoting viral replication;

2. Increasing oxidative stress, elevating viral genome mutation rates;

3. Depleting selenium reserves during host antioxidant and immune responses;

4. Viral expression of selenoproteins competitively inhibits viral replication while suppressing host selenium availability. Emerging evidence suggests selenium status correlates with COVID-19 infection severity

Selenium and Cardiovascular Health

As an essential trace element, selenium deficiency impairs selenoenzyme synthesis, elevating oxidative stress and contributing to hypertension, coronary heart disease, and myocardial dysfunction. It mitigates cardiovascular risks by reducing inflammation, modulating nitric oxide levels, and preventing vascular calcification. Novel selenium supplements avoid the U-shaped association seen with traditional forms, optimizing preventive efficacy.

Selenium and Cancer

Selenium deficiency significantly increases risks of colorectal, prostate, lung, esophageal, and liver cancers. Selenium-protein complexes influence tumorigenesis through gene polymorphisms, serving as biomarkers for molecular subtyping and prognosis. Selenium compounds inhibit tumor proliferation and synergize with anticancer drugs.

Selenium's Antioxidant Role

Selenium’s primary biological function is antioxidant defense. As a core component of glutathione peroxidase (GSH-Px), it neutralizes reactive oxygen species, converts peroxides to harmless water/alcohol, and prevents lipid peroxidation, thereby protecting cellular integrity and delaying aging. GSH-Px deficiency severely compromises antioxidant capacity, accelerating disease progression.

Scientific Supplementation Guidelines

Daily intake: 55–400 μg (adults); excess causes toxicity (e.g., hair loss, nail brittleness).

Food sources: Brazil nuts, seafood, organ meats, whole grains.

Clinical use: Selenium yeast supplements under medical supervision for deficiencies.

For personalized advice, consult healthcare professionals to tailor selenium intake based on individual needs.