Systematic review and meta-analysis of iodine nutrition in modern vegan and vegetarian diets

Abstract

Vegan and vegetarian diets are widely supported and adopted, but individuals following such diets remain at greater risk of iodine deficiency. This systematic review and meta-analysis was conducted to assess the iodine intake and status in adults following a vegan or vegetarian diet in the modern day. A systematic review and quality assessment were conducted from October 2020-December 2022 according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidance. Studies were identified in Ovid MEDLINE, Web of Science, PubMed, and Scopus. Eleven articles were eligible for review containing 4,421 adults (aged ≥ 18 years). Vegan groups had the lowest median urinary iodine concentration (mUIC) (12.2 L−1). None of the dietary groups had mUIC within the optimal range for iodine status (100-200 µg L−1) (World Health Organisation). Vegan diets had the poorest iodine intake (17.3 µg day−1) and were strongly associated with lower iodine intake (P = < 0.001) compared to omnivorous diets. Lower intake in vegan diets were influenced by gender (P = 0.007), the presence of voluntary or absence of Universal Salt Iodisation (USI) programmes (P = 0.01 & P = < 0.001), and living in a country with adequate iodine nutrition (P = < 0.001). Vegetarians and particularly vegans, living in countries with no current USI programme continue to have increased risk of low iodine status, iodine deficiency and inadequate iodine intake. Further research into the usefulness of mandatory fortification of vegan appropriate foods is required.

Der Status von Spurenelementen bei veganer Ernährung

“…[11] Bezüglich des Status zeigten die meisten Studien erwartungsgemäß, dass Veganerinnen und Veganer eine deutlich schlechtere Jodversorgung aufwiesen als Mischköstlerinnen und Mischköstler. [8,9] Die Ergebnisse unserer RBVD Studie stimmten auch hier mit den Erkenntnissen aus den bisherigen Übersichtsarbeiten überein. [6] Zinkversorgung Zink ist ein weiteres Spurenelement, das aufgrund seines überwiegenden Vorkommens in tierischen Produkten als kritisch bei einer veganen Ernährung gesehen wird.…”

“Climate-friendly” diets from an allergy point of view

“…The only exception in this respect are calcium-fortified soy products [ 27 , 28 , 29 ]. The iodine supply is also at risk on the basis of the PHD [ 21 , 30 , 31 ]. As long as milk is not replaced by plant-based drinks, 85% of the adult recommendations can be provided with the PHD, but only 51 – 64% of those in pregnancy [ 30 ].…”

Genetics of vegetarianism: A genome-wide association study

“…While religious and ethical considerations were, and to a large extent still are, major motivations behind adopting a vegetarian diet, recent research has provided evidence for its health benefits, including lower risk of metabolic syndrome, obesity, dyslipidemias, diabetes, cardiovascular disease, and some cancers [5,6,[8][9][10][11][12][13][14][15]. On the other hand, there is evidence that vegetarian diets can lead to nutritional deficiencies and may be associated with negative effects such as anemia, dental erosion, osteopenia, and psychological disorders [16][17][18][19][20][21][22][23][24][25][26][27][28][29].…”