Heavy metals in Popcorn

Overview

This provisional ingredient page records source-specific measurements for popcorn. Its population contamination profile has not been synthesized. See Ingredients for the ingredient inventory.

Heavy metal contamination profile

The profile fields remain pending until an evidence synthesis supports a population estimate. Source observations are listed separately below.

Reported measurements from source notes are below. The contamination profile on this page is still pending. No typical or upper-tail value is calculated here, and no certification limit is stated.

Reported measurements

The 2017 note reports popcorn from five shops in an Addis Ababa open market, pooled, on a dry-weight basis, from Table 1. Potassium was 1293 ± 233 mg/kg, sodium 148 ± 3 mg/kg, magnesium 387 ± 11 mg/kg, calcium 97.9 ± 4.2 mg/kg, total chromium 0.68 ± 0.09 mg/kg, manganese 6.17 ± 0.18 mg/kg, iron 9.5 ± 2.1 mg/kg, cobalt 1.41 ± 0.16 mg/kg, copper 0.09 ± 0.007 mg/kg, zinc 88.3 ± 9.7 mg/kg, and lead 0.94 ± 0.29 mg/kg. Cadmium and nickel were not measured as a concentration (below detection, and the table does not print a numeric detection limit). Cornflake means are not popcorn and are not repeated here. The note’s sample count of 8 is five popcorn shops plus three cornflake packs. Table 8 estimates popcorn intake at 4.7 µg lead per day at 5 g per day. That figure is an intake estimate, not a popcorn concentration. Table 8 prints the lead tolerable upper limit as 25 µg/kg body weight per day. The note says the underlying JECFA reference is the withdrawn provisional tolerable weekly intake of 25 µg/kg body weight per week. This page repeats both and does not choose one. Those figures are the authors’ comparators, not popcorn concentrations. A cereal-ceiling comparison added on the source page is a wiki-side crosswalk, not the paper’s comparison, and is not repeated here. Assessment of essential and non-essential metals in popcorn and cornflake commercially available in Ethiopia

Popcorn and gut studies of lead, hexavalent chromium, iron, zinc, and copper

Popcorn is a popped grain snack. The studies below are infant tooth lead, childhood blood lead, hexavalent chromium gavage, an iron review, experimental zinc diets, and an occupational yogurt trial. Popping oil and seasoning are not factors in these papers. A snack specification should not treat a gavage dose as a popcorn concentration.

Sitarik et al. 2020 measured tooth lead and stool microbiota at 1 month and 6 months in 146 maternal-child pairs in the Detroit-area WHEALS cohort. In utero tooth lead was associated with fungal community composition at 1 month. Lead was not associated with overall bacterial community structure. Taxon-level bacterial shifts were higher Collinsella at 1 month, higher Bilophila at 6 months, and lower Bacteroides. The direction is lead exposure toward microbiota composition. Tooth lead is a biomarker, not a concentration in this ingredient.

Eggers et al. 2023, per WikiBiome source summary, DOI 10.3389/fmicb.2023.1193919, followed 123 children in the Mexico City PROGRESS cohort. Maternal blood lead means were 33.6 µg/L in the second trimester and 34.9 µg/L in the third. Stool metagenomes at ages 9 to 11 showed lower Bacteroides caccae with lead exposure. Weighted quantile sum regression gave a negative overall mixture effect (beta = -0.17) in both trimesters. The direction is prenatal lead toward the childhood gut microbiota. The summary does not support a lead concentration in food.

Mu et al. 2023 gavaged mice with potassium dichromate at 75 mg/kg for 29 days (n = 60 across three groups). Hexavalent chromium lowered Chao1 diversity from 170.75 ± 15.79 to 87.00 ± 9.55 (p = 0.00029) and Shannon diversity from 4.64 ± 0.68 to 2.64 ± 0.64 (p = 0.0055). Escherichia_Shigella rose from 10.71 percent to 57.75 percent. Seaweed polysaccharide at 200 mg/kg partly reversed the shift. The direction is hexavalent chromium toward gut microbiota. The dose is a gavage dose. It is not a total-chromium concentration in food.

Richardson et al. 2018, per WikiBiome source summary, DOI 10.1038/s41598-018-24931-w, gavaged Sprague-Dawley rats for 5 days with sodium arsenite, cadmium chloride, sodium dichromate, cobalt chloride, or nickel chloride, 5 rats per cohort. The note does not print the milligram doses. Observed OTUs and Shannon diversity were lower for arsenic, chromium, and nickel (p < 0.05). Differential genera numbered 37 for nickel, 17 for arsenic, 5 for cadmium, and 10 for chromium. Sodium dichromate is a hexavalent chromium salt, so the chromium arm is not a total-chromium result. The direction is short oral exposure toward the rat gut microbiota.

Bao et al. 2024, per WikiBiome source summary, DOI 10.3390/ijms25020727, is a review of iron homeostasis and gut microbiota. The note states that iron deficiency anemia was associated with lower Bacillota and higher Bacteroidota, Pseudomonadota, and Patescibacteria, and that iron-deficient women had lower fecal Lactobacillus. It also states that iron supplementation increased Enterobacteriaceae and decreased Lactobacillus in infants, and that iron fortification increased Bacteroidetes in African children. Sample sizes are not in the note. The direction summarized is iron status toward gut microbiota. The review does not test this ingredient.

Chen et al. 2021, per WikiBiome source summary, DOI 10.1128/Spectrum.00483-21, fed C57BL/6 mice diets with 0, 30, 150, or 600 mg/kg zinc for 4 weeks and for 8 weeks. A 4-week diet with no added zinc increased Proteobacteria and Desulfovibrio. An 8-week diet with 150 mg/kg zinc suppressed total short-chain fatty acids, butyric acid, acetic acid, and short-chain-fatty-acid-producing genera. A 600 mg/kg diet decreased Shannon diversity. The mouse count is not in the note. The direction is dietary zinc status toward cecal microbiota. The diets are experimental, not this ingredient.

Feng et al. 2022, per WikiBiome source summary, DOI 10.1038/s41522-022-00326-8, randomized 152 occupationally exposed workers in Pakistan, 76 in each arm, to yogurt with Pediococcus acidilactici GR-1 or to conventional yogurt for 12 weeks. In the probiotic arm, blood copper fell 34.45 percent, from 1,246 ± 20.7 to 817 ± 145.1 µg/L (p < 0.0001), and fecal copper rose. The direction is a microbiota intervention toward copper body burden. The workers were occupationally exposed. The trial is not a test of copper in this ingredient.

Study table

What remains uncertain

No study cited here fed popcorn. Chromium in both gavage studies was a hexavalent salt, which is not total chromium in a popped grain. Iron evidence is a review. Zinc diets are experimental. The yogurt trial enrolled occupationally exposed workers.

FDA TDS FY2018–FY2020 source observations

FDA measured the prepared foods named below. Each row describes that food and preparation, not every form of this ingredient. Values are µg/kg (ppb) on the FDA sample basis. ND means not detected; it is not a measured zero. Reporting limits can vary between composites. FY2018-FY2020 TDS Elements Analytical Results

References

Works cited in this page’s text, in first-appearance order. See Sources for this page’s source inventory. Each title links to a source record with bibliographic details, reported findings, and document provenance.

1. Assessment of essential and non-essential metals in popcorn and cornflake commercially available in EthiopiaAbebe A, Chandravanshi BS, and Debebe A · Chemistry International 3(3):268-276 · 2017 · www.bosaljournals.comPeer-reviewed
2. Fetal and early postnatal lead exposure measured in teeth associates with infant gut microbiotaSitarik AR, Arora M, Austin C, Bielak LF, Eggers S, Johnson CC, et al. · Environment International · 2020 · doi.org/10.1016/j.envint.2020.106062Peer-reviewed
3. Prenatal lead exposure is negatively associated with the gut microbiome in childhoodEggers S, Midya V, Bixby M, Gennings C, Torres-Olascoaga LA, Walker RW, et al. · Frontiers in Microbiology · 2023 · doi.org/10.3389/fmicb.2023.1193919Peer-reviewed
4. Seaweed polysaccharide relieves hexavalent chromium-induced gut microbial homeostasisMu J, Guo Z, Wang X, Wang X, Fu Y, Li X, et al. · Frontiers in Microbiology · 2023 · doi.org/10.3389/fmicb.2022.1100988Peer-reviewed
5. Exposure to toxic metals triggers unique responses from the rat gut microbiotaRichardson JB, Dancy BCR, Horton CL, Lee YS, Madejczyk MS, Xu Z, et al. · Scientific Reports · 2018 · doi.org/10.1038/s41598-018-24931-wPeer-reviewed
6. Mechanism of Iron Ion Homeostasis in Intestinal Immunity and Gut Microbiota RemodelingBao H, Wang Y, Xiong H, Xia Y, Cui Z, and Liu L · International Journal of Molecular Sciences · 2024 · doi.org/10.3390/ijms25020727Peer-reviewed
7. Effect of long-term and short-term imbalanced zinc manipulation on gut microbiota and screening for microbial markers sensitive to zinc statusChen L, Wang Z, Wang P, Yu X, Ding H, Wang Z, et al. · Microbiology Spectrum · 2021 · doi.org/10.1128/Spectrum.00483-21Peer-reviewed
8. Human supplementation with Pediococcus acidilactici GR-1 decreases heavy metal levels through modifying the gut microbiota and metabolomeFeng P, Yang J, Zhao S, Ling Z, Han R, Wu Y, et al. · npj Biofilms and Microbiomes · 2022 · doi.org/10.1038/s41522-022-00326-8Peer-reviewed
9. FY2018-FY2020 TDS Elements Analytical ResultsU.S. Food and Drug Administration · FDA Total Diet Study · 2022 · www.fda.govDataset

Sources

Sources catalogued for this page. The last column says how each source is used here.

Update history

No substantive edit history is available in this build. The full commit record is available in git.