Vitamin E refers to molecules that exhibit the biological activity of alpha- tocopherol. Alpha tocopherol is the most abundant form of vitamin E in the body.
The tocopherols are carried in the blood by lipids. The ratio of tocopherol to lipid provides a better estimate of vitamin-E status than tocopherol alone. Adequate vitamin-E status is depicted by a level of approximately 0.8 mg total tocopherol per gram of total lipids.
This is a functional test of the rate of hemolysis, based on the ability of hydrogen peroxide to liberate hemoglobin from red cells. Hemolysis of over 10% is associated with vitamin-E deficiency, though it is not clear whether the assay is indicative of alpha-tocopherol body stores or blood stores only.
Pentane and ethane are gases exhaled in the breath as a by-product of the peroxidation of linolenic acid and linoleic acid. A negative correlation has been found in children between plasma vitamin-E levels and breath pentane. Breath pentane and ethane levels also increase in cases of vitamin-C and beta-carotene deficiency.