Bioaccessibility of trace elements and chromium speciation in commonly consumed cereals and pulses

Cr and Mn total, accessible species, and protein-fraction contents in plants used for traditional anti-diabetes treatment

BACKGROUND

Our survey has found eleven plants that have being consumed for traditional treatment of diabetes mellitus, particularly in Saudi Arabia and generally in many countries across the world. The literature reported about trace elements such as Cr and Mn positively affecting diabetes mellitus. The aim of this work is to determine the total, accessible element species, and protein-fraction contents of Cr and Mn in the edible parts of those plants.

METHODS

The total contents of Mn were determined by inductively coupled plasma-optical emission spectrometry (ICP-OES), while the total contents of Cr was determined by ICP-sector field (sf)-mass spectrometry (MS) due to lower concentration. The protein-fraction contents were determined in accessible element species by size-exclusion chromatography (SEC)-ICP-MS.

RESULTS AND DISCUSSION

The separation was successfully carried out to quantify Cr and Mn bound up to 11 protein fractions. The examined plants recorded wide ranges of total contents (Cr 44.7-1880.0 μg/kg and Mn 3.7-59.0 mg/kg) and accessible element species contents (Cr 0.93-29.40 μg/kg and Mn 0.82-35.85 mg/kg). Also wide ranges of percentages of accessible element species contents to total contents of Cr (0.65-4.21%) and Mn (5.43-68.42%) were obtained. The hazardous indices of both trace elements Cr and Mn for all examined plants consumed by both children and adults were all < 1, indicating no probability of health risk to occur. Moreover, Cr as carcinogen element reported no probability of cancer risk to occur from the consumption of all examined plants. Irrespective of plant species, Cr was quantified in all SEC fractions (mainly protein fractions), with the exception of 1.9-3.7 kDa, while Mn was quantified in all SEC fractions with the exception of 100-120 and 1.3-3.7 kDa. Nevertheless, the majority of accessible Cr species contents bound to the 10-14 and 0.05-0.40 kDa fractions, while that of Mn bound to 0.05-0.40 kDa fraction. To gather, the benefits of specific plant species in terms of accessible Cr and Mn species contents, in addition to accessible Zn species contents reported in our previous study, Haloxylon Salicornicum, Olea Europaea Momordica and Charantia are recommended to be consumed for traditionally controlling T2DM.

Variability of chromium bioaccessibility and speciation in vegetables: The influence of in vitro methods, gut microbiota and vegetable species

There is limited research concentrating on the effects of gut microbiota on the bioaccessibility and speciation of chromium (Cr) in vegetables. In this study, the physiologically based extraction test (PBET) and the unified BARGE method (UBM), were combined with the simulator of human intestinal microbial ecosystems (SHIME) to determine the bioaccessibility and speciation of Cr from vegetables. The results showed that the Cr bioaccessibility was the highest in the gastric phase. The Cr bioaccessibility from the water spinach was the highest, and was 1.6-3.4 and 1.1-1.8 times that of leaf lettuce and celery, respectively. The Cr bioaccessibilities of the UBM method were slightly greater than those of the PBET method. Additionally, the gut microbiota increased the Cr bioaccessibility and reduced more toxic Cr(VI) to less toxic Cr(III) from vegetables. Therefore, our study reveals the possible health risks of consuming Cr-contaminated vegetables based on the bioaccessibility and speciation of Cr.

The health hazards of potentially toxic metals in the daily diets of adults and children from a mining and smelting region (Hezhang County) in southwestern China

Toxic metals accumulated in the human body are predominantly absorbed by the digestive tract in non-occupationally exposed populations. In the current study, we collected plowed soil samples, and investigated the varied food compositions in a mining and smelting area in southwestern China, to measure the concentrations of ten potentially toxic metals-As, Ba, Cd, Cr, Cu, Mn, Ni, Pb, Sr, and Zn. We collected information on the daily intakes of these metals to assess the health risks associated with their exposure among children and adults. The urine concentrations of the metals were also measured to obtain data on the amounts present in the body. The results showed that the hazard indexes (HIs) of As, Ba, Cd, Cr, Ni, Pb, and Sr were all larger than 1, for both adults and children; the Zn and Cu values were comparatively higher in children. The intake of staple foods of the region posed the greatest health risk, while drinking water only posed risks clearly associated with As exposure. The urine samples of local residents contained larger amounts of As, Cd, Cr, Cu, Mn, Ni, Pb, and Zn, confirming the hazards in the health risk assessment. Obvious differences in the urine metal concentrations between men and women were confirmed. In conclusion, higher concentrations of metals in the surface soil and rain water were the predominant cause of elevated exposure through home-grown crops and produce to accumulate in local residents' bodies.