41). Two of the functional indicators of zinc, namely taste acuity and cognitive testing, have been used to assess zinc status in childhood (40, 42). The exact mechanisms are not clear but it appears that zinc is essential for neurogenesis, neuronal migration, synaptogenesis, and its deficiency could interfere with neurotransmission and subsequent neuropsychological behaviour (43). Supplementation of zinc in US school children showed significant improve- ment in cognitive performance (44). However, a study carried out in China has reported supplementation of zinc with micronutrients was more effective than zinc alone in enhancement of neuropsychological performance and growth in children (45). In school children, the data are controversial, but evidence of improved neuropsychologi- cal function has been associated with zinc supplementa- tion (43). In particular, the effect on cognitive performance in response to improved zinc nutrition is critical, given that zinc deficiency is common in both developing and devel- oped countries (46). The sense of taste is mediated through the salivary zinc-dependent polypeptide, gustin. Low salivary zinc concentration leads to a reduction of taste and reduced appetite (47). In young women, it has been reported that the ability to correctly discriminate salt concentrations shows a significant positive correlation with plasma zinc (48). In a cross-sectional study, children with low hair zinc levels were found to have higher median recognition threshold for salt than those with normal hair zinc levels (40). Such studies need to be done in adolescents. Overall, the literature review suggests that: (a) micro- nutrient deficiencies are widespread in adolescents all over the world. Yet, information on micronutrient status, in particular of zinc status in Indian adolescents is lacking; (b) inadequate dietary intake of absorbable zinc is the primary cause of zinc deficiency, and dietary strategies are needed to improve the bio-available zinc intake of adolescents, especially that of girls; (c) a simple tool to assess the micronutrient quality of the diets of adolescents is required, which will help in identifying high-risk adolescents; and (d) intervention studies have confirmed the critical importance of adequate zinc nutrition to improve cognitive performance in children. However, little is known about the magnitude of effects of zinc supplementation on cognitive performance in adolescents. Rationale and significance of the study Vitamin and mineral deficiencies adversely affect a third of the world’s population (49), and it is estimated that one in five people worldwide lack sufficient dietary zinc (41). Adolescent girls may be more prone to zinc deficiency because physiological requirements for zinc peak during adolescence at the time of the pubertal growth spurt, which generally occurs in girls between 10 and 15 years (50). Especially, adolescents from developing countries Citation: Glob Health Action 2012, 5: 7353 - DOI: 10.3402/gha.v5i0.7353 Zinc status and its association with health of Indian adolescent such as India are at high risk because of low zinc intakes and poor bioavailability of zinc from vegetarian diets, which leads to low zinc status. In adolescents, a wide range of disturbances occur due to zinc deficiency, including impaired growth, defects in the immune system, dermatitis, diarrhoea, delayed sexual and bone matura- tion, impaired taste acuity and behavioural changes (41). Therefore, more research is required to assess zinc status of Indian adolescent girls. Simple measures such as diet quality index are used to assess adherence to dietary guidelines. To identify micro- nutrient deficiencies in adolescents, in particular that of zinc, a simple tool needs to be devised, which can judge the micronutrient quality of diet. Such an index would be of vital importance for identifying at-risk individuals and targeting the intervention programmes. Guidelines by WHO have recommended food-based approaches to resolve micronutrient deficiencies (49). Moreover, zinc-rich dietary supplement has a potential to revert bad health effects of low zinc status. Therefore, increasing consumption of foods with a high content of absorbable zinc can become a long-term sustainable strategy to overcome zinc deficiency. Considering the enhancers and inhibitors in vegetarian diets (18), low-cost food recipes need to be devised to provide high bio- available zinc. Studies have documented positive effects of zinc supplements in infants and children for morbidity and growth (51). However, research on the beneficial effects of improved zinc nutrition for behaviour and cognitive function in school-age children is critically needed because zinc deficiency continues to be a modern health concern in both developing and developed countries (46, 52). Study objectives The present research aimed to study zinc status and its association with profile of other micronutrients, and to examine the effect of zinc supplementation on functional indices of zinc in adolescent girls. The specific objectives of the study were: (1) To study zinc status and its association with the profile of other micronutrients, cognitive perfor- mance and taste acuity of the adolescent girls. (2) To examine the diet patterns of vegetarian adoles- cent girls for zinc adequacy and devise recipes to improve bio-available zinc intakes. (3) To develop and validate a nutrient quality index to assess micronutrient sufficiency of diets using statistical techniques and bioavailability of micro- nutrients. (4) To examine efficacy of dietary supplementation on blood micronutrient levels and functional indices of zinc. 3 (page number not for citation purpose)