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Application of a new test for vitamin E deficiency to cystic fibrosis
1Department of Pediatrics, University of Texas Medical Branch, Galveston 77550-2776.
Insights
Cystic fibrosis patients may have vitamin E deficiency. A new functional test measuring erythrocyte malondialdehyde formation appears more reliable than plasma levels for assessing vitamin E status in these individuals.
Area of Science:
- Biochemistry
- Clinical Nutrition
- Pediatrics
Background:
- Cystic fibrosis (CF) patients with pancreatic insufficiency face a heightened risk of vitamin E deficiency.
- Vitamin E is crucial for antioxidant defense and cellular integrity.
- Conventional methods for assessing vitamin E status may be less reliable in specific pediatric populations.
Purpose of the Study:
- To evaluate vitamin E status in cystic fibrosis patients.
- To compare the efficacy of conventional vitamin E assessment methods with a novel functional test.
- To determine the most accurate method for diagnosing vitamin E deficiency in CF patients.
Main Methods:
- Screening of 13 cystic fibrosis patients using conventional measures (plasma vitamin E levels, vitamin E to lipid ratio).
- Assessment using a new functional test: in vitro erythrocyte malondialdehyde (MDA) formation.
- Comparison of patient results with age-matched healthy controls.
Main Results:
- Nine out of 13 CF patients were classified as vitamin E sufficient by both conventional and functional tests.
- Four CF patients identified as vitamin E deficient by conventional measures showed elevated in vitro erythrocyte MDA formation.
- The functional MDA test indicated potential vitamin E deficiency in some patients where plasma levels were borderline or normal.
Conclusions:
- Conventional plasma vitamin E levels and lipid ratios may not be sufficiently sensitive for detecting deficiency in CF patients.
- The in vitro erythrocyte malondialdehyde formation test offers a potentially more accurate functional assessment of vitamin E status in cystic fibrosis.
- Further validation of the functional MDA test is recommended for pediatric populations, especially in conditions like cystic fibrosis.
Abstract:
Cystic fibrosis patients with pancreatic insufficiency are at risk for the development of vitamin E deficiency. We report here the outcome of screening 13 cystic fibrosis patients with conventional descriptive measures of vitamin E status and a new functional test. The results were compared with those from age appropriate controls. Nine patients were found to be vitamin E sufficient based upon normal plasma vitamin E levels, the ratio of plasma vitamin E to total plasma lipids, and normal levels of in vitro erythrocyte malondialdehyde formation, the new functional measure of vitamin E status. Four patients considered vitamin E deficient, based upon low plasma vitamin E levels and plasma vitamin E to total plasma lipid ratios, demonstrated increased erythrocyte malondialdehyde formation in vitro when compared to age-matched controls. Since limited reference data in children are available to define normal plasma vitamin E levels and plasma vitamin E to total plasma lipid ratios, we suggest that for cystic fibrosis patients the functional in vitro malondialdehyde formation test may be a better measure of vitamin E status than static plasma levels.