Selenium

Selenium deficiency impairs natural killer cell activity, T-cell proliferation and antibody responses, and increases susceptibility to viral infection, partly through loss of glutathione peroxidase and thioredoxin reductase protection of immune cells. Supplementation improves immune measures mainly in people with low baseline selenium status; benefits in replete individuals are not established.

168 Hashimoto patients with TSH 3-6; myo-inositol plus selenium lowered TSH, TPOAb and TgAb more than selenium alone.

Protective associations were concentrated in populations with low baseline selenium, while trials in selenium-replete populations showed no cancer benefit. The dose-response appears U-shaped, with plausible benefit in the region of 100-200 mcg daily and evidence of harm, including raised type 2 diabetes risk and selenosis, at higher intakes. Baseline status, not dose alone, determines whether supplementation is plausible.

Pooled analysis of randomized trials found selenium 200 mcg/day reduced thyroid peroxidase antibody titres in Hashimoto's thyroiditis at 3-12 months, with the largest reductions in patients not on levothyroxine; effects on thyroid hormone levels, symptoms and quality of life were inconsistent or absent.

Review of selenium biology: selenium is incorporated into around 25 selenoproteins including glutathione peroxidases and thioredoxin reductases. Status varies widely by soil geography, and both deficiency and excess carry risk, with a narrow optimal intake window and a U-shaped risk curve for several outcomes.

Review of mineral status in alcohol use disorder found consistently low magnesium, zinc and selenium levels and frequently disturbed calcium, potassium, sodium and phosphate balance, driven by poor intake, gastrointestinal losses, renal wasting and liver dysfunction; deficiencies were linked to withdrawal severity, neuropathy, arrhythmia risk and refeeding complications.

Cochrane review of 28 trials (about 83,000 cognitively healthy adults) found no evidence that vitamin or mineral supplementation - including B vitamins, antioxidant vitamins C and E, beta-carotene, selenium, zinc or multivitamins - preserves cognitive function in mid or late life; the only weak signals (beta-carotene and selenium after many years) were of doubtful clinical significance.

Total sperm concentrations were increased by selenium (3.91 x 10^6 spz/mL; 3.08, 4.73 spz/mL)

Selenium supplementation reduced oxidative DNA damage in adnexectomized BRCA1 mutation carriers.

The analysis revealed that minerals like selenium, zinc, and copp

In people with HT without THRT, selenium was effective and safe in lowering TSH, TPOAb, and MDA levels.

Selenium 200 mcg/day did not prevent prostate cancer, and a non-significant increase in type 2 diabetes risk was observed in the selenium arm.

Selenium supplementation suppressed HIV-1 viral load and raised CD4 count.

significant improvement in semen parameters for selenium (200µg/day and 100µg/day) (standard mean difference [SMD] 0.64 for oligozoospermia, 1.39 for asthenozoospermia)

Selenium administration significantly improved quality of life, reduced ocular involvement, and slowed progression of the disease in patients with mild Graves' orbitopathy.

Antioxidant supplements did not reduce mortality in primary and secondary prevention trials

The primary objective was to measure the effect of selenium (as selenomethionine) on colorectal adenomas occurrence

Although some of the data suggested beneficial effects of selenium supplementation on immune function, the overall picture appears to be inconsistent.

Selenium supplementation showed no benefit on prostate cancer risk compared with placebo.

Selenium produced no consistent improvement in natural killer cell activity in already replete men

Subfertile couples should be advised that overall, the current evidence is inconclusive based on serious risk of bias.

No clinical benefit could be demonstrated from active treatment. There are several possible explanations for this negative result, including the short duration of therapy. It is possible that antioxidant therapy, to be effective, needs to be given early in the SSc disease process, before the onset of irreversible tissue damage.

There was no difference in pain scores, quality of life or analgesic use between antioxidant and placebo groups.

Randomised evidence shows no reduction in cancer incidence or mortality with selenium supplementation, alongside increased risk of type 2 diabetes.

Selenium supplementation did not improve QOL or clinical parameters in patients with mild to moderate GO in selenium-sufficient regions at 6 months.

a randomized trial of selenium (200 micro g daily) designed to test the hypothesis that selenium supplementation (SS) could reduce the risk of recurrent nonmelanoma skin cancer among 1312 residents of the Eastern USA

SYT treatment significantly decreased TPOAb, TGAb, and thyroid stimulating hormone (TSH) levels compared with the control group.

Se testing should be considered as soon as cardiac involvement is suspected. VitC testing should be considered in malnourished SSc patients, especially if skin involvement is extensive.

Antioxidant supplementation, including selenium, was associated with improved fertility outcomes in subfertile men, on low-quality evidence.

Selenium supplements did not reduce cardiovascular events or all-cause mortality.

At 6 months, patients on selenium supplementation were more likely than controls to show improved thyroid function; however, the effect disappeared at 9 months.

The use of selenium supplements was able to significantly reduce the levels of thyroid peroxidase autoantibodies (TPOAb).

Sperm motility, morphology or both improved in 52.6% of treated men

Selenium reduced thyroid peroxidase antibody levels at 3, 6 and 12 months in autoimmune thyroiditis, with unclear effect on clinical thyroid function.

Selenium supplementation increased T-cell proliferation and accelerated poliovirus clearance compared with placebo

Adding L-Carnitine and Selenium to Methimazole in Graves' Disease: A Prospective Randomized Trial on Thyroid Markers and Quality of Life.

Some studies have suggested a protective effect of antioxidant nutrients and higher dietary levels of fruits and vegetables on lung cancer.

Selenium provided no protective benefit against prostate cancer

Selenium reduced prostate cancer incidence only in men in the lowest tertile of baseline plasma selenium.

Extended follow-up showed vitamin E increased prostate cancer risk by 17 percent, while selenium alone conferred no protection.