Vitamin E Pharmacokinetics and Biomarkers in Normal and Obese Women

Summary

Background: * Vitamin E is an antioxidant that reduces the damaging effects of oxygen in the body. Most American men (90%) and women (96%) do not get enough vitamin E from their diets; however, the amount of vitamin E needed by the body has been studied only in men, not women. In addition, it is unknown whether another antioxidant, vitamin C, helps vitamin E in protecting the body. Because vitamin E is a fat-soluble vitamin, how much body fat a person has could affect the amount of vitamin E needed for protection. Objectives: This study has three arms to examine vitamin E requirements: * To determine the amount of fat required to get the best vitamin E absorption from a meal. * To determine the amount (i.e., best dose) of vitamin E that must be consumed before it can be measured in the blood. * To examine how vitamin E and vitamin C work together in the body, in conjunction with diet and vitamin supplements. Eligibility: * Arms 1 and 2: Women between the ages of 18 and 40 years who have a normal weight and body mass index (BMI) of 27 or less. * Arm 3: Women between the ages of 18 and 40 years who have a normal weight (BMI 27), who are overweight (BMI \> 27), or who are overweight (BMI \> 27) and have non insulin-dependent diabetes. Design: * Arm 1: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Participants will take 500 1,000 mg of vitamin C twice daily for 2 weeks before admission to the clinical center for 1 week. * Study 1: Participants will eat breakfast containing a known amount of fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Other foods contain only negligible amounts of vitamin E. Blood and urine samples will measure levels of vitamin E and other substances. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of fat in the breakfast will range from 0% to 40% in random order. During one of the studies, an adipose tissue biopsy will be collected to determine how much vitamin E is in the tissues. * Arm 2: Five studies, each lasting 1 month with 1 month off between studies (total study = 10 months). Preparation for Arm 2 is the same as in Arm 1. The proportion of fat, muscle, and water in the body will also be measured. * Study 1: Participants will eat breakfast containing 30% fat, after which they will take a vitamin E pill as well as receive an IV injection of vitamin E. Conditions and procedures are the same as in Arm 1. * Studies 2 5: Outpatient visits will consist of the same tests as in Study 1; however, the amount of vitamin E in the breakfast will range from 2 to 30 mg in random order. * Arm 3: Outpatient (2 to 6 weeks) and inpatient studies (4 to 6 weeks). * Outpatient study: Participants will take 500 1,000 mg of vitamin C daily and provide blood and urine samples, as well as an adipose tissue sample. * Inpatient studies: Two vitamin E inpatient studies. Before these begin, participants vitamin C blood levels will be reduced by means of a diet low in vitamin C. Blood tests will determine how quickly vitamin C leaves the body. Once the vitamin C level is reduced, the first vitamin E study will begin. Study A: The procedure for this study is the same as in Arm 2, Study 1. Study B: The procedure for this study is the same as in Study A, except that the participants blood vitamin C levels will be higher. ...

Timeline

Start

2014-10-10

Primary completion

2016-10-21

Completion

2022-05-03

Publications

• Background Traber MG, Ramakrishnan R, Kayden HJ. Human plasma vitamin E kinetics demonstrate rapid recycling of plasma RRR-alpha-tocopherol. Proc Natl Acad Sci U S A. 1994 Oct 11;91(21):10005-8. doi: 10.1073/pnas.91.21.10005.
• Background Sowell J, Frei B, Stevens JF. Vitamin C conjugates of genotoxic lipid peroxidation products: structural characterization and detection in human plasma. Proc Natl Acad Sci U S A. 2004 Dec 28;101(52):17964-9. doi: 10.1073/pnas.0408433102. Epub 2004 Dec 17.
• Background Bruno RS, Ramakrishnan R, Montine TJ, Bray TM, Traber MG. alpha-Tocopherol disappearance is faster in cigarette smokers and is inversely related to their ascorbic acid status. Am J Clin Nutr. 2005 Jan;81(1):95-103. doi: 10.1093/ajcn/81.1.95.
• Traber MG, Leonard SW, Ebenuwa I, Violet PC, Niyyati M, Padayatty S, Smith S, Bobe G, Levine M. Vitamin E catabolism in women, as modulated by food and by fat, studied using 2 deuterium-labeled alpha-tocopherols in a 3-phase, nonrandomized crossover study. Am J Clin Nutr. 2021 Jan 4;113(1):92-103. doi: 10.1093/ajcn/nqaa298.
• Violet PC, Ebenuwa IC, Wang Y, Niyyati M, Padayatty SJ, Head B, Wilkins K, Chung S, Thakur V, Ulatowski L, Atkinson J, Ghelfi M, Smith S, Tu H, Bobe G, Liu CY, Herion DW, Shamburek RD, Manor D, Traber MG, Levine M. Vitamin E sequestration by liver fat in humans. JCI Insight. 2020 Jan 16;5(1):e133309. doi: 10.1172/jci.insight.133309.
• Traber MG, Leonard SW, Ebenuwa I, Violet PC, Wang Y, Niyyati M, Padayatty S, Tu H, Courville A, Bernstein S, Choi J, Shamburek R, Smith S, Head B, Bobe G, Ramakrishnan R, Levine M. Vitamin E absorption and kinetics in healthy women, as modulated by food and by fat, studied using 2 deuterium-labeled alpha-tocopherols in a 3-phase crossover design. Am J Clin Nutr. 2019 Nov 1;110(5):1148-1167. doi: 10.1093/ajcn/nqz172.

Drugs

Indications