RESEARCH Research and Practice Innovations A Novel Dietary Intervention to Optimize Vitamin E Intake of Pregnant Women to 15 mg/ Day JULIA CLARK, MSc; LEONE CRAIG, PhD; GERALDINE McNEILL, PhD, MB ChB,* MSc; NORMAN SMITH, MD, FRCOG; JOHN NORRIE, MSc; GRAHAM DEVEREUX, MD, PhD ABSTRACT Associations have been reported between suboptimal ma- ternal vitamin E intake during pregnancy and childhood asthma. This pilot study conducted in 2008/2009 investi- gated the feasibility and acceptability of a food-based randomized controlled trial in pregnant women to opti- mize dietary vitamin E intake to 15 mg/day. A food-based intervention using “food exchanges” to individually opti- mize dietary vitamin E intake to 15 mg/day was devel- oped and included in an advice booklet. Forty-three preg- nant women with a personal/partner history of asthma were recruited at 12 weeks gestation and randomized to food-based intervention or a control group until 20 weeks gestation. A registered dietitian assessed the vitamin E intake of 22 women and provided tailored advice on food- based exchanges to optimize their intake to 15 mg/day. The 21 control women were not given dietary advice. The food-based intervention was completed by 19 women and increased mean vitamin E intake: food diary data, 7.13 mg/day (95% confidence interval: 5.63 to 18.6) to 17.4 mg/day (95% confidence interval: 14.4 to 20.5) (P0.001). This pilot study demonstrates the feasibility and accept- ability of a food-exchange-based intervention to optimize dietary vitamin E intake during pregnancy. Additional work is required to determine whether this intervention, if sustained for the rest of pregnancy, reduces the likeli- hood of childhood asthma. The methodology used in the design of this novel food-based intervention could be transferred to other nutrients. J Acad Nutr Diet. 2012;112:297-301. I t has been hypothesized that changes in diet have contributed to the recent marked increase in asthma (1,2), with a recent systematic review concluding that there is strong supportive evidence to prioritize trials of increasing maternal vitamin E intake during pregnancy as a potential population-based intervention to reduce childhood asthma (3). This article describes the develop- ment of a novel food-based intervention to optimize ma- ternal vitamin E intake during pregnancy to 15 mg/day and the results of piloting the intervention in a short- term randomized controlled trial. The possibility of conducting a trial of vitamin E mod- ification in pregnancy in relation to childhood asthma is being considered. Several considerations support the no- tion of using a food-based intervention to optimize mater- nal vitamin E intake to 15 mg/day in preference to vita- min E supplementation. Firstly, previous antioxidant supplementation trials have failed to demonstrate bene- ficial effects on cardiovascular disease, cancer, and all- cause mortality, despite reports of beneficial associations from observational studies (4). Recently, a pre-eclampsia trial of vitamin E supplementation during pregnancy re- ported that supplements of vitamin E (133 mg/day) dur- ing pregnancy did not reduce the incidence of respiratory outcomes in children up to 2 years (5). These studies suggest that supplements of maternal vitamin E during pregnancy are unlikely to have a beneficial effect on childhood asthma. Secondly, the use of a food-based in- tervention to enhance a dietary pattern that increases vitamin E intake embraces the complexity of diet by pragmatically accepting that the intervention not only increases vitamin E intake, but also the intake of natu- rally associated nutrients. A strength of such an inter- vention is that other nutrients (eg, polyunsaturated fatty acid [PUFA], vitamin D), or the nutrient composition of the overall dietary pattern, can be essential for any ben- eficial effect. Finally, although in the United Kingdom there are no explicit recommendations for vitamin E in- take, the US recommended daily allowance for women is 15 mg/day, and is unchanged by pregnancy (6). Because of the innovative nature of such a food-based intervention, it was considered necessary to pilot the J. Clark is a research dietitian and L. Craig is a re- search fellow, Public Health Nutrition Research Group, G. McNeill is a professor of public health nutrition, and G. Devereux is a professor of respiratory medicine and an honorary consultant physician, all at the University of Aberdeen, Aberdeen, UK. N. Smith is a consultant obstetrician, Aberdeen Maternity Hospital, Aberdeen, UK. J. Norrie is a professor of clinical trials and biosta- tistics, University of Glasgow, Glasgow, UK. *MB ChB are the minimal professional clinical quali- fications required in the UK; Bachelor of Medicine (MB), Bachelor of Surgery (ChB), are equivalent to the US MD. Address correspondence to: Julia Clark, MSc, Public Health Nutrition Research Group, Health Sciences Building, First Floor, University of Aberdeen, Aberdeen AB25 2ZD, UK. E-mail: j.clark@abdn.ac.uk Manuscript accepted: July 19, 2011. Copyright © 2012 by the Academy of Nutrition and Dietetics. 2212-2672/$36.00 doi: 10.1016/j.jada.2011.08.033 © 2012 by the Academy of Nutrition and Dietetics Journal of the ACADEMY OF NUTRITION AND DIETETICS 297