Location: Obesity and Metabolism Research2015 Annual Report
1. Zinc affects lipid synthesis in fat cells. ARS researchers at the Western Human Nutrition Research Center in Davis, California, have shown that mice in which the zinc transporter 7 (Znt7) is knocked out are mildly deficient in zinc, have low body weight gain and decreased body fat accumulation. Also, Znt7 has been shown to have differential effects on fat metabolism and insulin usage. For example, it promotes fat storage via enhanced utilization of insulin in fat lying under the skin, but not fat that surrounds internal organs in the body. Increased fat accumulation under the skin has been shown to have a protective role against insulin resistance, a preclinical phase of type 2 diabetes. Importantly, ARS researchers found that ZnT7 protein expression was induced by the fat cell maturation process which peaks in fully matured fat cells. Low ZnT7 expression affects the signaling pathways that regulate both basal and insulin-stimulated glucose uptake in fat cells, resulting in low glucose uptake and reduced fat accumulation.
2. Development and application of a new marker of vitamin B-12 status, cB12. Markers of vitamin status are important for the accurate determination of deficiencies. There are four traditionally used biomarkers of vitamin B-12 status; plasma B-12, holotranscobalamin, methylmalonic acid and total homocysteine. These markers are usually applied alone or as a ratio with one other, but this often results in an inconsistent classification of people or populations as being vitamin B-12 deficient. ARS researchers at the Western Human Nutrition Research Center, in Davis, California, in collaboration with Aarhus University, developed a new biomarker, cB12, which combines the usual four biomarkers, and have demonstrated its improved performance for detecting metabolomic and neurological responses to vitamin B-12 interventions. This research has produced a new marker of vitamin B12 status which is likely to be used widely in clinical practice, epidemiological status, and nutrition research.
Huang, L., Drake, V.J., Ho, E. 2015. Zinc. Advances in Nutrition. 6:224-226.
Dary, O., Rambelson, Z., Shahab-Ferdows, S., Dror, D., Allen, L.H., Carriquiry, A., Salman, R. 2014. Predicted efficacy of the Palestinian wheat flour fortification program: complementary analysis of biochemical and dietary data. Public Health Nutrition. 18:1950-1957.
Siddiqua, T.J., Ahmad, S.M., Ahsan, K.B., Rashid, M., Roy, A., Rahman, S.M., Shahab-Ferdows, S., Hampel, D., Ahmed, T., Allen, L.H., Raqib, R. 2015. Vitamin B12 supplementation during pregnancy and postpartum improves B12 status of both mothers and infants but vaccine response in mothers only: a randomized clinical trial in Bangladesh. European Journal of Nutrition. 54:1-13.
Fedosov, S.N., Britio, A., Miller, J.W., Green, R., Allen, L.H. 2015. Combined indicator of vitamin B12 status: modification for missing biomarkers and folate status, and recommendations for revised cut-points. Clinical Chemistry. 53(8):1215-1225.
Fialkowski, M.K., Ettienne-Gittens, R., Shvetsov, Y.B., Rivera, R.L., Van Loan, M.D., Savaiano, D.A., Boushey, C.J. 2014. Ethnicity and acculturation: do they predict weight status in a longitudinal study among Asain, Hispanic, and non-Hispanic White early adolescent females? Adolescent Health. 5:1-7.