Screening for inadequate dietary vitamin B-12 intake in South Asian women using a nutrient-specific, semi-quantitative food frequency questionnaire.

BACKGROUND AND

OBJECTIVES

A high prevalence of vitamin B-12 (B-12) deficiency among young women of South Asian origin predisposes to significant health risks for these women and their future offspring. Vegetarian or low-meat based dietary practices contribute to B-12 deficiency. This study validated a nutrient-specific, semi-quantitative food frequency questionnaire (B12FFQ), developed to estimate dietary B-12 intake in South Asian women.

METHODS AND STUDY

DESIGN

The B12FFQ was developed, then tested in 60 apparently healthy South Asian women aged 18-50 years, living in Auckland, New Zealand. Participants recalled the frequency and quantity of vitamin B-12-containing foods consumed in the preceding three months. Pearson's correlations measured the associations between dietary B-12 intake and B-12 biomarkers (serum B-12 and holotranscobalamin [holoTC]). Likelihood of B12 insufficiency was calculated for vegetarian and non-vegetarian dietary practices.

RESULTS

The B12FFQ was a valid measure of dietary B-12 intake - supported by moderate positive associations with serum B-12 (r=0.50, p<0.001, 95% CI [0.28, 0.67]) and holoTC (r=0.55, p<0.001, 95% CI [0.34, 0.71]). A dietary B-12 intake of less than 2.4 µg/day increased the likelihood of serum B-12 (X2 (1)=11.79, p=0.001) or holoTC (X2 (1)=6.33, p=0.012) insufficiency. A dietary B-12 intake of less than the recommended dietary allowance (2.4 µg/day), occurred in 61% (n=20/33) of participants with vegetarian and 22% (n=6/27) with non- vegetarian dietary practices.

CONCLUSIONS

The B12FFQ provides a valid estimate of dietary B-12 intake. This easily administered food frequency questionnaire has the potential to identify low dietary B-12 intake as a contributor to B-12 depletion or deficiency.