The effect of selenium supplementation on skeletal and cardiac muscle in selenium-depleted patients

The purpose of the present study was to evaluate the effect of sodium selenite on skeletal and cardiac muscular function in patients with severe Se deficiency.

Skeletal and cardiac muscular function was investigated in 10 selenium depleted patients on long-term home parenteral nutrition because of short bowel syndrome. The following examinations were applied: Skeletal muscle biopsy, muscular force test (Kin-Com dynamometer test), electromyography (EMG) and radionuclide ventriculography. The patients were blindly randomized to intravenous supplementation with selenium 200 micrograms 5 to 7 times per week or placebo for 4 months. Hereafter the examinations were repeated. The patients randomized to placebo received selenium in an open study for a further 4 months and hereafter their skeletal and cardiac function was reevaluated.

Plasma selenium increased to normal levels from median .21 mumol/l (range 0-.69) to 1.25 mumol/l (range .9-2.27) following selenium repletion. The muscle biopsies showed only minor abnormalities. The only change after selenium supplementation was a small but statistically significant increase of the mean diameter of fiber type 1. The muscle strength of the quadriceps muscle was unchanged after selenium substitution. EMG did not reveal signs of myopathy. The cardiac function was normal and remained unchanged.

Despite severe selenium depletion ten patients on long term home parenteral nutrition had normal cardiac function, and no clinically significant signs of skeletal myopathy. The only change after selenium supplementation was a small but statistically significant increase of the mean diameter of muscle fiber type 1.