RESUMO
Background: Adolescents' diets have been overlooked in nutrition information systems, interventions, and policies. The minimum dietary diversity for women (MDD-W) indicator has been validated to signal greater micronutrient adequacy among nonpregnant women from low- and middle-income countries, but there is limited evidence for valid food group thresholds among boys or nonpregnant nonlactating girls. Objective: To define a food group threshold that reflects minimum dietary diversity for adolescents. Methods: This multicountry study evaluated the test characteristics of a 10-point food group diversity score (FGDS)-underlying MDD-W-and food group thresholds to predict the micronutrient adequacy of diets from single 24-h recalls or food diaries (24-HRs) among 83,935 adolescents aged 10-19 y and repeated 24-HRs among 75,480 adolescents from upper-middle and high-income countries. Results: FGDS was lowest among adolescents in lower-middle countries (3.5 ± 1.1) and greatest in high-income countries (5.4 ± 1.3 points). Using single 24-HRs, 1-point increments in FGDS performed identically to predict a higher mean adequacy ratio among boys and girls (5.1 percentage points; 95% confidence interval: 5.0, 5.2; P < 0.001). MDD-W (i.e., ≥5 food groups) performed well in predicting a mean adequacy ratio of >0.60 among adolescents from upper-middle and high-income countries, whereas a ≥4 food group cutoff showed a superior balance between sensitivity, specificity, and percentage correctly classified in low (only girls) and lower-middle-income countries (boys and girls). In contrast, using repeated 24-HRs, the mean probability of adequacy levels among adolescents were too high and homogeneous (i.e., all mean probability of adequacies > 0.60) to define an optimal food group threshold. Conclusions: MDD-W can be extended to boys and girls aged 10-19 y from upper-middle and high-income countries. Furthermore, an adapted indicator using a ≥4 food group threshold signals higher micronutrient adequacy in low and lower-middle-income countries. Food group cutoffs to predict the micronutrient adequacy of usual intakes should be validated using repeated 24-HRs in populations where a lower proportion of adolescents meet mean dietary requirements.
RESUMO
Plants growing on heavy metal (HM)-polluted soils show toxicity symptoms, such as chlorosis and growth reduction, and undergo oxidative stress due to the formation of reactive oxygen species (ROS). Plants overcome oxidative stress by producing a wide range of antioxidant molecules, such as polyphenols and flavonoids. The aim of the present work was to study the accumulation of these molecules in response to increasing concentrations of Cd, Cr, Cu, Ni, Pb and Zn and to assess whether they can be used as a tool in assessing metal-related stress in Polygonum aviculare and Senecio vulgaris. On average, P. aviculare shoots accumulated lower amounts of metals than S. vulgaris shoots. The uptake of all six elements was correlated and proportional to their concentration in the nutrient solution (ρ > 0.9), with the bioaccumulation factor (BAF) being >1 for most of them. The present research demonstrated that 82% of the samples showed a good correlation (|ρ| > 0.5) between the level of polyphenols, flavonoids and antioxidant activity and the metal concentration in plant shoots, confirming that the metal stress level and production of phenolic compounds having antioxidant activity were strictly connected. Nonetheless, the mere quantification of these molecules cannot identify the type of metal that caused the oxidative stress, neither determine the concentration of the stressors. The five tested populations of each species did not show any specific adaptation to the environment of origin.
