Following a request from the European Commission to the European Food Safety Authority (EFSA), the Scientific Panel on Food Additives and Nutrient Sources added to Food (ANS) was asked to provide a scientific opinion on the safety of chromium(III) nitrate as a source of chromium added for nutritional purposes to food supplement and on the bioavailability of chromium from this source.

The present opinion deals only with the safety of a particular source of chromium, chromium(III) nitrate, intended to be used in food supplements and with the bioavailability of chromium from this source. The safety of chromium itself, in terms of the amounts that may be consumed, is outside the remit of this Panel.

In the adult population (over 18 years old), assuming mean and 97.5th percentile European dietary chromium(III) intakes in the ranges of 60–160 µg/day and 126-170 µg/day, respectively, consumption of food supplements containing 500 µg chromium(III)/day (the highest use level proposed by the petitioner) would result in a total anticipated daily chromium intake, from food and food supplements, between 560 and 660 µg chromium(III)/day at the average level of dietary exposure and between 626 and 670 µg/day at the high level of dietary exposure, if no other food supplements containing chromium(III) were taken.

In children aged 3 to 17 years old, assuming mean and 97.5th percentile dietary chromium(III) intakes in the ranges of 63–69 µg/day and 107-119 µg/day, respectively, consumption of food supplements containing 500 µg chromium(III)/day (the highest use level proposed by the petitioner) would result in a total anticipated daily chromium intake, from food and food supplements, between 563 and 569 µg chromium(III)/day at the average level of dietary exposure and between 607 and 619 µg/day at the high level of dietary exposure, if no other food supplements containing chromium(III) were taken.

No bioavailability data specific for chromium(III) nitrate were presented but, the petitioner states that being highly soluble, chromium(III) nitrate fully dissociates into its two components (nitrate and chromium(III)) in the stomach and therefore it should be absorbed in the same manner as chromium(III) chloride. In the absence of specific supporting data, this statement cannot be evaluated but the Panel considers that the bioavailability of chromium(III) from chromium(III) nitrate could be expected to be similar to that for other inorganic soluble chromium salts. In any case, this absorption is low (0.5-2%).

If, as stated by the petitioner, the compound readily dissociates in the stomach, the Panel considers that the safety of the compound must be assessed regarding its two components: nitrate and chromium(III).

Nitrates have been assessed by the Scientific Committee on Food (SCF), EFSA and the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the estimated dietary exposure to nitrate is about 157 mg/day. Given the proposed uses for chromium(III) nitrate as a food supplement, a daily intake of 0.5 mg of chromium(III) will be associated with a daily intake of approximately 1.8 mg of nitrate. The Acceptable Daily Intake (ADI) for nitrate is 3.7 mg/kg bw/day, equivalent to 222 mg/day for a 60 kg adult. On the basis of the information available in the dossier, given the proposed use levels presented by the petitioner and the resulting exposure to nitrate, the Panel concludes that the amount of nitrate that would be consumed as a result of the proposed uses of chromium(III) nitrate as a source of chromium would not be of safety concern.

The toxicity of chromium compounds has been evaluated by various authorities including the SCF, the UK Expert group on Vitamin and Minerals (EVM), the US Food and Nutrition Board (FNB) and the World Health Organization (WHO).

The SCF has issued an opinion on the Tolerable Upper Intake Levels (ULs) of trivalent chromium (chromium(III)) and concluded that limited data from studies on subchronic, chronic and reproductive toxicity on soluble trivalent chromium salts and the available human data do not give clear information on the dose-response relationships and therefore a UL could not be derived.

The US FNB concluded that data from animal and human studies are insufficient to establish a UL for soluble trivalent chromium salts.
The EVM also concluded that overall there are insufficient data from human and animal studies to derive a safe upper level for chromium. However, in the EVM opinion it was indicated that a total daily intake of about 0.15 mg chromium(III)/kg bw/day (or 10 mg/person) was expected to be without adverse health effects.

The WHO considered that supplementation of chromium in adults should not exceed 250 µg/day.

Information on the toxicity of chromium(III) is limited but given the available data the Panel concludes that the use of chromium(III) nitrate as a source of chromium(III) in food supplements would not be of safety concern provided that the level for supplementation of 250 µg chromium/day recommended by the WHO is not exceeded.

In addition, the Panel notes that recent reviews and evaluations of chromium(III) point at conflicting outcomes of genotoxicity assays and report diverging views and conclusions on the consequences of this genotoxicity issue for the ultimate safety assessment of chromium(III). The Panel notes that additional relevant in vivo studies have shown that exposure to chromium(III) chloride and chromium(III) nitrate induced DNA deletions in mice and yeast respectively and that it was recently reported that occupational exposure to chromium(III) can lead to DNA damage to human peripheral lymphocyte as evidenced by the Comet assay. The Panel is aware that given this situation the safety of chromium(III) might need to be re-evaluated in light of these recent reviews and evaluations.

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