AUGUSTA, Ga. — According to new research released Tuesday, Georgia Health Sciences University researchers have identified one of the internal bodily functions of vitamin E: The antioxidant found in most foods helps repair tears in the plasma membranes that protect cells from outside forces and screen what enters and exits.
"Without any special effort, we consume vitamin E every day and we don't even know what it does in our bodies," stated Paul McNeil, GHSU cell biologist and the study's corresponding author. Century-old animal studies linked vitamin E deficiency to muscle problems, but how that happens remained a mystery until now, McNeil said. His understanding that a lack of membrane repair caused muscle wasting and death prompted McNeil to look at vitamin E.
Such everyday activities as eating and exercise can tear the plasma membrane, and the new research shows that vitamin E is essential to repair. Without repair of muscle cells, muscles eventually waste away and die in a process similar to what occurs in muscular dystrophy. Muscle weakness also is a common complaint in diabetes, another condition associated with inadequate plasma membrane repair.
Vitamin E appears to aid repair in several ways. As an antioxidant, it helps eliminate destructive byproducts from the body's use of oxygen that impede repair. Because it's lipid-soluble, vitamin E can actually insert itself into the membrane to prevent free radicals from attacking. It also can help keep phospholipids, a major membrane component, compliant so they can better repair after a tear.
For example, exercise causes the cell powerhouse, the mitochondria, to burn significantly more oxygen than usual. "As an unavoidable consequence, you produce reactive oxygen species," McNeil said. The physical force of exercise tears the membrane. Vitamin E enables adequate plasma membrane repair despite the oxidant challenge and keeps the situation in check.
When he mimicked what happens with exercise by using hydrogen peroxide to produce free radicals, he found that tears in skeletal muscle cells would not heal unless pretreated with vitamin E.
The research was reported in the journal Nature Communications.
Next steps, which will be aided by two recent National Institutes of Health grants, include examining membrane repair in vitamin E-deficient animals.