Dietary inadequacies overestimate the blood deficiencies of magnesium, zinc, and vitamins A, C, E, and D among residents of Sao Paulo

Abstract

Background & aims: We aimed to estimate the prevalence of the inadequate intake and status of magnesium, zinc, and vitamins A, C, E, and D and identify factors associated with micronutrient deficiency in serum/plasma among residents of São Paulo, Brazil.

Methods: Data from 824 individuals aged ≥14 years were obtained from the 2015 ISA-Nutrition, a population-based, cross-sectional survey. Dietary and supplement intakes were assessed using two 24-h dietary recalls, and the micronutrient inadequacies were estimated using the National Cancer Institute method. Micronutrient status was measured in serum or plasma, and deficiency was established according to the lower limit of the reference values. Receiver operating characteristic curve analysis was used to identify the effect of intake on the micronutrient status in serum/plasma. Logistic regression analysis was applied to assess the association between micronutrient status and individual characteristics.

Results: More than 80% of the population had an inadequate dietary intake of magnesium, vitamin E, and vitamin D. Males had a high prevalence of inadequate dietary intake of vitamin A and zinc. A high-to-moderate prevalence of inadequate vitamin C intake was observed. Vitamin D was the only nutrient with a deficient status comparable to its dietary inadequacy. The other nutrients demonstrated a lower deficiency prevalence compared to dietary inadequacy, and vitamin A demonstrated the lowest prevalence of deficiency in plasma. Generally, dietary intake showed a non-notable association with micronutrient deficiency in serum/plasma. Individuals with fasting glucose concentrations ≥100 mg/dL and those using diuretic drugs had a higher risk of serum magnesium deficiency. Those using lipid-lowering drugs and those with high plasma adiponectin concentrations had a higher risk of serum zinc deficiency. Individuals who smoked and those with hypertension showed a higher risk of plasma vitamin C deficiency. Individuals with average leptin concentrations had a higher risk of plasma vitamin E deficiency. Finally, those with sufficient leisure-time physical activity had a lower risk of serum vitamin D deficiency.

Conclusions: Residents of the urban areas of São Paulo demonstrated substantially inadequate intakes of most of the assessed micronutrients; however, micronutrient deficiency in serum/plasma was not associated with dietary inadequacy, and it usually demonstrated a lower prevalence than dietary indicators. Thus, using micronutrient intake to determine the serum/plasma profile should be done with caution. The status of the micronutrients varied according to individual characteristics, indicating the interplay of complex mechanisms underlying micronutrient balance.

Keywords: Diet assessment; Mineral; Nutritional biomarkers; Nutritional deficiency; Vitamin.