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

Nutrients

Jan 2022

DOI: 10.3390/nu14030535

Citations:32

Influential Citations:3

Observational Studies (Human)

Enhanced Details

Methods

Cross-sectional observational study in the Czech Republic. Participants: 200 children categorized as vegetarian (VG, n=79), vegan (VN, n=69), or omnivore controls (OM, n=52), aged 0–18 years. Recruited between November 2019 and July 2021. Inclusion: self/parent-reported VG/VN/OM and age 0–18 years. Exclusion: chronic diseases affecting absorption (e.g., enteropathy, pancreatic insufficiency, metabolic disorders). Data collection included fasting blood samples for holotranscobalamin (active B12), cyanocobalamin, folate, homocysteine, mean corpuscular volume, and hemoglobin; 3-day weighed dietary records; anthropometrics. Statistical analyses included ANOVA or Kruskal–Wallis for continuous variables, Fisher’s exact test for categorical variables, and multivariable logistic regression adjusted for age and sex. Subgroup analysis examined breastfed infants 0–3 years. Ethics approvals obtained and informed consent collected.

Intervention

Vitamin B12 supplementation regimens observed in Czech VG (vegetarian) and VN (vegan) children and their mothers. Children used multiple chemical forms of B12 (methylcobalamin, cyanocobalamin, adenosylcobalamin, hydroxymethylcobalamin) delivered as drops or pills. Per-dose medians: 86.5 µg (IQR 250.0) for VG; 98.6 µg (IQR 210.0) for VN. Mean per-dose: 178.9 ± 238.5 µg (VG); 278.35 ± 394.63 µg (VN). Frequency categories: everyday (VG 37; VN 44), irregular (VG 2; VN 2), once a week (VG 6; VN 2), twice a week (VG 7; VN 3), three times a week (VG 2; VN 8); Non-supplementing: VG 25; VN 10. Chemical forms among supplementing participants: methylcobalamin (VG 23; VN 35), cyanocobalamin (VG 30; VN 21), adenosylcobalamin (VG 1; VN 1), hydroxymethylcobalamin (VG 0; VN 2). Medical form: drops (VG 28; VN 33), pills (VG 26; VN 26); Non-supplementing medical form: 25 (VG) and 10 (VN). For mothers during pregnancy and lactation: 78.3% supplemented during both; 13.0% only during breastfeeding; 2.2% only during pregnancy; 6.5% none. Duration of supplementation not reported for either children or mothers. Dietary intake data: dietary B12 from diet alone was 0 µg/day in vegans; vegetarians not restricted to dairy/eggs had about 1.9 µg/day with supplementation (p<0.001).

Results

Key findings: supplementation differs between VG and VN (p=0.019). There was a statistically significant difference in B12 levels across diet groups, with omnivores showing the lowest B12 measures (B12 [µg/L]: VG ≈ 572, VN ≈ 546, OM ≈ 433; aB12 (holotranscobalamin) did not differ significantly (p=0.257). Vitamin B12 hypervitaminosis was common in VG/VN/OM, with n=35 VG, n=28 VN, and n=9 OM meeting laboratory criteria (p=0.004), indicating over-supplementation in some children. Lab-defined B12 deficiency was rare (n=3 across groups). Among breastfed children aged 0–3 years (n=46), 78.3% of mothers supplemented during both pregnancy and lactation; 28.3% of the selected children were supplemented; of non-supplemented children, some achieved adequate saturation if their mothers were adequately supplemented; only 1 child not supplemented showed deficiency, and some cases occurred when maternal supplementation was high-dose but the child was not supplemented. Authors conclude that Czech VG/VN children may be at risk of cobalamin deficiency when not adequately supplemented, but no life-threatening deficiency was observed; there is a notable occurrence of hypervitaminosis with unknown health impact. They advocate using holotranscobalamin as a primary screening marker, developing pediatric B12 supplementation guidelines for VG/VN diets, and ensuring maternal supplementation during pregnancy/lactation to protect offspring who are not supplemented.

Limitations

Cross-sectional design limits causality; potential selection bias due to recruitment via general practitioners and social networks; subgroup sizes (infants/toddlers and schoolers) are limited; reliance on self-reported supplement use and 3-day dietary records may introduce reporting bias; did not measure methylmalonic acid (MMA); no data on long-term outcomes of hypervitaminosis B12; pregnant/lactating individuals were not included, limiting generalizability to those populations.

Abstract

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. show less