Vitamin E and neurological function.

The clinical, neuropathological and electrophysiological evidence that vitamin E (alpha-tocopherol) is essential for normal neurological function will be reviewed. The possible reasons why neural tissues should be particularly affected by a deficiency of this fat-soluble vitamin and the mechanism(s) involved will be considered.

Supplementation with antioxidants and folinic acid for children with Down's syndrome: randomised controlled trial.

OBJECTIVES: To assess whether supplementation with antioxidants, folinic acid, or both improves the psychomotor and language development of children with Down's syndrome. DESIGN: Randomised controlled trial with two by two factorial design. SETTING: Children living in the Midlands, Greater London, and the south west of England. PARTICIPANTS: 156 infants aged under 7 months with trisomy 21. INTERVENTION: Daily oral supplementation with antioxidants (selenium 10 mug, zinc 5 mg, vitamin A 0.9 mg, vitamin E 100 mg, and vitamin C 50 mg), folinic acid (0.1 mg), antioxidants and folinic acid combined, or placebo. MAIN OUTCOME MEASURES: Griffiths developmental quotient and an adapted MacArthur communicative development inventory 18 months after starting supplementation; biochemical markers in blood and urine at age 12 months. RESULTS: Children randomised to antioxidant supplements attained similar developmental outcomes to those without antioxidants (mean Griffiths developmental quotient 57.3 v 56.1; adjusted mean difference 1.2 points, 95% confidence interval -2.2 to 4.6). Comparison of children randomised to folinic acid supplements or no folinic acid also showed no significant differences in Griffiths developmental quotient (mean 57.6 v 55.9; adjusted mean difference 1.7, -1.7 to 5.1). No between group differences were seen in the mean numbers of words said or signed: for antioxidants versus none the ratio of means was 0.85 (95% confidence interval 0.6 to 1.2), and for folinic acid versus none it was 1.24 (0.87 to 1.77). No significant differences were found between any of the groups in the biochemical outcomes measured. Adjustment for potential confounders did not appreciably change the results. CONCLUSIONS: This study provides no evidence to support the use of antioxidant or folinic acid supplements in children with Down's syndrome. TRIAL REGISTRATION: Clinical trials NCT00378456.

Effects on neural function of repleting vitamin E-deficient rats with alpha-tocopherol.

A severe and chronic deficiency of vitamin E (alpha-tocopherol) is associated with a characteristic neurological syndrome with typical "clinical," neuropathological, and electrophysiological abnormalities in both humans and experimental animals. Repletion of vitamin E-deficient human subjects with alpha-tocopherol typically halts the progression of the neural signs and symptoms, and in some cases, can result in objective improvement. Electrophysiological parameters provide an objective measure of neural and visual function and improvement of some of these measures has been reported after repletion with vitamin E in humans. In this longitudinal study, the effects of repleting rats with a diet containing 36 mg/kg all-rac-alpha-tocopheryl acetate for 20 wk after they had been receiving a vitamin E-deficient diet for 38 wk was studied. We report significant improvements in growth and a number of electrophysiological parameters of both neural and visual function after repletion. These results confirm the validity of the vitamin E-deficient rat as a model of vitamin E deficiency in humans.

Dietary lipids and vascular function: UK Food Standards Agency workshop report.

The UK Food Standards Agency convened a group of expert scientists to review current research investigating the effect of dietary lipids on vascular function. The workshop highlighted the need for intervention studies to be sufficiently powered for these measures and that they should be corroborated with other, more validated, risk factors for CVD. Work presented at the workshop suggested a beneficial effect of long-chain n-3 PUFA and a detrimental effect of trans fatty acids. The workshop also considered the importance of the choice of study population in dietary intervention studies and that "at risk" subgroups within the general population may be more appropriate than subjects that are unrepresentatively healthy.

Synthesis and analysis of conjugates of the major vitamin E metabolite, alpha-CEHC.

Glucuronide and sulphate conjugates of 2,5,7,8-tetramethyl-2-(2'-carboxyethyl)-6-hydroxychroman (alpha-CEHC), the major metabolite of alpha-tocopherol (vitamin E), have been synthesized and used for the first direct analysis of conjugated urinary vitamin E metabolites. The metabolites of vitamin E (alpha-tocopherol) could be useful as markers of the function(s) of vitamin E in vivo. A number of methods have been described for the analysis of urinary vitamin E metabolites but these have relied on either acid or enzymatic deconjugation of the metabolites prior to analysis by high performance liquid chromatography or gas chromatography/mass spectrometry. These methods have provided useful information about the amount and types of metabolites excreted in the urine but suffer from a number of disadvantages. Deconjugation has been shown to produce artifacts as a result of the conversion of alpha-CEHC to alpha-tocopheronolactone and the efficiency of deconjugation is also difficult to assess. Methods that allow the direct measurement of the conjugated metabolites would overcome these problems and would also substantially reduce the preparation and analysis time. Here we describe the use of conjugated standards to characterize alpha-CEHC conjugates in human urine by tandem mass spectrometry (MS-MS). The future use of MS-MS to measure urinary vitamin E metabolites is also discussed.