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Vegans, Vegetarians, and Omnivores: How Does Dietary Choice Influence Iodine Intake? A Systematic Review

Eveleigh, Elizabeth; Coneyworth, Lisa J.; Avery, Amanda; Welham, Simon J.M.


Elizabeth Eveleigh

Lisa J. Coneyworth

Amanda Avery

Simon J.M. Welham


Vegan and vegetarian diets are becoming increasingly popular. Dietary restrictions may increase the risk of iodine deficiency. This systematic review aims to assess iodine intake and status in adults following a vegan or vegetarian diet in industrialised countries. A systematic review and quality assessment were conducted in the period May 2019-April 2020 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies were identified in Ovid MEDLINE, Embase, Web of Science, PubMed, Scopus, and secondary sources. Fifteen articles met inclusion criteria. Participants included 127,094 adults (aged ≥ 18 years). Vegan groups presented the lowest median urinary iodine concentrations, followed by vegetarians, and did not achieve optimal status. The highest iodine intakes were recorded in female vegans (1448.0 ± 3879.0 µg day-1) and the lowest in vegetarians (15.6 ± 21.0 µg day-1). Omnivores recorded the greatest intake in 83% of studies. Seaweed contributed largely to diets of vegans with excessive iodine intake. Vegans appear to have increased risk of low iodine status, deficiency and inadequate intake compared with adults following less restrictive diets. Adults following vegan and vegetarian diets living in countries with a high prevalence of deficiency may be more vulnerable. Therefore, further monitoring of iodine status in industrialised countries and research into improving the iodine intake and status of adults following vegan and vegetarian diets is required.

Journal Article Type Article
Publication Date May 29, 2020
Journal Nutrients
Electronic ISSN 2072-6643
Publisher MDPI
Peer Reviewed Peer Reviewed
Volume 12
Issue 6
Article Number 1606
APA6 Citation Eveleigh, E., Coneyworth, L. J., Avery, A., & Welham, S. J. (2020). Vegans, Vegetarians, and Omnivores: How Does Dietary Choice Influence Iodine Intake? A Systematic Review. Nutrients, 12(6),
Keywords Iodine status; Iodine intake; Iodine deficiency; Vegan; Vegetarian
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REVISED22.05.20V2 How Does Dietary Choice Influence Iodine Intake Manuscript (681 Kb)

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