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Objectives

The interests of the Micronutrient Research Group involve understanding the bioavailability of micronutrients, establishing nutrient biomarkers and developing low cost high impact strategies to control micronutrient deficiency in population. We address these issues through integrated research approach involving basic, clinical and programmatic research. We carry out cutting-edge research to revise the micronutrient requirements and recommended dietary allowances for Indians on a regular and continuous basis. The current research areas of the division are (1) understanding the molecular mechanisms of micronutrient absorption, metabolism and interactions of iron and zinc (2) to accurately measure the bioavailability of iron and zinc from habitual meals of various regions of the country in vulnerable segments of the population using state-of-the art techniques of stable isotopes (3) to develop biomarkers of micronutrient status and (4) to develop innovative food fortification strategies.

Research achievements

Nutrient Bio-availability

• Evidence for the possible sequence of intestinal transfer of iron through transferrin receptor and ferritin in human intestine and experimental models has been obtained.


• Demonstrated that iron deficient intestine is more prone to oxidative stress during iron supplementation in experimental models. Further studies demonstrated that iron induced oxidative stress during supplementation can be abrogated by preconditioning with antioxidant vitamins.


• A state-of-the art in vitro human intestinal cell line model (Caco2 cell) for testing of micronutrient bioavailability has been established.


• Plant ferritin iron bioavailability has been shown to be similar to that of typical-non heme iron absorption and that ferritin is subjected to gastric pH induced quaternary and secondary structural perturbations and release of iron from its core.


• Studies so far carried out in experimental model systems suggest that iron and zinc negatively interact with each other during absorption when supplemented together. The extent of these interactions is minimal when both of these nutrients are supplemented at a molar ratio of 1:< 1 of iron to zinc. Concurrent administration of iron and zinc rather than iron alone was shown to maintain functional integrity of intestine during oral iron repletion. Further, molecular mechanisms of cytoprotection by zinc during oxidative stress induced iron signaling have been obtained.


• Demonstrated that enterocyte zinc status has profound influence on the iron absorption and its interaction with zinc, which appears to be through the zinc dependent induction of iron transport protein, DMT-1.


• For the first time we have demonstrated that polyphenol rich beverages increases zinc uptake in intestinal cells.


• A factor having ferric reductase activity in human milk which can enhance bioavailability of iron has been identified.

Biomarkers

• Developed and operationalized an indigenous ELISA method for serum ferritin as a sensitive indicator of iron status and as a surrogate marker of iron bioavailability in Caco2 cells.


• A National Facility for Dried Blood Spot Technology for Vitamin A estimation and its contribution in assessing the extent of sub clinical vitamin A deficiency in children in different NNMB states in the country.

National Programmes

• The technology of double fortification of salt with iron and iodine has undergone extensive field testing and is expected to find a place in the National Program.


• The technology of fortification of whole-wheat flour (atta) with iron, folic acid and its translation to fortify and supply wheat flour through fair price shop in the state of Andhra Pradesh on a pilot scale by the AP State civil supplies department.


• Improvement in iron stores as a result of regular consumption of iron fortified rice has been shown and provides important leads for translating this technology among the rice eating population in the country.


• The beneficial impact of consuming micronutirent-fortified beverage on the micronutrient status, growth, school performance and bone health of school children.

Present Research Activities

RO3 grant (5/4/2010): Indo-US collaborative programme on MCHR on “Enhancing dietary iron and zinc bioavailability in Indian Children collaborator. Prof Steven Abrams,CNRC Baylor College of Medicine.

DBT’s India Crop Biofortification Network “Establishment of screening facility for iron and zinc bioavailability using Caco2 cell line.

DBT: USA, Bangalore-NIN collaborative project: Development of QTL and MAS breeding to develop high zinc pigeon pea (Cajanus cajan).

DST Fast Track: Purification and characterization of human milk factor that enhances iron bioavailability from human milk.

ICMR: NFI-NIN collaborative project: ICMR Advanced Centre (2) for Nutrition Research.

NIN- University of Maryland Baltimore and MI Collaborative project: Innovative strategies to promote early child development among low-income rural infants and preschoolers in India through multiple micronutrient fortification and early learning opportunities.