Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) was asked to review the evidence with regard to the setting of Dietary Reference Values (DRVs) for the European population, including chromium.
In 1993, the Scientific Committee for Food was unable to define a specific physiological requirement of chromium and did not propose DRVs for chromium, but other authorities have subsequently proposed DRVs for chromium.
Trivalent chromium (Cr(III)) has been reported as an essential trace element in that it has been postulated to be necessary for the efficacy of insulin in regulating the metabolism of carbohydrates, lipids and proteins. However, at present, the mechanism(s) for these roles and the essential function of chromium in metabolism have not been substantiated. The postulation of chromium’s essentiality for humans was almost entirely based on case reports of patients on long-term total parenteral nutrition (TPN) who developed metabolic and neurological defects, which were reported to respond to supplementation with Cr(III). The Panel noted that the chromium concentrations in the TPN solutions that induced the presumed deficiency symptoms were not reported in all the patients studied. In the three studies in which the concentration of chromium in the TPN solution was reported, the daily chromium supply was between 5 and 10 µg; at an absorption efficiency of 5 % this amount of infused chromium is equivalent to an oral intake of 100–200 µg/day. The Panel notes that this intake is well above the estimated mean daily intakes in the 17 European countries for which data were available to perform an assessment of chronic dietary chromium intake. On the basis of these case reports, the Panel concludes that it is unclear whether deficiency of chromium has occurred in these patients and whether chromium deficiency occurs in healthy populations.
The Panel considered the criteria for the essentiality of a trace element and noted that attempts to create chromium deficiency in animal models have not produced consistent results, that there is no evidence of essentiality of Cr(III) as a trace element in animal nutrition and that Cr(III) requirements could not be established for animal feed. The Panel considered that there is a possibility that Cr(III) is an essential trace element for humans, but that there is, as yet, no convincing evidence of this. The evidence from reported improvements associated with chromium supplementation in patients on TPN is arguably the most convincing, but overall these data do not provide sufficient information on the reversibility of the possible deficiencies and on the nature of any dose–response curve in order to identify a dietary requirement for humans. The existence and functional characterisation of a chromium–oligopeptide complex (chromodulin) is still unclear.
The Panel concludes that no Average Requirement and no Population Reference Intake for chromium for the performance of physiological functions can be defined.
Nevertheless, as for fluoride, DRVs might be derived if a consistent dose–response relationship could be established between dietary chromium intake and a beneficial health outcome. A comprehensive search of the literature published between January 1990 and October 2011 was performed to identify relevant health outcomes upon which DRVs for chromium may potentially be based. Several studies that assessed the effect of chromium supplementation on glucose and/or lipid metabolism were retrieved in the literature search. In most studies, chromium intake from the diet was not assessed, and information on total chromium intake is therefore not available. In one cross-over study for which total chromium intake was available, there was no significant difference in the parameters of glucose metabolism between the placebo and chromium-supplemented periods in normoglycaemic subjects. The Panel considered that there is no evidence of beneficial effects associated with chromium intake in healthy subjects. The Panel concludes that the setting of an Adequate Intake for chromium is also not appropriate.