EFSA — Tolerable Weekly Intake for Cadmium, 2.5 µg/kg b.w./week

The European Food Safety Authority Panel on Contaminants in the Food Chain established a tolerable weekly intake for cadmium of 2.5 µg per kilogram body weight per week in its scientific opinion adopted 30 January 2009 (EFSA Cd 2009). The TWI is the EU health-based reference value for lifetime dietary cadmium exposure, against which member-state regulatory decisions, the Codex Alimentarius maximum levels adopted into EU law through Regulation (EC) No. 1881/2006, and subsequent food safety interventions are evaluated. It superseded the long-standing Joint FAO/WHO Expert Committee on Food Additives provisional tolerable weekly intake of 7 µg/kg b.w./week that had been in place since the 1980s, cutting the reference value by a factor of approximately 2.8 (EFSA Cd 2009).

TWI value

TWI parameters from EFSA Cd 2009:

Parameter	Value
TWI	2.5 µg Cd/kg body weight per week
Adopted	30 January 2009
Adopting body	EFSA Panel on Contaminants in the Food Chain
Basis document	Scientific Opinion, Question No EFSA-Q-2007-138, EFSA Journal 2009;980:1-139
Previous reference value superseded	JECFA/Scientific Committee for Food PTWI of 7 µg/kg b.w./week

Critical endpoint

Renal tubular dysfunction. The Panel selected urinary beta-2-microglobulin (B2M), a low molecular weight protein, as the biomarker most useful in relation to tubular effects (EFSA Cd 2009). Elevated urinary B2M reflects the earliest biological response to cadmium-induced damage to proximal tubular cells in the kidney cortex, where cadmium accumulates over a biological half-life of 10 to 30 years.

The quantitative dose-response anchor is a group-based benchmark dose lower confidence limit for a 5 percent increase in the prevalence of elevated B2M (BMDL5) of 4 µg cadmium per gram creatinine in urine, derived through meta-analysis of human studies. A chemical-specific adjustment factor of 3.9 was applied to account for inter-individual variation in urinary cadmium within the dose subgroups, producing a reference point of 1.0 µg Cd per gram creatinine (EFSA Cd 2009).

How the TWI was derived from the reference point

The reference point of 1.0 µg Cd per gram creatinine in urine is a body-burden target, not a dietary-intake value. The translation from urinary cadmium to dietary cadmium used a one-compartment toxicokinetic model fit to a large dataset of non-smoking Swedish women aged 58 to 70, including both dietary intake measurements and urinary cadmium measurements (EFSA Cd 2009). The model answers the question: what daily dietary cadmium intake, sustained over a lifetime, keeps 95 percent of the population below the 1.0 µg/g creatinine urinary reference point by age 50?

The answer produced by the model is a daily dietary intake of 0.36 µg Cd per kg body weight. Expressed as a weekly dietary intake to reflect cadmium’s cumulative nature, this is 2.52 µg/kg b.w./week, rounded to the published TWI of 2.5 µg/kg b.w./week (EFSA Cd 2009). No additional uncertainty or adjustment factor was applied because the data already derive from an early biological response endpoint and from a sensitive population (post-menopausal women with completed lifetime exposure).

Dietary exposure relative to the TWI

The Panel estimated that mean adult European dietary cadmium exposure is 2.3 µg/kg b.w./week (range across Member States 1.9 to 3.0), which places the mean exposure close to or slightly exceeding the TWI (EFSA Cd 2009). High consumers across Member States range from 2.5 to 3.9 µg/kg b.w./week, with vegetarians reaching up to 5.4 µg/kg b.w./week, regular bivalve mollusc consumers at 4.6, and regular wild mushroom consumers at 4.3 (EFSA Cd 2009). Children had mean exposure approximately 60 percent greater than adults due to greater food intake relative to body weight (EFSA Cd 2009).

The Panel’s risk characterization concluded that adverse effects on kidney function are unlikely for an individual exposed at the current average European level, but that population-level cadmium exposure should be reduced given that subgroups may exceed the TWI by about twofold and given that the TWI itself represents a body-burden target that becomes less achievable as exposure accumulates over decades (EFSA Cd 2009).

Relationship to EU maximum levels

The TWI is the health-based reference value; enforceable maximum levels for cadmium in specific food commodities are set separately through Regulation (EC) No. 1881/2006 and subsequent amendments (as of this ingest, Regulation (EU) 2023/915 is the consolidated successor regulation). The opinion notes that at the time of adoption, most foods had fewer than 5 percent of samples exceeding the applicable EU ML, with exceptions for celeriac, horse meat, fish, and bivalve molluscs other than oysters and cephalopods (EFSA Cd 2009).

The 2011 reaffirmation

The Joint FAO/WHO Expert Committee on Food Additives adopted a different reference value for cadmium in 2010, a provisional tolerable monthly intake of 25 µg/kg b.w./month (JECFA 73rd 2010), which expressed on a weekly basis (approximately 5.8 µg/kg b.w./week) is about 2.3 times the EFSA TWI. EFSA issued a statement in 2011 reaffirming the 2009 TWI and explaining the derivation differences between the two bodies (EFSA Cd 2011).

The 2011 statement primary PDF is provenance-recorded but not yet primary-source-verified; the source page is a secondary-citation provenance record (EFSA Cd 2011). The TWI numeric value is unchanged by the 2011 statement; what the 2011 statement provides is the EFSA-side articulation of why the EU and the international JECFA value differ. This divergence is a load-bearing fact for the wiki’s synthesis of cadmium reference values and is reflected in synthesis.

Comparison to other reference values

Pending ingests. The tabular comparison of EFSA TWI, JECFA PTMI, EPA IRIS RfD, and ATSDR MRLs will populate here as those documents are ingested in the current batch.

Sources

• EFSA Cd 2009 — EFSA Panel on Contaminants in the Food Chain, 2009. Scientific Opinion on Cadmium in Food (evidence tier A, public-reference-only license).

Pending: EFSA 2011 statement reaffirming the TWI after the JECFA 2010 PTMI.