Fechner et al. 2019 — Cocoa-origin effects on Al and Cd dietary exposure (German market)
This German Federal Institute for Risk Assessment (BfR) study integrated German Food Monitoring (GFM) occurrence data for Al and Cd in cocoa powder (2005–2015) with German National Nutrition Survey II (NVS II) consumption data (n = 15,371 participants) to assess whether cocoa geographical origin materially affects dietary exposure estimates. The most conservative standard scenario (P95 concentrations × P95 consumption) yielded maximum intake estimates of 0.152 mg/week/kg BW for Al and 0.363 µg/week/kg BW for Cd from cocoa powder — representing 15% of the Al TWI (1 mg/week/kg BW) and 14% of the Cd TWI (2.5 µg/week/kg BW) respectively. Origin-grouped scenarios (grouping lower-concentration vs. higher-concentration samples) showed modest differentiation but did not substantially exceed the conservative standard scenario, suggesting that origin-specific information adds refinement but does not change the headline exposure picture for the German population.
Key numbers
- Cocoa consumption (NVS II consumers only, 12,482 cocoa-powder consumers; 3,802 cocoa-mass consumers; 12,482 cocoa-sum): P50 0.014 g/d/kg BW, P95 0.098 g/d/kg BW (cocoa sum)
- Most conservative standard scenario (Scenario 4, P95 concentration × P95 consumption):
- Aluminium: 0.152 mg/week/kg BW (15% of TWI 1 mg/week/kg BW)
- Cadmium: 0.363 µg/week/kg BW (14% of TWI 2.5 µg/week/kg BW)
- Most conservative origin-related scenario (Scenario 8, mean concentrations from origin B × P95 consumption):
- Aluminium: 0.136 mg/week/kg BW (Grouping 1), 0.142 mg/week/kg BW (Grouping 2)
- Cadmium: 0.203 µg/week/kg BW (Grouping 1), 0.230 µg/week/kg BW (Grouping 2)
- Scenario 8 for Cd was 8–9% of the Cd TWI, substantially below Scenario 4 (14%), indicating P95 concentration methodology is more conservative than origin-B grouping
- GFM data period: 2005–2015; cocoa powder analysed 2008 and 2012
- German market: cocoa beans for Germany mainly sourced from Côte d’Ivoire (Netherlands was main distributor); cocoa powder labels rarely stated country of origin
Methods (brief)
Occurrence data: GFM monitoring (2005–2015) for Al and Cd in cocoa powder. Consumption data: German NVS II dietary history interview (November 2005–2006, 15,371 participants aged 14–80 years, 4 seasonal waves). Exposure scenarios: 8 scenarios combining mean/P95 concentrations (all samples, origin A, origin B) × mean/P95 consumption. Origin grouping: two methods — Grouping 1 (equal thirds by ranked concentration) and Grouping 2 (P25 as upper limit of segment 1, P75 as lower limit of segment 3). SPSS version 21; Kolmogorov-Smirnov normality test; Kruskal-Wallis with Dunn-Bonferroni post-hoc. Al concentrations were normally distributed; Cd were not.
Limitations
Origin information on GFM cocoa powder samples was rare — origin grouping was a theoretical sensitivity analysis, not empirical origin-stratified data. Germany labeling rules did not require country of origin for processed cocoa products, only place of processing. The study is exposure assessment, not occurrence measurement — concentration data are from GFM, not primary sampling. Consumption data cover adults only (14–80 years); infants, toddlers, and children are not included.
Implications
- Certification: Demonstrates that even P95-concentration × P95-consumption scenarios keep Al and Cd from cocoa below 15% of respective TWIs for German adults — meaning cocoa is a moderate but not dominant contributor. Origin-related refinement is possible but modest in impact for population-level exposure.
- Courses: Excellent illustration of how origin information could theoretically refine dietary exposure assessment but in practice rarely changes headline conclusions for aggregate populations. The geographic variance sub-field in the ingredient page should note the high-vs-low concentration origin grouping approach used here.
- App: Cocoa powder Al at P95 concentration was the primary driver; Cd at P95 was substantially lower as a fraction of TWI than Al. Useful for weighting Al vs. Cd risk in cocoa-based products.
- Microbiome: Not primary topic.