Iron-fortified lentils to improve iron (Fe) status among adolescent girls in Bangladesh - study protocol for a double-blind community-based randomized controlled trial

BACKGROUND: Lentils are generally considered to be a nutrient-dense food, and a good source of iron (Fe). This study aims to establish novel evidence of the effectiveness of the consumption of Fe-fortified lentils in improving the body Fe status and thus cognitive performance in non-pregnant adolescent girls in rural Bangladesh, compared to consumption of ordinary lentils. METHODS: We have designed a double-blind (both trial participants and outcome assessors), community-based, cluster-randomized controlled trial among 1260 Bangladeshi adolescent girls between the ages of 10–17 years who are non-smoking, not married, not pregnant, not breastfeeding, and generally healthy at the time of enrollment. The intervention will include three arms who will receive: (1) Fe-fortified lentils; (2) unfortified lentils; or (3) usual intake. Participants will be served a thick preparation of cooked Fe-fortified lentils (37.5 g raw lentils, approximately 200 g cooked lentils) 5 days per week for 85 feeding days (around 4 months) using a locally acceptable recipe. Lentils were fortified with Fe in the laboratory at the Department of Plant Sciences at the University of Saskatchewan in Canada. A subsample of participants (n = 360) will be randomly invited to be included in cognitive testing. DISCUSSION: Data on socio-demographic characteristics, household food security status, adolescent food habits and cognitive testing will be collected at baseline and endline (4 months). Venous blood samples will be collected at baseline, midline (2 months) and endline to measure adolescents’ Fe status. Computerized cognitive testing will include five common measures of attentional (three of attention) and mnemonic functioning (two of memory) carried out using DMDX software. The results of this study will be used to garner support for and to substantiate large-scale production and market expansion of Fe-fortified lentils, and will contribute to knowledge about how to enhance Fe status in adolescents worldwide in resource-poor settings, using staple food crops. TRIAL REGISTRATION: ClinicalTrials.gov NCT03516734. Registered on 24 May 2018. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13063-019-3309-4) contains supplementary material, which is available to authorized users.