Health aspects of vegan diets among children and adolescents: a systematic review and meta-analyses.

Health effects of vegan diets among children and adolescents are a controversial public health topic. Thus, the aim of the present systematic review is to evaluate a broad range of health outcomes among vegan children and adolescents aged 0 to 18 years. 18 studies met the inclusion criteria (17 cross-sectional, 1 RCT). Meta-analyses showed lower protein, calcium, vitamin B2, saturated fatty acid, and cholesterol intakes, and lower ferritin, HDL and LDL levels as well as height in vegan compared to omnivorous children/adolescents. Higher intakes of carbohydrates, polyunsaturated fatty acids, fiber, folate, vitamins C and E, magnesium, iron, and potassium were observed in vegans. Blood levels of vitamin B12 were higher among vegan children due to supplement use. Single study results suggested further differences between vegan and non-vegan children, such as lower bone mineral content or urinary iodine among vegan children. Risk of Bias was rated as high or very high in 7 out of 18 studies. The certainty of evidence for the meta-analyses was low (n = 2) or very low (n = 46). Overall, the available evidence points to both risks and benefits associated with a vegan diet among children, although more and better designed studies are needed.

Prevalence of iodine deficiency among vegan compared to vegetarian and omnivore children in the Czech Republic: cross-sectional study.

BACKGROUND: The intake and homeostasis of iodine, an essential micronutrient that plays a vital role in thyroid physiology, is of particular concern with the increasing popularity of vegetarian (VG) and vegan (VN) diets. Children on these restrictive diets may be at risk of possible adverse effects on growth and development, but there is currently a lack of recent epidemiological studies on this topic. METHODS: We gathered clinical, anthropometric, and blood/urine data on iodine status and thyroid function from children aged 0-18 years who followed either a VG diet (n = 91), VN diet (n = 75), or omnivore diet (OM, n = 52). Cross-sectional comparison of the groups and linear regression was used. Stratified analyses were performed based on age (according to WHO): 0-5 years and 6-18 years. RESULTS: Our study revealed no significant differences in levels of thyroid-stimulating hormone (TSH), triiodothyronine (fT3), thyroglobulin (TG) or anti-thyroid peroxidase antibody (ATPOc) between the VG, VN, and OM groups. However, thyroxine (fT4) levels were found to be higher in the VN group compared to the OM group (15.00 ± 1.73 vs. 16.17 ± 1.82 pmol/l, p < 0.001). The presence of anti-thyroglobulin antibodies (AhTGc) was notably more common in the VG (18.2%)/VN (35.0%) groups than in the OM group (2.1%) (p < 0.001). Regarding iodine status, the concentration of iodine in spot urine (UIC) was found to be highest in the OM group (197.28 ± 105.35 vs. VG: 177.95 ± 155.88 vs. VN: 162.97 ± 164.51 µg/l, p < 0.001). Notably, the lowest (5.99 µg/l) and highest (991.80 µg/l) levels were measured in the VN group. Of the participants, 31 VN, 31 VG and 10 OM children met the criteria for iodine deficiency (i.e., UIC < 100 µg/l). We found that children with regular iodine supplementation had higher UIC (p < 0.001). Importantly, the median UIC was above 100 µg/l in all three groups, through the recommended intake (RDI) of iodine was rarely met throughout the groups. CONCLUSION: We have observed a trend to lower UIC values in VN as compared to OM. This trend is also reflected in the median UIC values, even though the median UIC values were above the WHO cut-off (e.g., 100 µg/l) for iodine deficiency in all dietary groups. These results suggest that VN and VG children may be more at higher risk of iodine deficiency, this theory is also supported by higher prevalence of AhTGc positivity. Further research is needed to investigate the long-term impact of these dietary patterns on iodine status and thyroid function in children. Given our findings, it may also be necessary to consider new guidelines for supplementing children following VG and VN diets to ensure their iodine needs are met.

Cross sectional study of vitamin B12 supplementation in Slovak and Czech vegans.

Background: The number of vegans in the world is growing and in Slovakia and the Czech Republic they make up 1% of the population. Vegan diet excludes all foods of animal origin and vegans who do not use vitamin B12 supplements are at risk of the vitamin B12 deficiency. Objective: The aim of this study was to determine what proportion of Czech and Slovak vegans use vitamin B12 supplements regularly, irregularly or not at all and what is their supplemental cobalamin intake. Materials and methods: The research involved 1337 self-identified vegans from Slovakia and the Czech Republic who were interviewed using the CAWI (Computer-Assisted Web Interview) method. Participants were recruited by posts in veganism-themed social media groups. Results: Out of 1337 vegans 55.5% supplemented cobalamin regularly, 32.54% irregularly and 11.97% were not supplementing. Rate of not supplementing individuals was 5.04% higher in Slovaks than in Czechs. Short-term vegans had a significantly higher rate of not supplementing individuals (17.99%) compared to medium-term (8.37%) and long-term vegans (7.50%). Mean weekly cobalamin intake from supplements was 2938.34±2566.60 µg in regularly supplementing vegans compared to 1630.31±1949.27 µg in irregularly supplementing vegans, particularly due to the lower weekly supplementation frequency among irregularly (2.93) compared to regularly supplementing vegans (5.27). Conclusions: The rate of supplementation in Slovak and particularly Czech vegans was higher than in other countries. The number of not supplementing individuals was significantly higher among short-term vegans, indicating that there is still a need for education on the importance of adequate and regular cobalamin supplementation, especially in new vegans. Our results support the hypothesis that the reason for higher rate of cobalamin deficiency in irregularly compared to regularly supplementing vegans is the lower cobalamin intake caused by lower supplementation frequency.

Cross-Sectional Study of the Prevalence of Cobalamin Deficiency and Vitamin B12 Supplementation Habits among Vegetarian and Vegan Children in the Czech Republic.

Vegetarian (VG) and vegan (VN) diets in childhood are of growing interest due to their perceived health and environmental benefits. Concerns remain due to the possible disruption of healthy growth and development of children because of the scarcity of evidence-based studies. Among the nutrients of special concern is vitamin B12. Therefore, the Czech Vegan Children Study (CAROTS) decided to examine the relationship between B12 metabolism parameters and B12 intake through diet and supplementation. We analyzed laboratory parameters within n = 79 VG, n = 69 VN, and n = 52 omnivores (OM) children (0−18 years old). There were no significant differences in levels of holotranscobalamin (aB12), folate, homocysteine (hcys), or mean corpuscular volume. However, there was a significant difference in levels of cyanocobalamin (B12) (p = 0.018), even though we identified only n = 1 VG and n = 2 VN children as B12 deficient. On the other hand, we identified n = 35 VG, n = 28 VN, and n = 9 OM children with vitamin B12 hypervitaminosis (p = 0.004). This finding was related to a high prevalence of over-supplementation in the group (mean dose for VG 178.19 ± 238.5 µg per day; VN 278.35 ± 394.63 µg per day). Additionally, we found a significant (p < 0.05) difference between B12, aB12, and hcys levels of supplemented vs. non-supplemented VG/VN children. This can show that the intake of vitamin B12 via diet in the VG group might not be sufficient. Secondly, we analyzed a relation between supplement use in pregnancy and breastfeeding and its impact on vitamin B12 levels of children aged 0−3 years. Out of n = 46 mothers, only n = 3 (e.g., 6.5%) were not supplemented at all. We have not identified any clinical manifestation of B12 deficiency and only n = 1 child with low serum cobalamin, a child who did not receive vitamin B12 supplementation and whose mother took only low doses of vitamin B12 (25/µg/day).To conclude, we did not observe any life-threatening or severe consequences of laboratory-stated vitamin B12 deficiency; thus, our group was well supplemented. On the other hand, we have identified many subjects with vitamin B12 hypervitaminosis of unknown impact on their health. Further research and new guidelines for B12 supplementation among VG and VN children are needed.

Iodine-containing food supplements available on the Czech market.

Iodine deficiency can cause several serious disorders, which are referred to as iodine deficiency disorders. Consequences of iodine deficiency can be prevented, for example by increased dietary intake of iodine. In the diet, iodine is found mainly in sea fish, seafood and seaweed (kelp, kombu, nori, wakame), eggs and dairy products, but also in mineral waters. An important source of iodine is also table salt, which has been fortified in the Czech Republic, resp. Czechoslovakia since 1947; currently valid concentration 27±7 mg/kg dates from 1997. Iodine deficiency can be prevented or solved with the help of increasingly popular food supplements. To describe the range of supplements available on the Czech market, online investigation of retailers was carried out in the period from February to the end of March 2021. Approximately 91 different food supplements were found to have listed, which have iodine in their composition. These accessories are available in various forms. The price for the recommended daily dose ranges from 1 to about 30 CZK, exceptionally raises even to 60 CZK. Supplements were divided into 8 groups according to different specifications and suitability for use for certain groups in the population. The spectrum of available food supplements is rich and in their choice care should be taken in consulting doctor or pharmacist, as the content of the supplement may exceed a safe dose for long-term use.

Vitamin B12 Deficiency Is Prevalent Among Czech Vegans Who Do Not Use Vitamin B12 Supplements.

As not much is known about the prevalence and predictors of nutritional deficiencies among vegans in the Czech Republic, we evaluated whether supplement use and duration of adherence to the vegan diet are associated with the risk of cobalamin and iron deficiencies. Associations between self-reported supplementation and duration of vegan diet with biomarkers of cobalamin (serum cobalamin, holotranscobalamin, homocysteine, folate) and iron status (serum ferritin, iron binding capacity, transferrin and saturation of transferrin) were assessed by cross-sectional analyses of medical data from a clinical nutrition center. Data from 151 (72 females) adult vegans (age 18-67 years), who were free of major chronic diseases and 85 (40 females) healthy non-vegans (age 21-47 years) were analyzed. Overall, vegans had significantly lower cobalamin, hemoglobin and ferritin levels, but higher folate and MCV values compared to non-vegans. Vegans not using cobalamin supplements were at higher risk of low plasma cobalamin than regularly supplementing vegans (OR: 4.41, 95% CI 1.2-16.16 for cobalamin, OR: 19.18, 95% CI 1.02-359.42 for holotranscobalamin), whereas no significant differences in cobalamin status related to duration of the vegan diet were observed. Regularly supplementing vegans had similar levels of cobalamin/holotranscobalamin as non-vegans. Despite lower ferritin and hemoglobin levels, there was no indication of a higher risk of iron-deficiency among vegans. To conclude cobalamin deficiency risk depends on supplementation status and not on the duration of an exclusive vegan diet, which underlines the need to integrate cobalamin status monitoring and counselling on supplement use in routine clinical care in the Czech Republic.