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United States Department of Agriculture

Agricultural Research Service

Research Project: Mineral and Vitamin Interventions for At-risk Populations

Location: Obesity and Metabolism Research Unit

Title: Vitamin B-12 supplementation of rural Mexican women changes biochemical B-12 status indicators but does not affect hematology or a bone turnover marker

Authors
item Shahab-Ferdows, Setti
item Anaya-Loyola, Miriam -
item Vergara-Castaneda, Hayde -
item Rosado, Jorge L -
item Keyes, William
item Newman, John
item Miller, Joshua -
item Allen, Lindsay

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 19, 2012
Publication Date: June 12, 5012
Citation: Shahab-Ferdows, S., Anaya-Loyola, M.A., Vergara-Castaneda, H., Rosado, J., Keyes, W.R., Newman, J.W., Miller, J., Allen, L.H. 5012. Vitamin B-12 supplementation of rural Mexican women changes biochemical B-12 status indicators but does not affect hematology or a bone turnover marker. Journal of Nutrition. vol. 142, no. 10, 1881-1887.

Interpretive Summary: Based on the high prevalence of low serum vitamin B-12 concentrations and low dietary intake of the vitamin in Latin American studies including research in Mexico, it appears that vitamin B-12 deficiency is common. Whether this is associated with adverse effects on human function is unknown. To evaluate this question, a randomized controlled trial was conducted in rural Queretaro, Mexico. Women age 20-59 y (n=132) were assigned at baseline to deficient, marginal and adequate status groups based on their serum vitamin B-12 (75-148, 149-220, and >220 pmol/L, respectively). Those with serum B-12 <75 pmol/L (6%) were all treated with B-12 and not studied further. Women in each group were then randomized to receive vitamin B-12 (a 1 mg intramuscular dose followed by 500 mg supplements for 3 mo, n=70) or a placebo (n=62). Blood samples were collected at baseline and after the 3 mo intervention. At baseline 11% of the women were deficient and 22% had marginal status. Other biomarkers of B-12 deficiency at baseline were holoTC (low in 23%), methylmalonic acid (elevated in 21%) and homocysteine (elevated in 31%). All three biomarkers were correlated with serum B-12. Supplementation with vitamin B-12 brought all biomarker values to normal except for homocysteine which remained elevated in 21%, possibly due to other B vitamin deficiencies. Supplementation did not improve hemoglobin or any other red blood cell parameters, or affect bone turnover as measured by bone specific alkaline phosphatase. We conclude that vitamin B-12 status is poor in these women and that supplementation improved their enzyme function as reflected in normalization of biomarkers, but assessing their hematological status and a bone turnover marker did not reveal other functional abnormalities.

Technical Abstract: Based on the high prevalence of low serum vitamin B-12 concentrations and low dietary intake of the vitamin in Latin American studies including research in Mexico, it appears that vitamin B-12 deficiency is common. Whether this is associated with adverse effects on human function is unknown. To evaluate this question, a randomized controlled trial was conducted in rural Queretaro, Mexico. Women age 20-59 y (n=132) were assigned at baseline to deficient, marginal and adequate status groups based on their serum vitamin B-12 (75-148, 149-220, and >220 pmol/L, respectively). Those with serum B-12 <75 pmol/L (6%) were all treated with B-12 and not studied further. Women in each group were then randomized to receive vitamin B-12 (a 1 mg intramuscular dose followed by 500 mg supplements for 3 mo, n=70) or a placebo (n=62). Blood samples were collected at baseline and after the 3 mo intervention. At baseline 11% of the women were deficient and 22% had marginal status. Other biomarkers of B-12 deficiency at baseline were holoTC (low in 23%), methylmalonic acid (elevated in 21%) and homocysteine (elevated in 31%). All three biomarkers were correlated with serum B-12. Supplementation with vitamin B-12 brought all biomarker values to normal except for homocysteine which remained elevated in 21%, possibly due to other B vitamin deficiencies. Supplementation did not improve hemoglobin or any other red blood cell parameters, or affect bone turnover as measured by bone specific alkaline phosphatase. We conclude that vitamin B-12 status is poor in these women and that supplementation improved their enzyme function as reflected in normalization of biomarkers, but assessing their hematological status and a bone turnover marker did not reveal other functional abnormalities.

Last Modified: 9/21/2014
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