Vitamin B-12 deficiency and malabsorption are highly prevalent in rural Mexican communities

Skeletal evidence of structural violence among undocumented migrants from Mexico and Central America

OBJECTIVES

We examine the prevalence and sociodemographic risk factors of skeletal indicators of stress in forensic samples of undocumented migrants from Mexico and Central America.

MATERIALS AND METHODS

Cranial and dental remains of 319 migrants recovered in the Arizona and Texas borderlands were assessed for porotic hyperostosis (PH), cribra orbitalia (CO), and linear enamel hypoplasias (LEH). Logistic regression models for each condition were estimated to test for associations with biological sex, age, recovery location, and whether individuals were identified. Additional models estimated for a subsample of identified migrants included region of origin, residential context, and community indigeneity.

RESULTS

The full sample shows moderate crude prevalence of CO (9.6%) and LEH (34.1%), and a high prevalence of PH (49.6%). Significantly higher odds of PH are associated with being male (2.16 times higher), unidentified (1.89 times higher), and recovered in Arizona (3.76 times higher). Among identified migrants, we fail to find associations significant at the p < 0.05 level between skeletal stress and all sociodemographic variables except age.

DISCUSSION

The factors associated with PH may be related to influences on decisions to migrate and diversity among migrant sending regions. The skeletal evidence for early life stress is generally consistent with common public health concerns among impoverished communities in the region. The lesions themselves are viewed as embodied risk of physiological disturbance when resource access is structured by higher-level social, economic, and political forces. Forensic anthropologists would benefit from increased sensitivity to embodied structural violence among the vulnerable individuals and communities they serve.

Low Serum B12 Concentrations Are Associated with Low B12 Dietary Intake But Not with Helicobacter pylori Infection or Abnormal Gastric Function in Rural Mexican Women

Background: Gastric function, Helicobacter pylori infection, and vitamin B12 (B12) dietary intake were assessed as predictors of serum B12. Methods: H. pylori antibodies, gastric function, B12 dietary intake, and biochemical/hematological parameters were measured in 191 adult women from two rural communities in Querétaro, Mexico. Results: The overall mean serum B12 concentration was 211 ± 117 pmol/L. The prevalences of low (≤ 148 pmol/L), marginal (148 to 221 pmol/L), and adequate (> 221 pmol/L) serum B12 were 28.4%, 31.1%, and 40.5%, respectively. Seventy-one percent of women tested positive for H. pylori antibodies. The prevalence of gastric function categories did not differ by serum B12 categories. The odds ratio for having low serum B12 was 2.7 (p = 0.01) for women with an intake below the estimated average requirement, 3.6 (p = 0.01) for those in the lowest tertile of total B12 intake, and 3.0 (p = 0.02) for those in the lowest tertile of B12 intake from animal source foods. Age and B12 intake were predictors of serum B12 concentrations [serum B12 (pmol/L) = 90.060 + 5.208 (B12 intake, µg/day) + 2.989 (age, years). Conclusions: Low serum B12 concentrations were associated with low B12 dietary intake but not with H. pylori infection or abnormal gastric function in rural Mexican women.

Prevalence of low serum vitamin B12 in Mexican children and women: results from the first National Nutrition Survey (1999) as a basis for interventions and progress

Serum samples from the 1999 Mexico National Nutrition Survey (NNS) were analyzed to determine the prevalence of low serum B12 concentrations, identify factors related with low values including B12 intake, and importantly, to provide a baseline for monitoring progress in reducing deficiency. Samples for B12 were available from 488 children and 464 women, a sub-sample of the nationally representative 1999 NNS. The national overall prevalence of low (<200 pg/mL) and marginal (200 to 300 pg/mL) serum B12 was 25.6% and 21.0%, respectively. Adolescent girls had the lowest serum B12 concentrations (325 ± 308 pg/mL) and the prevalence of deficiency was 40% in pregnant women even using a lower cut-point (<135 pg/mL). Residents of rural areas and the South, population groups with poorest socioeconomic status, and illiterate and indigenous women had the lowest serum B12 Children and women who met dietary recommendations for B12 intake had higher serum B12 than those who did not. Overall 45.9% of intakes fell below the Estimated Adequate Requirement. Dietary B12 intake of children and women was directly correlated with serum B12 (r = 0.18, p < 0.001 and r = 0.11, p = 0.0304). The prevalence of marginal and deficient B12 status in 1999 was much higher than the most recently published national data suggesting the success of national policies to improve micronutrient status.

A descriptive study of clinico-hematological profile of megaloblastic anemia in a tertiary care hospital

Background

Megaloblastic Anemia (MA) is a relatively common disease, yet the data on prevalence of MA remains scarce. This study was conducted to study the prevalence and clinico-hematological profile of MA.

Methods

This was a cross-sectional study done on 1150 adult anemic patients. All patients diagnosed to have MA were studied for clinico-hematological and etiological profile. Nerve conduction studies (NCS) were done in all.

Results

MA was present in 3.6% cases of anemia. Severe anemia was seen in 9.7% of anemic patients and 75% of MA cases (p < 0.05). Forty five percent of MA patients presented with pancytopenia. Vitamin B12 and folic acid deficiency were documented in 40% and 25% cases respectively while combined deficiency was noted in 35% of all MA cases. There was no co-relation between severity of anemia and deficiency of either of the vitamins (Fischer exact test: 0.530). Among MA patients, 35% were vegetarians while 65% consumed mixed diet. There was no association between vegetarian diet and Vit B12 deficiency (p = 0.3137). An additional etiology was more commonly found in patients on mixed diet [92%; 24/26] as compared to those on vegetarian diet [50%; 7/14] (p = 0.04). NCS was abnormal in 14 patients (35%). Overt clinical neuropathy was present in 12 cases of MA, while subclinical neuropathy was seen in 2 cases.

Conclusion

MA is one of common causes of pancytopenia and severe anemia. Diet plays an important role in causation of MA in vegetarians. An alternative etiology is however, more likely to be found in patients on mixed diet. While overt neurological abnormalities are common in MA, subclinical neuropathy is uncommon.

Should vitamin B12 status be considered in assessing risk of neural tube defects?

There is a strong biological premise for including vitamin B₁₂ with folic acid in strategies to prevent neural tube defects (NTDs), due to the closely interlinked metabolism of these two vitamins. For example, reduction of B₁₂ deficiency among women of reproductive age could enhance the capacity of folic acid to prevent NTDs by optimizing the cellular uptake and utilization of natural folate cofactors. Vitamin B₁₂ might also have an independent role in NTD prevention, such that adding it in fortification programs might be more effective than fortifying with folic acid alone. Globally, there is ample evidence of widespread vitamin B₁₂ deficiency in low‐ and middle‐income countries, but there is also considerable divergence of vitamin B₁₂ status across regions, likely due to genetic as well as nutritional factors. Here, I consider the evidence that low vitamin B₁₂ status may be an independent factor associated with risk of NTDs, and whether a fortification strategy to improve B₁₂ status would help reduce the prevalence of NTDs. I seek to identify knowledge gaps in this respect and specify research goals that would address these gaps.

Cross-sectional study of nutritional markers in pregnancy

OBJECTIVES

To note the value of serum Vitamin B12, folic acid, and ferritin in normal and high-risk pregnancies (HRPs) in patients attending antenatal clinic at All India Institute of Medical Sciences (AIIMS).

MATERIALS AND METHODS

This is a cross-sectional study where a total of 282 patients attending Gynaecology Outpatient Department at AIIMS, New Delhi, India were recruited. Among the 282 subjects, 251 were pregnant, and 31 were controls. The serum was tested for serum Vitamin B12, serum folic acid, and serum ferritin levels using Beckman Coulter Access 2 immunoassay.

RESULTS

The median value of serum folic acid level in pregnant women was 12 pg/ml with range being 2-20 pg/ml in contrast to 8 pg/ml with range being 3-20 pg/ml in nonpregnant female. This difference was statistically significant. (P = 0.05). There was no significant difference in the median level of serum Vitamin B12 and serum ferritin in pregnant and nonpregnant group. Serum Vitamin B12 level was lower in the third trimester (127 pg/ml) than in first trimester (171 pg/ml) and the difference is statistically significant (P = 0.03). Serum ferritin levels were also significantly lower in the second trimester (16.4 pg/ml) than third trimester (24.55 pg/ml). Although the median serum folic acid level was lower in the first trimester (9.84 pg/ml) than in second trimester (10.8 pg/ml) and in the third trimester (13.18 pg/ml) but the difference was not statistically significant. There was no significant difference in Vitamin B12 level in HRPs (median value 134 pg/ml) as compared to low-risk pregnancies (149.5 pg/ml).

CONCLUSION

Serum folic acid levels are significantly higher during pregnancy as compared to nonpregnant state. However, there was no significant difference in the median level of serum Vitamin B12 and serum ferritin in pregnant and nonpregnant group. Serum folic acid level and ferritin level were significantly higher in HRPs compared to low-risk pregnancies.

Vitamin B-12 Concentrations in Breast Milk Are Low and Are Not Associated with Reported Household Hunger, Recent Animal-Source Food, or Vitamin B-12 Intake in Women in Rural Kenya

BACKGROUND

Breast milk vitamin B-12 concentration may be inadequate in regions in which animal-source food consumption is low or infrequent. Vitamin B-12 deficiency causes megaloblastic anemia and impairs growth and development in children.

OBJECTIVE

We measured vitamin B-12 in breast milk and examined its associations with household hunger, recent animal-source food consumption, and vitamin B-12 intake.

METHODS

In a cross-sectional substudy nested within a cluster-randomized trial assessing water, sanitation, hygiene, and nutrition interventions in Kenya, we sampled 286 women 1-6 mo postpartum. Mothers hand-expressed breast milk 1 min into a feeding after 90 min observed nonbreastfeeding. The Household Hunger Scale was used to measure hunger, food intake in the previous week was measured with the use of a food-frequency questionnaire (FFQ), and vitamin B-12 intake was estimated by using 24-h dietary recall. An animal-source food score was based on 10 items from the FFQ (range: 0-70). Breast milk vitamin B-12 concentration was measured with the use of a solid-phase competitive chemiluminescent enzyme immunoassay and was modeled with linear regression. Generalized estimating equations were used to account for correlated observations at the cluster level.

RESULTS

Median (IQR) vitamin B-12 intake was 1.5 μg/d (0.3, 9.7 μg/d), and 60% of women consumed <2.4 μg/d, the estimated average requirement during lactation. Median (IQR) breast milk vitamin B-12 concentration was 113 pmol/L (61, 199 pmol/L); 89% had concentrations <310 pmol/L, the estimated adequate concentration. Moderate or severe hunger prevalence was 27%; the animal-source food score ranged from 0 to 30 item-d/wk. Hunger and recent animal-source food and vitamin B-12 intake were not associated with breast milk vitamin B-12 concentrations. Maternal age was negatively associated with breast milk vitamin B-12 concentrations.

CONCLUSION

Most lactating Kenyan women consumed less than the estimated average requirement of vitamin B-12 and had low breast milk vitamin B-12 concentrations. We recommend interventions that improve vitamin B-12 intake in lactating Kenyan women to foster maternal health and child development. The main trial was registered at clinicaltrials.gov as NCT01704105.

Folate and Vitamin B12 Status in Latin America and the Caribbean

Background:

The current magnitude of folate and vitamin B12 deficiency in Latin America and the Caribbean is uncertain.

Objective:

To summarize data on plasma or serum vitamin B12 and folate concentrations in Latin America and the Caribbean reported since 1990, a period that covers the era before and after the introduction of folic acid fortification.

Methods:

A systematic review was conducted in 2012 and updated in 2014. Studies and surveys using biochemical biomarkers and conducted in apparently healthy individuals were identified.

Results:

Folate deficiency in Latin America and the Caribbean appears not to be a public health problem (prevalence < 5%) after the introduction of folic acid fortification. However, there is some indication that high rates of low or marginal vitamin B12 status remain in most locations and across population groups.

Conclusions:

Adding vitamin B12 as a fortificant with folic acid may be the best strategy in areas where vitamin B12 deficiency is an established concern.

Vitamin B₁₂ and vegetarian diets

Vitamin B₁₂ is found almost exclusively in animal-based foods and is therefore a nutrient of potential concern for those following a vegetarian or vegan diet. Vegans, and anyone who significantly limits intake of animal-based foods, require vitamin B₁₂-fortified foods or supplements. Vitamin B₁₂ deficiency has several stages and may be present even if a person does not have anaemia. Anyone following a vegan or vegetarian diet should have their vitamin B₁₂ status regularly assessed to identify a potential problem. A useful process for assessing vitamin B₁₂ status in clinical practice is the combination of taking a diet history, testing serum vitamin B₁₂ level and testing homocysteine, holotranscobalamin II or methylmalonic acid serum levels. Pregnant and lactating vegan or vegetarian women should ensure an adequate intake of vitamin B₁₂ to provide for their developing baby. In people who can absorb vitamin B₁₂, small amounts (in line with the recommended dietary intake) and frequent (daily) doses appear to be more effective than infrequent large doses, including intramuscular injections. Fortification of a wider range of foods products with vitamin B₁₂, particularly foods commonly consumed by vegetarians, is likely to be beneficial, and the feasibility of this should be explored by relevant food authorities.

Disadvantaged pre-schoolers attending day care in Salvador, Northeast Brazil have a low prevalence of anaemia and micronutrient deficiencies

OBJECTIVE

To examine the micronutrient status of disadvantaged pre-schoolers from Northeast Brazil, following the introduction of pro-poor policies, by assessing the prevalence of anaemia and micronutrient deficiencies and the role of sociodemographic factors, genetic Hb disorders and parasitic infections.

DESIGN

In a cross-sectional study, data on sociodemographic status, health, growth, genetic Hb disorders, parasites and nutrient supply from day-care meals were obtained. Fasting blood samples were collected and analysed for Hb, serum ferritin, transferrin receptor, folate, vitamin B₁₂, retinol, Zn and Se.

SETTING

Seven philanthropic day-care centres serving urban slums in Salvador, Northeast Brazil.

SUBJECTS

Pre-schoolers aged 3-6 years from disadvantaged households.

RESULTS

Of the 376 sampled children, 94 % were of black or mixed race; 33 % and 29 % had at least one genetic Hb disorder and intestinal parasite, respectively. Stunting and underweight were ≤5 %; 14 % were overweight. Day-care centres supplied micronutrient-dense meals and snacks each weekday. Less than 10 % of pre-schoolers had anaemia and micronutrient deficiencies. Predictors (P < 0·05) of Hb were α(3·7) thalassaemia, Se and retinol (but not ferritin). Micronutrient predictors (P < 0·05) were: elevated α₁-glycoprotein for ferritin, Hb AS and BMI Z-score >1 for transferrin receptor, Zn and elevated α₁-glycoprotein for retinol, sex and helminths for Se, helminths for vitamin B₁₂, and Giardia intestinalis infection for serum folate.

CONCLUSIONS

Impaired growth, anaemia and micronutrient deficiencies were uncommon among these disadvantaged pre-schoolers attending day care. A range of interventions including provision of micronutrient-dense, fortified day-care meals, deworming and vitamin A supplementation likely contributed to improved micronutrient status, suggesting expanded coverage of these programmes.

Low vitamin B12 intake during pregnancy and lactation and low breastmilk vitamin 12 content in rural Kenyan women consuming predominantly maize diets

BACKGROUND

Vitamin B12 deficiency during pregnancy and lactation may negatively affect fetal growth, brain development, pregnancy outcome, and breastmilk vitamin B12 content.

OBJECTIVE

To examine associations between pregnant and lactating women's vitamin B12 intake and pregnancy outcomes, breastmilk vitamin B12 concentration, and growth and development of breastfed infants from birth to 6 months.

METHODS

One hundred thirty-eight Kenyan women were followed during pregnancy, with 98 followed through 6 months of lactation and providing 294 randomly collected breastmilk samples. Maternal hematologic analyses were performed for erythrocyte morphology, erythrocyte size, and serum vitamin B12 concentration. Women's and infants'food intake was assessed. Breastmilk vitamin B12 was measured by a competitive binding isotope dilution technique. Infant anthropometric data and the Brazelton Neonatal Behavioral Assessment Scale (BNBAS) were assessed within 3 days after birth. The Infant Bayley Motor Scale was assessed at 6 months. Statistical analyses included simple regression and correlation analyses in relation to vitamin B12 status and gestational age.

RESULTS

Intrauterine growth restriction and stillbirths were correlated with maternal macrocytic anemia and hypersegmented polymorphonuclear nuclei. Postpartum maternal vitamin B12 intake influenced breastmilk vitamin B12 levels 1 to 6 months postpartum. No associations were found between vitamin B12 intake during pregnancy or vitamin B12 levels in breastmilk and infant length, weight, or head circumference at birth or 6 months. Vitamin B12 intake during pregnancy was correlated with improved scores on infants' BNBAS reflex subscale (R = -0.19, p = .05) with adjustment for gestational age. Bayley Motor Scale results at 6 months were not significantly associated with breastmilk or supplemental feeding vitamin B12 content.

CONCLUSIONS

Vitamin B12 deficiency may adversely affect pregnancy outcome, infant reflexes at birth, and breastmilk vitamin B12 content.

Tremors and thrombocytosis during treatment of megaloblastic anaemia

In developing countries, a deficiency of cobalamine and folate contributes significantly to megaloblastic anaemia. Neurological observations in infants and young children with megaloblastic anaemia have included hypotonia, developmental regression, tremors and other abnormal movements. Following therapy with vitamin B12, coarse tremors occurred in six of 51 patients (12%) with megaloblastic anaemia. The tremors, which were noticed initially in the hands and feet, gradually became generalised and disappeared during sleep. They subsided within 5-11 days. Thirteen of 25 (52%) patients developed thrombocytosis between day 3 and week 5 of follow-up. In one child, the platelet count increased to >1300 x 10(9)/L. The importance of recognising these clinical findings during treatment of megaloblastic anaemia is emphasised.

Addition of cobalamin to iron and folic acid improves hemoglobin rise in nutritional anemia

OBJECTIVE

To assess whether addition of cobalamin (cbl) to iron-folic acid will result in improved response in nutritional anemia.

METHODS

This study included 150 children aged between 0.5-5 y having nutritional anemia. Anemia was categorized for severity and red cell morphology. Serum levels of ferritin were obtained in all cases while levels of cbl and folic acid (FA) were done only in children having macrocytic or dimorphic anemia. Children were randomized to receive either iron and FA (Group I) or iron, FA and cbl (Group II). Response to treatment was assessed at 2, 4 and 8 wk.

RESULTS

Of all the 150 patients, iron deficiency was documented in 111 patients. Of the 41 cases in whom, Cbl and FA levels were done, 97.56% and 53.66% had deficiency of cbl and FA respectively. Patients in group II had higher Hb level at 2, 4 and 8 wk (significant at 4 and 8 wk). Percentage Hb rise from baseline Hb was significantly higher in group II (p 0.00). In group II, increase in Hb among cases with macrocytosis and others were similar although percentage increase in Hb was more pronounced among patients with macrocytic anemia or dimorphic anemia. However, this difference was statistically not significant (p = 0.18).

CONCLUSIONS

Children receiving cbl in addition to iron and FA showed an improved hematological response.

Understanding Vitamin B12

Vitamin B12 (B12) is essential in activating folate needed in DNA synthesis. Inadequate intake results in the impairment of nerve transmission and inadequate synthesis of erythrocytes and other hematological cells. Two separate mechanisms of B12 absorption exist, a receptor-mediated endocytosis that occurs in the distal ileum and the mass-action pharmacologic mechanism. The recommended dietary allowance for B12 for adults issued by the Institute of Medicine is 2.4 µg/d. B12 is only found in meats and other foods of animal origin. B12 deficiency is widespread. Two main causes of deficiency include inadequate absorption and intake. Elderly and vegetarians are at highest risk for deficiency. Prevalence of deficiency ranges from 7% of the US population 3 years and older to 90% among vegans. The best way to assess deficiency is by using methylmalonic acid. Populations at risk could benefit from using B12 supplements and from fortification of flour.

The importance of methylmalonic acid dosage on the assessment of patients with neurological manifestations following bariatric surgery

Vitamin B12 or cyanocobalamin is an important substance that is included in several metabolic pathways. Its deficiency is a common event after bariatric surgery, decreasing the vitamin B12 absorption after almost all of the stomach and duodenum are eliminated from the digestion process. Neurological manifestations of cyanocobalamin deficiency are not uncommon. We report a case of a young woman who developed ataxia, weakness and peripheral neuropathy after bariatric surgery, but with normal value of vitamin B12 dosage. For the diagnosis, it was necessary to dose methylmalonic acid. We discuss the importance of methylmalonic acid dosage after bariatric surgery in patients who present suspect of cyanocobalamin deficiency with normal values of this vitamin and the role of proton pump inhibitor use and vitamin supplementation in patients with early neurological presentation.

Decreased vitamin b(12) levels in children with nocturnal enuresis

Objectives. Nocturnal enuresis is a common pediatric problem, the etiology of which is unclear. In the present study, vitamin B(12) and folate levels were measured in children with nocturnal enuresis and compared with those in healthy control group children to investigate whether there was any relation with enuresis and neurogenic maturation as a first time in the literature. Methods. In this cross-sectional study, we included thirty children (16 girls, 14 boys) who had presented with primary nocturnal enuresis (PNE) complaints in the study group and 31 children (13 girls, 18 boys) in the control group. Body weight and height measurements were obtained and complete blood counts and vitamin B(12) and folate levels were measured in all children. Results. No difference was found in age, height, and weight between study and control groups. Also the mean levels of the hemoglobin, hematocrit, and mean corpuscular volume (MCV) were not different between the two groups. Significantly lower mean vitamin B(12) and folate levels were found in the enuresis group compared with the control group. Conclusions. Further studies are needed to clarify B(12) and folate deficiency in larger series so that these tests can be included in routine investigations of enuretic children.

Multiple micronutrient supplementation improves vitamin B₁₂ and folate concentrations of HIV infected children in Uganda: a randomized controlled trial

Background

The effect of multiple micronutrient supplementation on vitamin B₁₂ and folate has hither to not been reported in African HIV infected children. This paper describes vitamin B₁₂ and folate status of Ugandan HIV infected children aged 1-5 years and reports the effect of multiple micronutrient supplementation on serum vitamin B₁₂ and folate concentrations.

Methods

Of 847 children who participated in a multiple micronutrient supplementation trial, 214 were assessed for vitamin B₁₂ and folate concentrations pre and post supplementation. One hundred and four children were randomised to two times the recommended dietary allowance (RDA) of a 14 multiple micronutrient supplement (MMS) and 114 to a 'standard of care' supplement of 6 multivitamins (MV). Serum vitamin B₁₂ was measured by an electrochemiluminescence immunoassay and folate by a competitive protein-binding assay using Modular E (Roche) automatic analyzer. Vitamin B₁₂ concentrations were considered low if less than 221picomoles per litre (pmol/L) and folate if < 13.4 nanomoles per litre (nmol/L). The Wilcoxon Signed Ranks test was used to measure the difference between pre and post supplementation concentrations.

Results

Vitamin B₁₂ was low in 60/214 (28%) and folate in 62/214 (29.0%) children. In the MMS group, the median concentration (IQR) of vitamin B₁₂ at 6 months was 401.5 (264.3 - 518.8) pmol/L compared to the baseline of 285.5 (216.5 - 371.8) pmol/L, p < 0.001. The median (IQR) folate concentrations increased from 17.3 (13.5 - 26.6) nmol/L to 27.7 (21.1 - 33.4) nmol/L, p < 0.001. In the 'standard of care' MV supplemented group, the median concentration (IQR) of vitamin B₁₂ at 6 months was 288.5 (198.8 - 391.0) pmol/L compared to the baseline of 280.0 (211.5 - 386.3) pmol/L while the median (IQR) folate concentrations at 6 months were 16.5 (11.7 - 22.1) nmol/L compared to 15.7 (11.9 - 22.1) nmol/L at baseline. There was a significant difference in the MMS group in both vitamin B₁₂ and folate concentrations but no difference in the MV group.

Conclusions

Almost a third of the HIV infected Ugandan children aged 1-5 years had low serum concentrations of vitamin B₁₂ and folate. Multiple micronutrient supplementation compared to the 'standard of care' supplement of 6 multivitamins improved the vitamin B₁₂ and folate status of HIV infected children in Uganda.

Trial registration

http://ClinicalTrials.govNCT00122941)

Relationship between the Levels of Holotranscobalamin and Vitamin B12

To date, the determination of serum vitamin B12 levels has been the most common laboratory test for the assessment of vitamin B12 status; however, the diagnostic accuracy of this test is low. To obtain a more sensitive marker, a new test to measure holotranscobalamin (holoTC) levels has been introduced. In this study, we assessed 45 patients for whom a vitamin B12 test had been requested and 139 anemic patients. We investigated the associations between the levels of homocysteine (Hcy) and those of holoTC, serum vitamin B12, and folate and assessed the diagnostic value of holoTC levels as a marker for vitamin B12 deficiency. We also determined the precision of the AxSYM holoTC assay by calculating the coefficient of variance (CV). The within-run and between-run precision values were excellent, as all CV values were less than 3.5%. The holoTC levels were low (<35 pmol/L) in 7 samples, and 6 of these samples had normal total serum vitamin B12 levels. In 2 of these samples, high Hcy levels (>12 micromol/L) indicated vitamin B12 deficiency. Thus, the holoTC levels were more sensitive than the serum vitamin B12 levels for indicating vitamin B12 status. If the serum vitamin B12 level is 151-300 pmol/L, the levels of holoTC alone or in combination with serum vitamin B12 levels are likely to be more useful markers than serum vitamin B12 levels alone.

Megaloblastic anemia: back in focus

Megaloblastic anemia (MA), in most instances in developing countries, results from deficiency of vitamin B(12) or folic acid. Over the last two to three decades, incidence of MA seems to be increasing. Of the two micronutrients, folic acid deficiency contributed to MA in a large majority of cases. Now deficiency of B(12) is far more common. In addition to anemia, occurrence of neutropenia and/or thrombocytopenia is increasingly being reported. Among cases presenting with pancytopenia, MA stands out as an important (commonest cause in some series) cause. This article focuses on these and certain other aspects of MA. Possible causes of increasing incidence of MA are discussed. Observations on other clinical features like neurocognitive dysfunction, associated hyperhomocysteinemeia and occurrence of tremors and thrombocytosis during treatment are highlighted.

Nutritional Status of Primary Schoolchildren in Garhwali Himalayan Villages of India

Background

Anemia and micronutrient deficiencies are common among Indian schoolchildren. However, past studies have narrowly focused on only a few micronutrients and have not carefully evaluated the association between sociodemographic factors and nutritional status of schoolchildren.

Objective

To assess the nutritional status of schioolchildren in Himalayan villages of India and to determine the relationships between their nutritional status, intestinal helminth infection, and sociodemographic characteristics.

Methods

A random sample of 499 children 6 to 10 years of age from 20 public primary schools was selected. Household sociodemographic data and morbidity data on children were collected through interviews with their caretakers. Height and weight were measured, and venous blood was drawn for assessment of hemoglobin, serum ferritin, soluble transferrin receptor, retinol, zinc, folic acid, vitamin B12, and C-reactive protein. Stool samples were analyzed for parasitic infections.

Results

Underweight, stunting, and wasting were present in 60.9%, 56.1%, and 12.2% of schoolchildren, respectively. Anemia, iron-deficiency anemia, and low serum concentrations of ferritin, zinc, retinol, folate, and vitamin B12 were found in 36.7%, 10.2%, 24.1%, 57.1%, 56.1%, 67.9%, and 17.4% of the children, respectively. One-fifth of the children had intestinal parasites. Being underweight was associated with lower household wealth ( p < .05). Helminth infection was associated with stunting, anemia, and low serum retinol ( p < .05). Living at higher altitude was associated with low serum levels of ferritin, retinol, and vitamin B12. There were no associations between any sociodemographic variables and serum zinc or folate.

Conclusions

Growth impairment and micronutrient deficiencies are prevalent among schoolchildren in Himalayan villages of India.

Severe pernicious anaemia in an 8-year-old African girl

An 8-year-old girl presented with severe muscular weakness, peripheral neuropathy, ataxia, fever and macrocytic anaemia. Clinically, vitamin B(12) (cobalamin) deficiency was considered. Despite the lack of pre-treatment laboratory confirmation of the diagnosis, a therapeutic trial of hydroxocobalamin injections was begun. After several days, a partial clinical response was seen. Within 5 months all symptoms had resolved. After treatment was initiated, laboratory analysis of pre-treatment blood samples confirmed the presence of vitamin B(12) deficiency. Auto-antibodies to intrinsic factor and parietal cells, pathognomonic for pernicious anaemia, were confirmed. Vitamin B(12) deficiency owing to dietary deficiency is not uncommon in children in developing countries. Although nutritional deficiency might have played a role in our patient, this case illustrates that the neurological manifestations of pernicious anaemia can present at a young age in African populations.

Evaluation of vitamin B12status in Egypt IV: Food consumption patterns among lactating mothers and their impact on the intake of the vitamin

The adequacy of vitamin B12 intake was assessed among 62 lactating mothers in the 2-32 weeks of lactation by an interactive 24-h recall and an open-ended food frequency questionnaire. Double portions of the foods consumed were sampled and assayed microbiologically for its vitamin B12 content. Based on the food item and its respective vitamin B12 content, combined with the usual portion size in grams and the frequency of consumption, a rapid calculator of approximate dietary vitamin B12 intake was developed. The estimated vitamin B12 intake averaged 4.17+/-0.74 microg/d. Only 25.8% of the lactating mothers had adequate vitamin B12 intake (>2.5 microg vitamin B12 daily). Three quarter of the studied population were consuming vitamin B12<2.5 microg/d. Out of those, 50% had estimated daily intake <2.0 microg/d. This percentage prevalence confirms the additional burden on the lactating mothers to satisfy the daily vitamin B12 requirement for its breast-fed baby.

Severe vitamin B-12 deficiency in a child mimicking thrombotic thrombocytopenic purpura

We report a case of severe vitamin B-12 deficiency in a child who had a clinical presentation of hemolysis and thrombocytopenia that suggested the diagnosis of thrombotic thrombocytopenic purpura (TTP) and was associated with decreased ADAMTS13 activity. In this report, we review vitamin B-12 deficiency in children, the relationship between ADAMTS13 activity and TTP and discuss other conditions associated with decreased ADAMTS13 activity.

Vitamin B-12 status is associated with socioeconomic level and adherence to an animal food dietary pattern in Colombian school children

Vitamin B-12 is related to neurocognitive function in school-age children, yet sociodemographic and dietary correlates of vitamin B-12 status in this age group are not well characterized. The prevalences of vitamin B-12 or folate deficiencies in Colombia are unknown. We conducted a cross-sectional study in a representative sample of 2800 low- and middle-income children aged 5-12 y from Bogotá's public schools. Plasma vitamin B-12 and erythrocyte folate concentrations (mean +/- SD) were 327 +/- 106 pmol/L and 858 +/- 256 nmol/L, respectively. The prevalence of vitamin B-12 deficiency (<148 pmol/L) was 1.6% and the prevalence of marginal status (148-221 pmol/L) was 15.0%. Only 2 children had folate deficiency (<305 nmol/L). In multivariate analysis, mean vitamin B-12 concentrations significantly decreased with age and were 15 pmol/L higher in girls than boys (95%CI = 8, 23). Vitamin B-12 was inversely related to the mother's parity and positively associated with the amount of money spent on food per person per day at home and the household's neighborhood socioeconomic status (SES) classification. Folate concentrations were lower in girls than in boys and significantly increased with the household's SES. We identified 4 dietary patterns with principal components analysis of a FFQ in a random subsample (n = 972). Plasma vitamin B-12 was strongly, positively associated with a pattern that included frequent intake of beef, chicken, and dairy products in a dose-response manner (P-trend, adjusted, = 0.008). Low vitamin B-12 status is not negligible in Colombian school children and is associated with poverty and marginal intake of animal food sources.

Common metabolic profile in infants indicating impaired cobalamin status responds to cobalamin supplementation

OBJECTIVE

A metabolic profile consistent with impaired cobalamin status is prevalent in breastfed infants. We investigated whether this profile reflects immature organ systems or impaired cobalamin status.

METHODS

In a single-center, randomized, placebo-controlled trial, we studied 107 six-week-old infants. The infants were randomly assigned to receive either an intramuscular injection of 400 mug of cobalamin or no intervention. Concentrations of cobalamin and folate in serum and total homocysteine, methylmalonic acid, and cystathionine in plasma were determined at enrollment and at the age of 4 months.

RESULTS

There were no significant differences between the intervention group (n = 54) and the control group (n = 53) in the concentrations of any vitamin marker at baseline (6 weeks). At 4 months, the supplement-treated infants had a 75% higher median serum cobalamin level and remarkable reductions in median plasma total homocysteine (from 7.46 to 4.57 micromol/L) and methylmalonic acid (from 0.58 to 0.20 micromol/L) levels, whereas levels of both metabolites were essentially unchanged during the follow-up period in the control group.

CONCLUSIONS

Cobalamin supplementation changed all markers of impaired cobalamin status (low cobalamin, high total homocysteine, and high methylmalonic acid levels) toward a profile observed in cobalamin-replete older children and adults. Therefore, the high total homocysteine and methylmalonic acid levels reported for a large fraction of infants reflect not immature metabolism but rather insufficient cobalamin levels to fully sustain cobalamin-dependent reactions fully.

Causes of Vitamin B12 and Folate Deficiency

This review describes current knowledge of the main causes of vitamin B12 and folate deficiency. The most common explanations for poor vitamin B12 status are a low dietary intake of the vitamin (i.e., a low intake of animal-source foods) and malabsorption. Although it has long been known that strict vegetarians (vegans) are at risk for vitamin B12 deficiency, evidence now indicates that low intakes of animal-source foods, such as occur in some lacto-ovo vegetarians and many less-industrialized countries, cause vitamin B12 depletion. Malabsorption of the vitamin is most commonly observed as food-bound cobalamin malabsorption due to gastric atrophy in the elderly, and probably as a result of Helicobacter pylori infection. There is growing evidence that gene polymorphisms in transcobalamins affect plasma vitamin B12 concentrations. The primary cause of folate deficiency is low intake of sources rich in the vitamin, such as legumes and green leafy vegetables, and the consumption of these foods may explain why folate status can be adequate in relatively poor populations. Other situations in which the risk of folate deficiency increases include lactation and alcoholism.

Prevalence of anemia and deficiency of iron, folic acid, and zinc in children younger than 2 years of age who use the health services provided by the Mexican Social Security Institute

BACKGROUND

In Mexico, as in other developing countries, micronutrient deficiencies are common in infants between 6 and 24 months of age and are an important public health problem. The objective of this study was to determine the prevalence of anemia and of iron, folic acid, and zinc deficiencies in Mexican children under 2 years of age who use the health care services provided by the Mexican Institute for Social Security (IMSS).

METHODS

A nationwide survey was conducted with a representative sample of children younger than 2 years of age, beneficiaries, and users of health care services provided by IMSS through its regular regimen (located in urban populations) and its Oportunidades program (services offered in rural areas). A subsample of 4,955 clinically healthy children was studied to determine their micronutrient status. A venous blood sample was drawn to determine hemoglobin, serum ferritin, percent of transferrin saturation, zinc, and folic acid. Descriptive statistics include point estimates and 95% confidence intervals for the sample and projections for the larger population from which the sample was drawn.

RESULTS

Twenty percent of children younger than 2 years of age had anemia, and 27.8% (rural) to 32.6% (urban) had iron deficiency; more than 50% of anemia was not associated with low ferritin concentrations. Iron stores were more depleted as age increased. Low serum zinc and folic acid deficiencies were 28% and 10%, respectively, in the urban areas, and 13% and 8%, respectively, in rural areas. The prevalence of simultaneous iron and zinc deficiencies was 9.2% and 2.7% in urban and rural areas. Children with anemia have higher percentages of folic acid deficiency than children with normal iron status.

CONCLUSION

Iron and zinc deficiencies constitute the principal micronutrient deficiencies in Mexican children younger than 2 years old who use the health care services provided by IMSS. Anemia not associated with low ferritin values was more prevalent than iron-deficiency anemia. The presence of micronutrient deficiencies at this early age calls for effective preventive public nutrition programs to address them.

Prevalent vitamin B-12 deficiency in twelve-month-old Guatemalan infants is predicted by maternal B-12 deficiency and infant diet

Approximately one-third of low-income women and children studied in Guatemala are reported to have deficient (<148 pmol/L) or marginal (148-220 pmol/L) plasma vitamin B-12 concentrations. Because vitamin B-12 deficiency can adversely affect infant development and cognitive function, the present study examined predictors of deficient plasma vitamin B-12 concentrations at the age of 12 mo. Analyses were performed on baseline data from a randomized clinical trial in 304 Guatemalan infants, 80% of whom were partially breast-fed, and their mothers. Exclusion criteria for infants included twins, severe stunting or moderate wasting, reported major health problems, severe developmental delay, hemoglobin <95 g/L, maternal age <17 y, and maternal pregnancy >3 mo. Data collected included socio-economic status, infant anthropometry, vitamin B-12 intake from complementary foods, and breast-feeding frequency reported by mothers. A complete blood count and plasma vitamin B-12, folate, ferritin, and C-reactive protein were measured. Deficient or marginal plasma vitamin B-12 concentrations were found in 49% of infants and 68% of mothers. The mean intake of maternal vitamin B-12 was 3.1 microg/d, and infants consumed 2.2 microg/d from complementary foods. In linear regression analysis, infant plasma B-12 concentration was strongly and positively associated with maternal plasma vitamin B-12 and B-12 intake from complementary foods (predominantly powdered cow's milk), and inversely associated with frequency of breast-feeding and larger household size (P < 0.0001). Vitamin B-12 supplementation of lactating women, food fortification, and education to improve infant's vitamin B-12 status are potential interventions that can improve the vitamin B-12 status of mothers and infants in this population.

Diabetes and hypertension increases in a society with abdominal obesity: results of the Mexican National Health Survey 2000

Objectives:

To determine the prevalences of overweight, obesity, type 2 diabetes mellitus (DM) and hypertension (HT) in the Mexican population and compare them with those of a previous Mexican urban survey and an American survey.

Design:

A structured, randomised, nationally representative Mexican sample was compared with a 1993 Mexican urban survey and the US Third National Health and Nutrition Examination Survey (NHANES III) of non-Hispanic Whites.

Setting:

The Mexican National Health Survey 2000.

Subjects:

Subjects were 12856 men and 28332 women, aged 20–69 years, who had their body weight, height, waist circumference (WC), blood pressure and fasting capillary blood glucose measured.

Results:

Mexican adult men and women had a high prevalence of overweight (41.3 and 36.3%, respectively) and obesity (19.4 and 29.0%, respectively), similar to those in the USA in 1988–1992 and exceeding those of the 1993 Mexican survey. The prevalence of HT was 33.3% in men and 25.6% in women, with inferred DM rates of 5.6 and 9.7%, respectively. Abdominal obesity affected 46.3% of men (WC ≥ 94 cm) and 81.4% of women (WC ≥ 80 cm). There was a high prevalence of abdominal obesity in normal-weight women, with co-morbidities relating better to WC than to body mass index (BMI) in both sexes. Rates of DM and HT exceeded US rates on a comparable BMI or WC basis in adults aged <50 years.

Conclusion:

The high prevalence of obesity and abdominal obesity in Mexicans is associated with markedly increased prevalences of DM and HT to levels comparable with, or even higher than, those in NHANES III of non-Hispanic Whites.

Benefits and risks of breastfeeding

In the absence of significant, unpreventable risks, breastfeeding should be the norm for the nourishment of human infants and should, therefore, be encouraged for populations in all countries. Continued efforts of international and national agencies and healthcare professionals to aid and abet breastfeeding, reduce the risks that occur in some women during breastfeeding, provide the safest substitutes for human milk when that is necessary, and encourage further research into the posed questions should considerably improve the health of many children.

Nutritional vitamin B12 deficiency in hospitalized young children

The authors sought to determine prevalence, social, economic, and dietary patterns of young children (n = 20) identified as having vitamin B12 deficiency anemia after admission to their hospital in the last 3 years. The diagnosis of vitamin B12 deficiency was based on symptoms and clinical findings, findings on peripheral blood films and bone marrow aspirates, and serum levels of vitamin B12. The children had been exclusively breast-fed without any animal food supplementation. Serum vitamin B12 levels were also measured in the sera of mothers and found to be low. The authors concluded that vitamin B12 deficiency might be an important health problem among children of mothers who do not consume animal foods adequately.

Nutritional megaloblastic anemia in young Turkish children is associated with vitamin B-12 deficiency and psychomotor retardation

We aimed to investigate the presence of psychomotor retardation, physical and laboratory examination in infants with megaloblastic anemia. Inclusion criteria for the study were; age 9 to 36 months, refusal of food except for breast and cow milk, loss of appetite, developmental delay, significant pallor, and hypersegmentation neutrophils in the peripheral blood smear. A total of 33 children fulfilling the inclusion criteria were enrolled among 3368 patients attending Pediatric Outpatient Clinics of şirnak-Cizre State Hospital between January 25, 2004 and May 5, 2004. Mean age was 16.4 months. Thirty-two patients had Vitamin B12 deficiency, 1 patient had folate deficiency, and 10 patients had combined vitamin B12 and folate deficiency. Statistically, a positive significant relationship was detected between serum vitamin B12 levels and mean corpuscular volume (P = 0.001, r = 0.56), and between vitamin B12 levels and hemoglobin (P = 0.004, r = 0.49). We believe that preventative measures such as fortification of flour with vitamin B12, nutritional support with vitamin B12 for the mother during pregnancy and nursing, provision of adequate primary preventive health services, and starting complementary food after 6 months of age are important determinants for preventing megaloblastic anemia.

Understanding the increased risk of neural tube defect-affected pregnancies among Mexico-born women in California: immigration and anthropometric factors

Mexico-born women in the United States have an unexplained twofold increased risk of neural tube defect (NTD)-affected pregnancies. We examined whether immigration characteristics were associated with the NTD risk and whether anthropometric factors contributed to the increased risk among Mexico-born women. Data were derived from a large population-based case-control study in California. In-person interviews were conducted with mothers of 538 (88% of eligible) NTD-affected fetuses/infants and mothers of 539 (88%) randomly selected non-malformed control infants. The crude odds ratio (OR) for NTDs among all Mexico-born women, women residing <2 years in the US, and women >16 years old at immigration compared with non-Hispanic white women was 2.4 [95% confidence interval (CI) = 1.8, 3.3], 7.2 [95% CI = 3.7, 14.0] and 3.0 [95% CI = 2.0, 4.4], respectively. Risk for second- or third-generation Mexican-Americans was similar to that of white women. The crude OR for all Mexico-born women was reduced from 2.4 to 2.0 [95% CI = 1.3, 3.0] and for those residing <2 years in the US from 8.4 to 7.1 [95% CI = 3.2, 15.3] after adjustment for maternal body mass index (BMI), height, compromised diet, diabetes, and other known risk factors. In term pregnancies, additional adjustment for pregnancy weight gain reduced the OR in all Mexico-born women and recent immigrants by 16% and 25%, respectively. Low pregnancy weight gain (<10 vs. 10-14 kg) was particularly associated with increased NTD risk among Mexico-born women (OR(ADJ) = 5.8; 95% CI = 2.1, 15.8). Findings indicate that recent Mexican immigrants have a sevenfold increased risk for NTDs. Maternal BMI and height contributed very little, and inadequate weight gain contributed modestly to the NTD risk disparity for Mexican immigrants.

Dietary and genetic determinants of homocysteine levels among Mexican women of reproductive age

OBJECTIVE

To evaluate the independent and joint effects of dietary folate, vitamin B(12) consumption and methylenetetrahydrofolate reductase (MTHFR) polymorphisms (677C>T and 1298A>C) on the circulating folate and homocysteine (Hcy) levels among Mexican women of reproductive age.

DESIGN

A cross-sectional, population-based study.

SUBJECTS

The first 130 healthy non-pregnant women (aged 16-34 years) who agreed to participate in a reproductive cohort in Morelos, Mexico.

MAIN OUTCOME MEASUREMENTS

Dietary intakes of vitamin B(12) and folate were estimated using a semiquantitative food frequency questionnaire. MTHFR 677C>T and 1298A>C polymorphisms were ascertained using the PCR-based method. Serum levels of Hcy and folate were determined using high-performance liquid chromatography and radioimmunoassay, respectively.

RESULTS

Genotype frequencies for the MTHFR 677C>T polymorphism were 21.5% (CC), 52.3% (CT) and 26.2% (TT) among Mexican women. Of the population, 22% had the MTHFR 1298AC genotype, while no individual carried the 1298CC genotype. We observed an increased level of Hcy among carriers of the 677TT genotype, compared to carriers of the 677CC genotype. The highest level of Hcy was observed among MTHFR 677TT carriers with low B(12) intake (<2.0 microg/day), which resulted with a significant interaction (P=0.01).

CONCLUSION

Vitamin B(12) is an important determinant of Hcy levels in Mexico. Supplementation of folic acid with vitamin B(12) may be preferable when the MTHFR 677T variant allele is prevalent.

High prevalence of folic acid and vitamin B12 deficiencies in infants, children, adolescents and pregnant women in Venezuela

BACKGROUND

There is increased worldwide concern about the consequences of folic acid and vitamin B12 deficiencies on health, which include megaloblastic anemia, neural tube defects and cardiovascular disease.

OBJECTIVE

This study intended to determine the prevalence of folic acid and vitamin B12 deficiencies in vulnerable groups in labor and poor socioeconomic strata of the Venezuelan population.

METHODS

A total of 5658 serum samples were processed to determine folic acid and vitamin B12 concentrations. The study involved three surveys performed during 2001-2002 and included infants, children, adolescents and pregnant women from labor and poor socioeconomic strata of the population. The method used was a radio immunoassay designed for the simultaneous measurement of serum folic acid and vitamin B12.

RESULTS

The prevalence of folic acid deficiency was higher than 30% for all groups studied, reaching 81.79% in adolescents. Vitamin B12 deficiency was 11.4% in samples collected nationwide, but there was also a similar prevalence of high serum levels. The prevalence of folic acid and vitamin B12 deficiencies in pregnant women reached 36.32 and 61.34%, respectively.

CONCLUSION

This work shows that there is a high prevalence of folic acid deficiency, especially in women of reproductive age, pregnant adolescents and in the whole population studied in Vargas state. This situation requires immediate intervention as supplementation or food fortification programs.

Diabetes and hypertension increases in a society with abdominal obesity: results of the Mexican National Health Survey 2000

Objectives

To determine the prevalences of overweight, obesity, type 2 diabetes mellitus (DM) and hypertension (HT) in the Mexican population and compare them with those of a previous Mexican urban survey and an American survey.

Design

A structured, randomised, nationally representative Mexican sample was compared with a 1993 Mexican urban survey and the US Third National Health and Nutrition Examination Survey (NHANES III) of non-Hispanic Whites.

Setting

The Mexican National Health Survey 2000.

Subjects

Subjects were 12856 men and 28332 women, aged 20–69 years, who had their body weight, height, waist circumference (WC), blood pressure and fasting capillary blood glucose measured.

Results

Mexican adult men and women had a high prevalence of overweight (41.3 and 36.3%, respectively) and obesity (19.4 and 29.0%, respectively), similar to those in the USA in 1988–1992 and exceeding those of the 1993 Mexican survey. The prevalence of HT was 33.3% in men and 25.6% in women, with inferred DM rates of 5.6 and 9.7%, respectively. Abdominal obesity affected 46.3% of men (WC ≥ 94 cm) and 81.4% of women (WC ≥ 80 cm). There was a high prevalence of abdominal obesity in normal-weight women, with co-morbidities relating better to WC than to body mass index (BMI) in both sexes. Rates of DM and HT exceeded US rates on a comparable BMI or WC basis in adults aged <50 years.

Conclusion

The high prevalence of obesity and abdominal obesity in Mexicans is associated with markedly increased prevalences of DM and HT to levels comparable with, or even higher than, those in NHANES III of non-Hispanic Whites.

Child nutrition in developing countries

Malnutrition permeates all aspects of health, growth, cognition, motor and social development of young children in developing countries. More than 50% of deaths in these children can be attributed to malnutrition, most often in conjunction with serious infection. Irreversible and lifelong sequelae prevent children from reaching their full potential. Child survival initiatives and programs have accomplished much to save the lives of children from common and preventable illnesses, but the quality of the survivors' health needs to be improved, with much more attention paid to nutrition of the preschool and school child. Promotion of nutritional health must become an integral part of primary health services, especially for infants, preschoolers, schoolchildren, and women. Promotion of exclusive breastfeeding and appropriate complementary feeding and weaning are essential inputs. A daunting challenge is to improve diet quality through the raising and consumption of small animals by rural subsistence households to enhance maternal and child nutrition. School feeding from preschool onward must be an integral part of education so children are in a condition to learn. An excellent example of such programs is the WHO initiated Integrated Management of Childhood Illness, which integrates nutrition into the care of both sick and well children. The Early Child Development Program initiated by the World Bank and UNICEF has taken hold in many countries. Nutrition outcomes are closely linked with health and education activities starting in the preconception period through pregnancy, lactation, and childhood. Investment in human capital early in life will optimize the growth and social and economic development of children, families, and communities.

Vitamin B12 deficiency as a worldwide problem

Pernicious anemia is a common cause of megaloblastic anemia throughout the world and especially in persons of European or African descent. Dietary deficiency of vitamin B12 due to vegetarianism is increasing and causes hyperhomocysteinemia. The breast-fed infant of a vitamin B12-deficient mother is at risk for severe developmental abnormalities, growth failure, and anemia. Elevated methylmalonic acid and/or total homocysteine are sensitive indicators of vitamin B12-deficient diets and correlate with clinical abnormalities. Dietary vitamin B12 deficiency is a severe problem in the Indian subcontinent, Mexico, Central and South America, and selected areas in Africa. Dietary vitamin B12 deficiency is not prevalent in Asia, except in vegetarians. Areas for research include intermittent vitamin B12 supplement dosing and better measurements of the bioavailability of B12 in fermented vegetarian foods and algae.

Folate and Vitamin B12Status in the Americas

There is growing interest in the potential for folic acid fortification in the Americas and recognition of the high prevalence of low plasma vitamin B12 concentrations reported in various studies. This review summarized available data on plasma vitamin B12 and folate concentrations in the Americas. At least 40% of individuals had deficient or marginal plasma vitamin B12 concentrations in almost all locations and across age groups. Low plasma folate concentrations were less common. It is hypothesized that vitamin B12 deficiency may result from a low intake of animal source foods, while a higher intake of refined flour may result in low plasma folate.

Nutritional status of indigenous children at boarding schools in northern Mexico

OBJECTIVE

To assess the nutritional status of Tarahumara children at indigenous boarding schools.

DESIGN

Cross-sectional comprehensive nutritional survey.

SETTING

The schools sampled were located in indigenous municipalities of the northern Mexican state of Chihuahua.

SUBJECTS

The study was carried out in 2001 among 331 children aged 6-14 y from a sample of five schools. Anthropometric measurements, a thyroid exam and capillary haemoglobin levels were obtained from the children. Serum concentrations of ferritin, iron, total iron-binding capacity, vitamin B(12), folic acid and zinc were collected from a subsample of 100 children.

RESULTS

The prevalence of wasting and overweight (children 6-9 y) was 1.1 and 4.6%, respectively, and of underweight, risk of overweight and overweight (10-14 y) was 3.2, 5.1 and 0.6%, respectively. Stunting (6-12 y) was present in 22.3% of the children. The total goitre rate was 5.4%. The prevalence of anaemia was 13% (boys 11.4, girls 14.5%). Overall, 24.2% of the children were iron deficient (depletion 11.1%, deficient erythropoiesis 3%, iron deficiency anaemia 10.1%). No child had folic acid values <3 ng/ml, but 20.2% had low (<200 microg/dl) and 27.3% marginal (200-300 microg/dl) vitamin B(12) levels, and 80.2% had low zinc concentrations (<60 microg/dl).

CONCLUSIONS

Nutritional underweight and stunting were similar to those reported in rural localities at the national level, but overweight was less prevalent in children aged 10-14 y. Various micronutrient deficiencies was identified including zinc and vitamin B(12), but the prevalence of iron and folic acid deficiency was lower than expected. These results suggest that Tarahumara children attending boarding schools may be the better-off children from these extremely poor and marginalized areas.

SPONSORSHIP

Swedish Agency for Research Cooperation with Developing Countries and the Mexican Social Security Institute.