Trace and Macro Elements Concentrations in Selected Fresh Fruits, Vegetables, Herbs, and Processed Foods in North Carolina, USA

Abstract

Fresh fruits, vegetables, herbs, and processed foods continue to be the major sources of essential trace elements in humans’ diet required for proper body development. However, food products can potentially be contaminated by toxic heavy metals (HMs) from environmental contamination or industrial food processing. The deleterious health implications of essential trace and macro elements’ deficiency and toxic consequences of HMs in humans necessitate proactive monitoring of the essential trace elements and HMs concentrations in the humans diet to ensure public health safety. Accordingly, this study investigated a comparative analysis of essential elements and potential toxic HMs concentration in food products in the Greensboro metropolis, North Carolina, USA. A total of 49 food samples comprising of 16 difference fresh fruits, 17 fresh vegetables, 4 herbs, and 12 processed foods were purchased from local grocery stores and analyzed for iron (Fe), calcium (Ca), magnesium (Mg), nickel (Ni), zinc (Zn), copper (Cu), lead (Pb), cadmium (Cd), and chromium (Cr) by the use of flame atomic absorption spectrometry (FAAS). The concentrations of elements were subjected to a regression analysis to further gain insight of the inter-element association in the food samples. The results of the study showed high variability in the concentrations of elements in the fresh fruits, vegetables, herbs, and processed foods. The overall average concentrations of Ca (1501 μg/g), Mg (186.5 μg/g), Fe (55.8 μg/g), Zn (22.2 μg/g), Pb (10.2 μg/g), Cu (5.8 μg/g), Cr (<0.1 μg/g), Cd (<0.1 μg/g), and Ni (<0.04 μg/g) were obtained in all food samples categories. The elements concentrations were generally poorly correlated in the food samples. However, a strong inter-element association between Cu and Fe concentration (R2 = 1.000) and a weak association between Ca and Fe (R2 = 0.5609) were found in the food samples. A survey questionnaire was administered to 396 participants in the Greensboro metropolis to evaluate the food consumption pattern and a daily/weekly dietary estimate intake of vegetables, fruits, herbs and processed foods. The results of the food survey analysis showed that the amount of vegetables, fruits, herbs, and processed foods dietary intake varied widely. In general, the participants consumed more processed foods than vegetables, fruits, and herb foods. The low dietary intake of vegetables, fruits, herbs suggests that most participants may be obtaining insufficient essential trace elements and other vital nutrients necessary for normal growth and body development in their diet.