Heavy metals in Niger seed oil

Provisional scaffold. This page was created automatically on 2026-06-02 so that an ingested source could route to it. Aliases, category, and the contamination profile have not yet been populated. Content below is minimal until a synthesis pass consolidates the literature for this ingredient.

Reason: June 2 manual-fetch edible-oil source reports Ethiopian nuog/niger seed oil metal concentrations

Triggering source: Physico-Chemical Characteristics and Level of Some Selected Metal in Edible Oils

Literature scope

Reported measurements from source notes are below. No typical or upper-tail value is calculated here, and no certification limit is stated. The contamination profile in the page frontmatter is unchanged.

Reported measurements

The 2016 Ethiopia note reports two industrially processed Ethiopian niger seed oil samples, labeled here as sample A and sample B, in mg/L in the diluted oil digest. Sample A was sodium 3.80 +/- 0.100 mg/L, potassium 8.10 +/- 0.200 mg/L, copper 0.86 +/- 0.003 mg/L, zinc 1.19 +/- 0.160 mg/L, and iron 7.32 +/- 0.530 mg/L. Sample B was sodium 4.13 +/- 0.153 mg/L, potassium 10.30 +/- 0.200 mg/L, copper 0.42 +/- 0.005 mg/L, zinc 1.47 +/- 0.567 mg/L, and iron 6.08 +/- 0.818 mg/L. Method detection limits in the note are sodium 0.0306 mg/L, potassium 0.0191 mg/L, copper 0.0246 mg/L, zinc 0.0151 mg/L, and iron 0.0283 mg/L. Limits of quantitation are sodium 0.306 mg/L, potassium 0.191 mg/L, copper 0.246 mg/L, zinc 0.033 mg/L, and iron 0.075 mg/L. The note states that the metal values are reported in mg/L in the diluted oil digest solution. This page does not convert them to mg/kg of oil. Palm-oil rows are not niger seed oil and are not repeated here. The note does not report lead, cadmium, arsenic, mercury, nickel, aluminum, chromium, or tin in these oils. Physico-Chemical Characteristics and Level of Some Selected Metal in Edible Oils

Niger seed oil and gut studies of iron, zinc, and copper

The metals this section can speak to for niger seed oil are iron, zinc, and copper. The records are a review of iron status, experimental zinc diets, and an occupational trial that lowered blood copper after a probiotic yogurt. An oil mill should treat residual metal chemistry and gut claims as separate. Oil microbiota, if monitored, would be a spoilage or refining question and is not what these papers measured.

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

None of the studies used niger seed, Guizotia, or a vegetable oil. The iron review omits sample sizes. Zinc doses are mouse diets. Copper changes were measured in occupationally exposed adults. The section is thin relative to a toxic-metal page because that is what these sources support.

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. Physico-Chemical Characteristics and Level of Some Selected Metal in Edible OilsBereket Tesfaye and Alemayehu Abebaw · Advances in Chemistry · 2016 · doi.org/10.1155/2016/3480329Peer-reviewed
2. 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
3. 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
4. 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

Sources

Source records associated with this topic. Inclusion does not establish that every finding applies to this product or ingredient. References above identify works cited in the text.

Update history

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