Wheat

Completeness scorecard

Deterministic gap audit — no score is composite, no cell is LLM-judged. Each chip is re-derivable by re-running tools/evidence/build-ingredient-scorecard.mjs. review: residuals and missing data are worked autonomously via data/evidence/ingredient-scorecard-review-flags.csv and wiki/completeness-gaps.md.

Wheat is identified across EFSA Cd 2009 and JECFA 91st 2022 as one of the top population-level dietary cadmium contributors, with the bran and germ fractions carrying higher cadmium than refined endosperm.

Heavy metal contamination profile

Per-analyte snapshot derived from the machine-readable contamination_profile in the frontmatter above. data gap indicates the literature has been reviewed for this commodity-analyte combination and no usable occurrence data was found (a finding, not a placeholder). The Key sources column shows the top 2-3 contributing sources by year and sample size, with numbered wikilink aliases.

Synthesis basis and censoring treatment

The inorganic-arsenic, aluminium, and chromium cells were resynthesized on 2026-06-11. Wheat is reported by sources in two distinct bases: wheat grain or wheat flour as marketed (the form that enters the supply chain) and finished bread or cereal as consumed. Values below the analytical limit of detection or quantification are treated as left-censored, not as measured zeros, and the lower bound of a fully or near-fully censored cell is carried as a numeric zero with the reporting limit stated here in prose. The FDA Total Diet Study FY2018-FY2020 element panel does not speciate inorganic arsenic and does not report aluminium, so the FDA dataset contributes only to the total-chromium cell for the routed wheat foods (white bread, whole wheat bread, cream of wheat).

Inorganic arsenic rests on a single primary speciated source, and its central and 95th-percentile values are a left-censored bound rather than a measured concentration. The UK Food Standards Agency Total Diet Study measured inorganic arsenic separately from total arsenic by hydride-generation ICP-MS and reported every bread and cereal composite below the 12 µg/kg limit of quantification, including white sliced bread, white unsliced bread, brown bread, wholemeal and granary bread, flour, breakfast cereals, other cereal products, pasta, and pizza (Baxter et al. 2015, iAs <0.012 mg/kg in all wheat-matrix rows; the one cereal-group exception, miscellaneous cereals at ~0.013 mg/kg, is above the limit of detection but below the limit of quantification and is treated as semi-quantitative). The cell is therefore carried as a left-censored 0-to-12 µg/kg with the 95th percentile pinned at the 12 µg/kg reporting limit, at low confidence on a single speciated source. Total arsenic in wheat is held distinct from inorganic arsenic and is not used to populate this cell; the elevated total-arsenic readings in wheat grain from arsenic-affected groundwater regions, such as the maximum of 775 µg/kg total arsenic reported for wheat in arsenic-contaminated districts of Bihar (Kumar et al. 2024), and the secondary citation of inorganic arsenic above 200 µg/kg in South Asian wheat grain in a hydroponic mechanism study (Shi et al. 2022), are documented high-arsenic-region strata and are not folded into the speciated central estimate.

Aluminium rests on bread and flour as marketed and is supported by three A-tier sources in agreement on a central concentration of roughly 4,000 to 5,000 µg/kg. The UK Total Diet Study reports aluminium at 4,010 µg/kg in the bread group, with individual bread composites from 2,720 µg/kg (wholemeal and granary) to 5,120 µg/kg (white sliced) and flour at 5,190 µg/kg (Baxter et al. 2015); the EFSA EU-FORA assessment of Polish rye-wheat bread reports an aluminium mean of 4,054 µg/kg with a median of 3,919 and a standard deviation of 1,251 on a fresh-weight basis (Balbo and Wozniak 2022); and the Iranian multi-province bread survey reports an aluminium mean of 4,980 µg/kg at 96 percent detection (Asadi Touranlou et al. 2025, dry-weight basis by ICP-OES). The Mashhad flour-dough-bread triplet study confirms aluminium exceeding the source-cited WHO/FAO comparator in all five city regions on a dry-weight basis (Asadi Touranlou et al. 2025). The 95th percentile of 7,000 µg/kg is set from the upper tail of the Polish bread distribution (mean plus roughly two-and-a-third standard deviations) and the Iranian mean-plus-spread, both of which place the high tail near 7,000 to 8,000 µg/kg. Confidence is held at medium because the contributing values mix a fresh-bread basis (UK, Poland) with a dry-weight basis (Iran) and a dedicated wheat-grain aluminium distribution is not in the corpus. The prior aluminium cell drew its headline anchor from an infant-formula and baby-food survey (Rahati et al. 2026, aluminium mean 1 mg/kg in powdered infant formula), which is a different commodity; that source has been removed from the wheat aluminium synthesis and is retained only on the relevant infant-formula pages.

Chromium is reported as total chromium across the entire wheat corpus; no hexavalent-chromium measurement exists for any wheat matrix, and Cr-VI is never inferred from total chromium. The central estimate is built from the clean-market wheat-grain and bread distribution on a fresh or as-consumed basis, which four sources characterize in agreement. Polish wheat grain measured by graphite-furnace AAS averages 39 µg/kg with a median of 27, a 90th percentile of 79, and a range of less than 2 to 183 µg/kg (Reczajska et al. 2005, n=45 wheat-grain samples; the reporting limit is approximately 1 to 2 µg/kg and the below-limit minimum is carried as a numeric-zero censored floor). Egyptian wheat flour averages 6.8 µg/kg (range 5 to 9) and bread 2.7 µg/kg (range 1 to 4) at a limit of quantification near 0.6 to 1.5 µg/kg (Salahel din et al. 2025). Polish rye-wheat bread averages 134.6 µg/kg with a median of 106 and a standard deviation of 84.5, placing its upper tail near 300 µg/kg (Balbo and Wozniak 2022, n=51). The FDA Total Diet Study reports US wheat foods against a 50 µg/kg reporting limit: white bread is below that limit in 22 of 27 composites with detected values from 54 to 100 µg/kg, whole wheat bread and cream of wheat are fully below the limit and carried as numeric-zero censored floors, and the highest wheat-derived composites are flour tortilla and bran-with-raisins cereal at 200 to 300 µg/kg (FDA 2022). Pooled across these four clean-market sources in their native fresh or as-consumed basis, the ordered distribution sits at a numeric-zero censored floor through its lower half, reaches a 90th percentile near 100 µg/kg, and has a 95th-percentile tail near 300 µg/kg set by the Polish rye-wheat-bread upper tail and the highest FDA wheat-derivative composites. The cell is therefore carried with a typical range of a numeric-zero censored floor to 100 µg/kg and a 95th percentile of 305 µg/kg, an honest upper tail rather than a collapsed single value. Against this clean-market distribution, two strata sit an order of magnitude higher and are stratified out of the central estimate rather than allowed to set it: Iranian bread on a dry-weight basis reaches a total-chromium mean of 1,000 µg/kg with a standard deviation of 1,420 at 63 percent detection, non-detects assigned zero (Asadi Touranlou et al. 2025, n=248, dry-weight ICP-OES), and wheat grain from the karst and lead-and-phosphate-mining region of Guizhou, China reaches a mean of 3,250 µg/kg with a median of 1,488 and a maximum of 8,546 µg/kg, with 58 percent of samples above the FAO limit (Li et al. 2022, n=149, an industrial-mining region the authors attribute to industrial activity by principal-component analysis). Confidence is held at low because every contributing value is total chromium only with no Cr-VI speciation, the corpus spans a fresh-to-dry basis gap, and the industrial-region and dry-weight strata reach two orders of magnitude above the clean-market central. The prior chromium cell carried a high-confidence headline anchored on an infant-formula survey (Rahati et al. 2026, chromium mean 0.5 mg/kg in infant formula); that commodity-mismatched source has been removed from the wheat chromium synthesis.

Why this commodity accumulates cadmium

Wheat takes up cadmium from soil through its root system, with uptake efficiency influenced by soil cadmium concentration, zinc status, soil pH, and cultivar. Durum wheat has been documented as a more efficient cadmium accumulator than common bread wheats, producing elevated cadmium in pasta-grade wheat products. Within the wheat kernel, cadmium partitions preferentially to the bran and germ rather than the endosperm, so refined white flour carries the lowest cadmium among common wheat derivatives and whole-wheat products carry the highest.

Ranges by source, region, and variety

Pending ingest of commodity-level occurrence data. EFSA 2009 Table 1 reports a mean cadmium concentration for wheat grain and flour of 0.030 mg/kg and for wheat bran and germ of 0.065 mg/kg, reflecting the approximately two-fold bran-over-endosperm concentration factor. Durum wheat, rice bran, and whole-wheat products in cadmium-elevated growing regions carry values above the category mean.

Processing effects

Pending. Milling that removes bran and germ lowers the cadmium content of the resulting flour relative to whole grain; fermentation and baking do not remove cadmium. Wheat-protein isolation (vital wheat gluten) concentrates cadmium from the source grain proportionally with protein enrichment.

Ingredient-derivative risk

Derivative wheat products vary substantially in cadmium content by the fraction of the kernel they represent. Refined white flour, semolina, and pasta made from refined wheat are at or near the endosperm-level mean; whole wheat flour, bran-enriched cereals, wheat bran supplements, and wheat germ products are above the whole-grain mean by the bran-concentration factor. Wheat protein products (vital wheat gluten, seitan) concentrate cadmium from the source grain; per-product characterization is necessary.

Mitigation options

Pending. Cultivar selection (non-accumulator lines), zinc amendment of soils (zinc-cadmium antagonism reduces plant cadmium uptake), soil pH management, and milling practices that remove bran and germ are the primary mitigation levers.

Other metals of concern

Some metals not listed in this section because no ingested source yet covers their commodity-level concern; those will populate when the corresponding source pages are ingested.

• Pb: the FDA Closer to Zero 20 ppb Pb action level for dry infant cereals applies to wheat-based infant cereal (FDA CTZ Pb 2025; see fda-ctz-Pb-cereal-20ppb).

Regulatory limits that apply

• codex-cadmium-mls — Codex matrix-level Cd ML for cereal grains (pending ingest of CXS 193-1995). The CCCF17 2024 discussion on quinoa (held separate from cereals at 0.15 mg/kg) recorded that one Member delegation cited cereals as a “serious contributor to exposure to cadmium” in their region, consistent with the wiki’s cross-source synthesis.
• eu-2023-915-cadmium — EU Cd maximum levels for cereals: 0.10 mg/kg (100 ug/kg) for cereals except listed rows; 0.050 mg/kg (50 ug/kg) for barley and rye; 0.15 mg/kg (150 ug/kg) for rice, quinoa, wheat bran, and wheat gluten; 0.18 mg/kg (180 ug/kg) for durum wheat; 0.20 mg/kg (200 ug/kg) for wheat germ.
• fda-ctz-Pb-cereal-20ppb — FDA CTZ 20 ppb lead action level for dry infant cereals is the adjacent Pb rule; any future Cd analogue under the CTZ program would apply similarly to wheat-based infant cereal.

Nickel in wheat

Flyvholm et al. 1984 reports wheat flour mean Ni at 0.13 µg/g (range 0.03 to 0.3 µg/g, n=32 samples) and whole wheat at 0.33 µg/g (range 0.1 to 0.8 µg/g, n=85). The roughly 2.5x concentration gap between whole-grain wheat and refined flour reflects the bran fraction’s accumulation of Ni, parallel to the bran-effect on Cd and Mn. In the Danish average diet model, wheat flour contributes 14.7 µg Ni/day (10 percent of total dietary Ni) at a load factor F = 1.9; wheat is therefore a meaningful per-day Ni source by volume, though not a high per-gram contributor on the order of cocoa, soy, or oats. Whole wheat at 0.33 µg/g is roughly 5x higher than white bread (0.27 µg/g, n=65 samples), supporting the bran-versus-endosperm pattern.

Sources

Auto-generated from source-page frontmatter. The “Used on this page for” column is populated by the orchestrator’s POPULATE-SOURCE-LEGEND action; pending entries appear as *[awaiting synthesis]*.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.