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

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

Assessing the prevalence and potential drivers of food insecurity and the relationship with mental wellbeing in UK university students: A cross-sectional study

Food insecurity (FI) among university students in the United States has been associated with poor mental wellbeing, but very little is known about the rela-tionship between FI and mental wellbeing in the UK university population. Here we examined the prevalence of FI, determined potential drivers for it and its relationship with mental wellbeing and coping ability. Students studying at UK universities (n= 289) completed an online self-reported questionnaire to obtain socio-economic characteristics including financial status, FI status (Household Food Insecurity Access scale), mental wellbeing (Warwick-Edinburgh Mental Wellbeing Scale) and coping ability (coping flexibility scale). FI was observed in 28% of the participants and was associated with financial independence, run-ning out of money, borrowing money and lacking confidence to purchase healthy foods (p< 0.05). Although we cannot determine directionality, logistic regression analysis revealed those who were judged as FI were more likely to shop often (OR= 3.139 95% CI 1.533–6.429), never snacked between meals (OR = 4.261 95% CI 1.309–13.875) and the amount of food purchased was affected by perceptions of the price of food in general (OR = 2.954 95% CI 1.675–5.210). Financial instability and the inability to access nutritious food may contribute to the decrease in mental wellbeing (p< 0.01) and lower ability to cope with stress-ful situations (p< 0.01) in food-insecure students although the direction of these relationships cannot be determined from this cross-sectional study. This study has identified that there is a need to develop appropriate strategies to combat FI in university students and to improve mental health

Trace Mineral Intake and Deficiencies in Older Adults Living in the Community and Institutions: A Systematic Review

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. The global population is ageing with many older adults suffering from age-related malnutrition, including micronutrient deficiencies. Adequate nutrient intake is vital to enable older adults to continue living independently and delay their institutionalisation, as well as to prevent deterioration of health status in those living in institutions. This systematic review investigated the insufficiency of trace minerals in older adults living independently and in institutions. We examined 28 studies following a cross-sectional or cohort design, including 7203 older adults (≥60) living independently in 13 Western countries and 2036 living in institutions in seven Western countries. The estimated average requirement (EAR) cut-off point method was used to calculate percentage insufficiency for eight trace minerals using extracted mean and standard deviation values. Zinc deficiency was observed in 31% of community-based women and 49% of men. This was higher for those in institutional care (50% and 66%, respectively). Selenium intakes were similarly compromised with deficiency in 49% women and 37% men in the community and 44% women and 27% men in institutions. We additionally found significant proportions of both populations showing insufficiency for iron, iodine and copper. This paper identifies consistent nutritional insufficiency for selenium, zinc, iodine and copper in older adults

Geographical and seasonal variation in Iodine content of cow’s milk in the UK and consequences for the consumer´s supply

Background. Dairy products provide a crucial source of dietary iodine for the majority of the UK population, contributing approximately 30-40 % of daily intake. Fluctuations in the iodine content of purchased milk both seasonally and annually implies potential fragility of iodine supply likely through fluctuating supplementation practices in cow herds. We set out to establish the level of national variation in herds and identify factors which might impact milk iodine content. Methods. Milk samples were obtained from 98 herds across the UK via the National Milk Laboratories in August and December 2016. Iodine concentration of samples was measured using ICP-MS. Milk samples and feed intake data were additionally taken from 22 cows from the University of Nottingham (UON) dairy herd. Results. There was considerable variation in milk iodine content from < 0.012 (Limit of Detection) to 1558 µg L-1, with a summer median of 197 µg L-1 and winter median 297 µg L-1. Overall, winter values were higher than summer counterparts (

Genetic and Non-Genetic Influences during Pregnancy on Infant Global and Site Specific DNA Methylation: Role for Folate Gene Variants and Vitamin B12

Inter-individual variation in patterns of DNA methylation at birth can be explained by the influence of environmental, genetic and stochastic factors. This study investigates the genetic and non-genetic determinants of variation in DNA methylation in human infants. Given its central role in provision of methyl groups for DNA methylation, this study focuses on aspects of folate metabolism. Global (LUMA) and gene specific (IGF2, ZNT5, IGFBP3) DNA methylation were quantified in 430 infants by Pyrosequencing®. Seven polymorphisms in 6 genes (MTHFR, MTRR, FOLH1, CβS, RFC1, SHMT) involved in folate absorption and metabolism were analysed in DNA from both infants and mothers. Red blood cell folate and serum vitamin B12 concentrations were measured as indices of vitamin status. Relationships between DNA methylation patterns and several covariates viz. sex, gestation length, maternal and infant red cell folate, maternal and infant serum vitamin B12, maternal age, smoking and genotype were tested. Length of gestation correlated positively with IGF2 methylation (rho = 0.11, p = 0.032) and inversely with ZNT5 methylation (rho = −0.13, p = 0.017). Methylation of the IGFBP3 locus correlated inversely with infant vitamin B12 concentration (rho = −0.16, p = 0.007), whilst global DNA methylation correlated inversely with maternal vitamin B12 concentrations (rho = 0.18, p = 0.044). Analysis of common genetic variants in folate pathway genes highlighted several associations including infant MTRR 66G>A genotype with DNA methylation (χ2 = 8.82, p = 0.003) and maternal MTHFR 677C>T genotype with IGF2 methylation (χ2 = 2.77, p = 0.006). These data support the hypothesis that both environmental and genetic factors involved in one-carbon metabolism influence DNA methylation in infants. Specifically, the findings highlight the importance of vitamin B12 status, infant MTRR genotype and maternal MTHFR genotype, all of which may influence the supply of methyl groups for DNA methylation. In addition, gestational length appears to be an important determinant of infant DNA methylation patterns

Baseline characteristics of the study population.

†<p>Mothers' red cell folate and B₁₂ concentrations were measured from routine antenatal blood samples (mean (SD) gestation = 10.6 (4.3) weeks).</p

Associations between methylation and genetic predictors.

†<p>Associations between methylation and SNP genotypes were tested initially under a genotypic model using a non-parametric Kruskal-Wallis Test, unless otherwise stated. Those showing association were tested further under dominant/recessive and additive models using Kruskal-Wallis and Trend tests, respectively.</p>‡<p>Test statistics and p-values from the most appropriate model are presented.</p>Φ<p>SNP <i>GCPII/FOLHI</i> 1561C>T and <i>CβS</i> 644ins were tested under a dominant model (with respect to the minor allele) only due to their low MAF (i.e. 5–15%). *A higher methylation ratio is indicative of less methylated DNA.</p

Associations between methylation and non-genetic predictors.

†<p>Non-parametric Kruskal-Wallis test for association was performed between methylation and categorical predictor variables. Spearman's rank correlation was assessed between methylation and continuous predictor variables.</p>*<p>A higher methylation ratio is indicative of less methylated DNA therefore the positive correlation reported shows that a higher maternal serum B₁₂ level is associated with lower genomic DNA methylation.</p

Univariate and multiple linear regression analysis.

*<p>Dominant models were applied for these SNPs, hence coefficients reflect the difference in methylation level for carriers of the minor allele compared to major allele homozgyotes (reference group).</p>†<p>Females were compared to males (reference group).</p>‡<p>Additive models were applied for these SNPs, hence coefficients reflect the difference in methylation level for each additional copy of the minor allele compared to major allele homozygotes (reference group).</p>Φ<p>Recessive models were applied for these SNPs, hence coefficients reflect the difference in methylation level for minor allele homozygotes compared to carriers of the major allele (reference group).</p>ł<p>Reduced numbers in multiple regression models are due to limited maternal genotype data and removal of outliers, consequently, these reduced numbers may in part account for the lack of significance seen with some predictor variables. Note also that mean methylation levels were utilized for multiple regression modelling despite not always demonstrating the strongest effect size with individual predictors. Standardised beta coefficients are obtained by first standardizing all variables to have a mean of 0 and a standard deviation of 1, they denote the increase in methylation for a standard deviation increase in the predictor variables. Multiple regression analysis was not performed for ZNT5 associations as mean methylation was not considered across this locus.</p