Role of B₁₂ and homocysteine status in determining BMD and bone turnover in young Indians

Status of Vitamin B12 among Healthy Adult and Elderly Population in India: A Review

Vitamin B₁₂ is a water soluble micronutrient found in animal foods. Its deficiency is not uncommon in India owing to vegetarianism but often unrecognized due to diverse clinical manifestations. This review aims to collate the current data on vitamin B₁₂ status in healthy Indian adult and elderly population. Online database Pubmed was searched for articles published in English between 2000 and 2019. Inclusion criteria consisted of original studies conducted on apparently healthy adult and elderly Indian population reporting serum/plasma vitamin B₁₂ levels. Comprehensive literature search identified 14 studies eligible for inclusion. The deficiency prevalence reached 78.5% and 61.7% among adults and elderly, respectively, based on varying cut offs. Higher vitamin B₁₂ levels were reported in women than men. Hyperhomocysteinemia (Hcy >15 μmol/L) was lower in females as compared to males (60% vs 90%, 14.9% vs 57.4% and 3.6% vs 20.9% respectively in three studies). Vitamin B₁₂ deficiency was higher in vegetarians. The results indicate that inadequate vitamin B₁₂ status is a wide spread problem in the Indian population. However, variety of laboratory methods and cut-offs of vitamin B₁₂ deficiency and the heterogeneity in results pose challenges to draw clear conclusions on the extent of vitamin B₁₂ deficiency in India. This review, therefore, highlights the need for more evidence based research to define age and sex specific cut offs for defining vitamin B₁₂ deficiency.

Association between plasma total homocysteine level within normal range and bone mineral density in adults

BACKGROUND

Growing evidence indicates that homocysteine is a noteworthy marker for general health status. However, research regarding plasma total homocysteine (tHcy) levels and bone mineral density (BMD) is sparse and controversial. Hence, we aimed to investigate the association between plasma tHcy level within normal range and lumbar BMD in adults.

METHODS

In this cross-sectional study, using the National Health and Nutrition Examination Survey database, data on 10748 adults aged between 30 and 85 years were analyzed. The weighted multiple logistic regression analyses were conducted to evaluate the association between plasma tHcy level and lumbar BMD. The fitted smoothing curves were performed to explore potential non-linear relationships. When non-linearity was detected, we further calculated the inflection point using a recursive algorithm and constructed a weighted two-piecewise linear regression model.

RESULTS

After adjusting for all the covariates, the association between plasma tHcy and lumbar BMD was different in various age groups (adults aged 30-49 years: β = -0.0004, 95% CI -0.0025, 0.0018; adults aged 50-69 years: β = 0.0001, 95% CI -0.0025, 0.0026; adults aged 70-85 years: β = 0.0050, 95% CI 0.0008, 0.0092). In the subgroup analysis stratified by gender, this association also differed based on gender. There was a negative trend in females (aged 30-49 years: β = -0.0022, 95% CI -0.0054, 0.0011; aged 50-69 years: β = -0.0028, 95% CI -0.0062, 0.0007), and a positive trend in males (aged 30-49 years: β = 0.0018, 95% CI -0.0012, 0.0048; aged 50-69 years: β = 0.0027, 95% CI -0.0009, 0.0063) in both 30-49 years group and 50-69 years group. In the 70-85 years group, this association was significantly positive in males (β = 0.0136, 95% CI 0.0068, 0.0204), but was not significantly different in females (β = 0.0007, 95% CI -0.0046, 0.0060).

CONCLUSION

The correlation between plasma tHcy level within the normal range and lumbar BMD differs by age and gender.

Veganism, vegetarianism, bone mineral density, and fracture risk: a systematic review and meta-analysis

Context

The numbers of vegans and vegetarians have increased in the last decades. However, the impact of these diets on bone health is still under debate.

Objective

This systematic review and meta-analysis sought to study the impact of vegetarian and vegan diets on bone mineral density (BMD) and fracture risk.

Data Sources

A systematic search was conducted of PubMed, Scopus, and Science Direct, covering the period from the respective start date of each database to November 2017.

Data Extraction

Two investigators evaluated 275 studies against the inclusion criteria (original studies in humans, written in English or Spanish and including vegetarian or vegan diets and omnivorous diets as factors with BMD values for the whole body, lumbar spine, or femoral neck and/or the number of fractures as the outcome) and exclusion criteria (articles that did not include imaging or studies that included participants who had suffered a fracture before starting the vegetarian or vegan diet). The quality assessment tool for observational cohort and cross-sectional studies was used to assess the quality of the studies.

Results

Twenty studies including 37 134 participants met the inclusion criteria. Compared with omnivores, vegetarians and vegans had lower BMD at the femoral neck and lumbar spine and vegans also had higher fracture rates.

Conclusions

Vegetarian and vegan diets should be planned to avoid negative consequences on bone health.

Systematic Review Registration

PROSPERO registration no. CRD42017055508.

Contribution of food sources to the vitamin B12 status of South Indian children from a birth cohort recruited in the city of Mysore

OBJECTIVE

There is evidence that subclinical vitamin B12 (B12) deficiency is common in India. Vegetarianism is prevalent and therefore meat consumption is low. Our objective was to explore the contribution of B12-source foods and maternal B12 status during pregnancy to plasma B12 concentrations.

DESIGN

Maternal plasma B12 concentrations were measured during pregnancy. Children's dietary intakes and plasma B12 concentrations were measured at age 9.5 years; B12 and total energy intakes were calculated using food composition databases. We used linear regression to examine associations between maternal B12 status and children's intakes of B12 and B12-source foods, and children's plasma B12 concentrations.

SETTING

South Indian city of Mysore and surrounding rural areas.

SUBJECTS

Children from the Mysore Parthenon Birth Cohort (n 512, 47.1 % male).

RESULTS

Three per cent of children were B12 deficient (<150 pmol/l). A further 14 % had 'marginal' B12 concentrations (150-221 pmol/l). Children's total daily B12 intake and consumption frequencies of meat and fish, and micronutrient-enriched beverages were positively associated with plasma B12 concentrations (P=0.006, P=0.01 and P=0.04, respectively, adjusted for socio-economic indicators and maternal B12 status). Maternal pregnancy plasma B12 was associated with children's plasma B12 concentrations, independent of current B12 intakes (P<0.001). Milk and curd (yoghurt) intakes were unrelated to B12 status.

CONCLUSIONS

Meat and fish are important B12 sources in this population. Micronutrient-enriched beverages appear to be important sources in our cohort, but their high sugar content necessitates care in their recommendation. Improving maternal B12 status in pregnancy may improve Indian children's status.