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Safety Evaluation of Certain Food Additives and Contaminants WHO FOOD Safety evaluation of ADDITIVES SERIES: 58 certain food additives and contaminants Prepared by the Sixty-seventh meeting of the Joint FAO/WHO Expert Committee on Food Additives (JECFA) ALUMINIUM (addendum) (pages 119-207) World Health Organization, Geneva, 2007 IPCS — International Programme on Chemical Safety ALUMINIUM FROM ALL SOURCES, INCLUDING FOOD ADDITIVES (addendum) First draft prepared by D.J. Benford,1 N. Thatcher,1 D. Mason,1 D. Street,2 C. Leclercq,3 M. DiNovi,2 J. Bend4 & B. Whitehouse5 1 Food Standards Agency, London, England; 2 Center for Food Safety and Applied Nutrition, United States Food and Drug Administration, College Park, MD, USA; 3 Food Safety Exposure Analysis, Istituto Nazionale di Ricerca per gli Alimenti e la Nutrizione (INRAN), Rome, Italy; 4 Department of Pathology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario, Canada; and 5Bowdon, Cheshire, England Explanation ................................................................................ 120 Introduction ......................................................................... 120 General considerations on exposure ............................ 121 Biological data ........................................................................... 121 Biochemical aspects ........................................................... 121 Absorption, distribution and excretion ........................... 121 Effects on enzymes and other parameters ................... 130 Toxicological studies ........................................................... 132 Acute toxicity ................................................................. 132 Short-term studies of toxicity ........................................ 132 Long-term studies of toxicity and carcinogenicity ......... 135 Genotoxicity .................................................................. 135 Reproductive toxicity ..................................................... 136 Special studies .............................................................. 142 Observations in humans ............................................................ 149 Biomarkers of exposure ...................................................... 149 Biomarkers of effects .................................................... 149 Clinical observations ..................................................... 149 Epidemiological studies ................................................ 152 Analytical methods .................................................................... 174 Food additives ..................................................................... 174 Food samples ..................................................................... 174 Sampling protocols .................................................................... 175 Exposure to aluminium in the diet and other sources ............... 175 Dietary exposure (including drinking-water) ........................ 175 Drinking-water ............................................................... 176 Aluminium from natural dietary sources ....................... 177 - 119 - 120 ALUMINIUM FROM ALL SOURCES, INCLUDING FOOD ADDITIVES Aluminium migrating from food-contact material (food containers, cookware, utensils and packaging) ............ 177 Aluminium present in food additives ............................. 178 Assessment of total dietary exposure ........................... 182 Other sources of exposure .................................................. 186 Inhalation ...................................................................... 186 Dermal exposure to consumer products containing aluminium ..................................................................... 186 Consumption of medicines containing aluminium ......... 186 Effects of processing ................................................................. 187 Dose–response analysis and estimation of risk of carcinogenicity/toxicity ............................................................... 187 Contribution of data to assessment of risk .......................... 187 Pivotal data from biochemical and toxicological studies .......................................................................... 187 Pivotal data from human clinical/epidemiological studies .......................................................................... 190 Comments ................................................................................. 190 Evaluation .................................................................................. 196 References ................................................................................ 198 1. EXPLANATION 1.1 Introduction Various aluminium compounds were evaluated by the Committee at its thirteenth, twenty-first, twenty-sixth, twenty-ninth, thirtieth and thirty-third meetings (Annex 1, references 20, 44, 59, 70, 73 and 83). At its thirteenth meeting, an acceptable daily intake (ADI) ‘not specified’ was established for sodium alumino- silicate and aluminium calcium silicate (Annex 1, reference 20). At its thirtieth meeting, the Committee noted concerns about a lack of precise information on the aluminium content of the diet and a need for additional safety data. The Committee set a temporary ADI of 0–0.6 mg/kg bw expressed as aluminium for all aluminium salts added to food, and recommended that aluminium in all its forms should be reviewed at a future meeting. In the evaluation made by the Committee at its thirty-third meeting (Annex 1, references 83, 84), emphasis was placed on estimates of consumer exposure, absorption and distribution of dietary aluminium and possible neurotoxicity, partic- ularly the relationship between exposure to aluminium and Alzheimer disease. The Committee set a provisional tolerable weekly intake (PTWI) of 0–7.0 mg/kg bw for aluminium, including food additive uses. This was based upon a study in which no treatment-related effects were seen in beagle dogs given diets containing sodium aluminium phosphate (SALP) acidic at a concentration of 3% for 189 days, equivalent to approximately 110 mg/kg bw aluminium. A consolidated monograph was produced (Annex 1, reference 84). Aluminium was re-evaluated by the Committee at its present meeting, as requested by the Codex Commission on Food Additives and Contaminants (CCFAC) at its Thirty-seventh Session (Codex Alimentarius Commission, 2005). ALUMINIUM FROM ALL SOURCES, INCLUDING FOOD ADDITIVES 121 The Committee was asked to consider all data relevant to the evaluation of the toxicity and intake (including bioavailability) of aluminium used in food additives and from other sources, including SALP. CCFAC asked that the exposure assessment cover all compounds included in the Codex General Standard for Food Additives (GSFA). Two documents were particularly important in the evaluation made by the Committee at its present meeting: the International Programme on Chemical Safety (IPCS) Environmental Health Criteria document on aluminium (WHO, 1997) and a report by the United Kingdom (UK) Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) on a water pollution incident that occurred in Cornwall, England in 1988 (COT, 2005). The Committee used those assessments as the starting point for its evaluation and also evaluated other data in the scientific literature relating to aluminium compounds. No original toxicological data on aluminium-containing food additives were submitted. 1.1.1 General considerations on exposure Aluminium is the third most abundant element and a major constituent of the earth’s crust, where it is present as Al3+ in combination with oxygen, fluorine, silicon and other constituents, and not in the metallic elemental state. It is released to the environment both by natural processes and from anthropogenic sources. It is naturally present in varying amounts in most foodstuffs, and concentrations in food crops are influenced by geographical region. Use of aluminium and aluminium compounds in processing, packaging and storage of food products, and as flocculants in the treatment of drinking-water may contribute to its presence in drinking-water and foods. A number of aluminium salts are used as food additives (see section 6.1.4). In general, the foods that contain the highest concentration of aluminium are those that contain aluminium additives (WHO, 1997). 2. BIOLOGICAL DATA 2.1 Biochemical aspects 2.1.1 Absorption, distribution and excretion (a) Absorption The mechanism of gastrointestinal absorption of aluminium is complex and has not yet been fully elucidated (WHO, 1997). The extent to which aluminium is absorbed depends upon the amount of the chemical species present in the gut lumen, in the blood and in the interstitial fluid. Aluminium species may be modified in the gut before absorption. Absorption will also be influenced by complexing ligands (e.g. citrate, lactate) and competing ions (e.g. iron, silicon). Some authors have suggested that acid digestion in the stomach would solubilize the majority of ingested aluminium to the monomolecular species. This would then be converted to the aluminium hydroxide as pH is neutralized in the duodenum. The solubility of Al3+ is lowest at neutral pH. Most of the substance is expected to precipitate in the 122 ALUMINIUM FROM ALL SOURCES, INCLUDING FOOD ADDITIVES intestine, making it unavailable for uptake, with subsequent faecal excretion. Aluminium complexes, particularly in the presence of carboxylic acids such as citrate, are thought to improve solubility in the
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