Table 3.
Studies investigating iodine among vegans, vegetarians and omnivores published after January 2020
| Study, year | Study design | Location | Dietary groups | Sample | Method of dietary classification | Grouping adherence length | ||
|---|---|---|---|---|---|---|---|---|
| N | Female, male | |||||||
| Abraham et al. 2022(53) | Cross-sectional | Berlin, Germany | Strict raw | 16 | 5, 11 | Classified according to RBVD study criteria. (not self-selected) | Diet for at least four months or at least one year | Raw food diet |
| Vegan | 32 | 18, 14 | ||||||
| Omnivore | 27 | 14, 13 | ||||||
| Blaurock et al. 2021(54) | Cross-sectional | Munich, Germany | Vegetarian | 31 | 31, 0 | Self-assessed | NA | |
| Omnivore | 30 | 30, 0 | ||||||
| Dawczynski et al. 2022(49) | Cross-sectional | Jena, Halle, and Leipzig, Germany | Vegan | 58 | 41, 17 | Self-assessed. Food intake data were also checked by researchers for discrepancies in diet selection | 3·0 | 3·0* |
| Vegetarian (lacto-ovo) | 65 | 47, 18 | 6·0 | 10.* | ||||
| Flexitarian | 70 | 56, 14 | 8·0 | 17·8* | ||||
| Omnivore | 65 | 40, 25 | 32·0 | 20·0* | ||||
| Eveleigh et al. 2022(34) | Cross-sectional | Nottingham, UK | Vegan (2016–17) | 12 | 12, 0 | Self-assessed. Food intake data were also checked by researchers for discrepancies in diet selection | > 6 months | |
| Vegan (2019) | 7 | 4,3 | ||||||
| Vegetarian (including pescatarians) (2016–17) | 5 | 5, 0 | ||||||
| Vegetarian (including pescatarians) (2019) | 10 | 9, 1 | ||||||
| Omnivore (2016–17) | 43 | 36, 7 | ||||||
| Omnivore (2019) | 19 | 14, 5 | ||||||
| Fallon and Dillon, 2020(33) | Cross-sectional | Lancashire, UK | Vegan | 20 | 20, 0 | The diaries were cross-checked to ensure they had correctly identified themselves | NA | |
| Vegetarian | 16 | 16, 0 | ||||||
| Omnivore | 26 | 26, 0 | ||||||
| García-Morant et al. 2020(55) | Cross-sectional | Spain | Vegan | 102 | 67, 35 | NA | NA | |
| Omnivore | 3323 | 1732, 1587 | ||||||
| Groufh-Jacobsen et al. 2020(50) | Cross-sectional | Oslo, Norway | Vegan | 115 | 74, 41 | Classified by researchers according to questions addressing animal product consumption | ≥ 6 months | |
| Vegetarian | 55 | 43, 12 | ||||||
| Pescatarian | 35 | 31, 4 | ||||||
| Jakše et al. 2021(56) | Cross-sectional | Slovenia | Vegan | 51 | 34, 17 | Self-assessed. Food intake data were also checked by researchers for discrepancies in diet | Participants should have had the same (current) dietary pattern for ≥ 1 year | |
| Omnivore (non-vegan) | 29 | 16, 13 | ||||||
| Kowalska et al. 2020(57) | Data modelling | Poland | Vegan | Participants were only used for creation of the Omnivore (regular) diet. The other diets were generated by quantitative analysis of a total of 70 menus (10 for each diet type) prepared by dieticians | NA | NA | ||
| Vegetarian (lacto-ovo) | ||||||||
| Pescatarian | ||||||||
| Omnivore (fish free) | ||||||||
| Omnivore (milk free) | ||||||||
| Omnivore (basic) | ||||||||
| Omnivore (regular) | 30 | 12, 18 | ||||||
| Menzel et al. 2021(51) | Matched pairs (age and sex) | Germany | Vegan | 36 | 18,18 | Self-assessed | 4·8 | 3·1–8·7* |
| Omnivore | 36 | 18,18 | ||||||
| Whitbread et al. 2021(52) | Cross-sectional | South Australia | Vegan | 31 | 31, 0 | Self-assessed | NA | |
| Omnivore | 26 | 26, 0 | ||||||
NA, not assessed.
*
Median and IQR.