[The oral vitamin E tolerance test--an attempt at standardization]

Chronic vitamin E deficiency causes various neurological symptoms such as cerebellar ataxia, hypoesthesia, areflexia, pigmentary retinopathy, nystagmus and muscle weakness. This is commonly caused by malabsorption of vitamin E, which is either a result of malabsorption of fat or occurs as an isolated vitamin E deficiency. The oral vitamin E tolerance test is suitable for the assessment of vitamin E reabsorption and elimination. However, standardised normal parameters have not yet been defined. We investigated 61 healthy individuals aged 18-70 years (mean age, 45.0 years). Each person involved in the trial received 100 IU of all-rac-alpha-tocopherol in 200 millilitres of whole milk. The vitamin E in the serum was then analysed 0, 3, 6, 9, 12, 24, 36, 48, 60, 72 hours after vitamin E was given, using high pressure liquid chromatography. The ratio of vitamin E to the sum of cholesterol and triglycerides was calculated. The 90% CI for the ratio of serum vitamin E to the sum of cholesterol plus triglycerides at the indicated time points was: t = 0 h: 2.0-6.3 micrograms/mg, t = 6 h: 4.2-15.3 micrograms/mg, t = 12 h: 3.0-13.0 micrograms/mg, t = 24 h: 3.8-14.4 micrograms/mg, t = 36 h: 2.9-10.5 micrograms/mg, t = 72 h: 2.1-8.7 micrograms/mg. The serum concentration of vitamin E correlated predominantly with the sum of cholesterol and triglycerides (r = 0.73). The ratio of these parameters is therefore most suitable for diagnosing vitamin E deficiency without relying on false normal serum vitamin E concentrations as a result of abnormally high serum lipid concentrations.