Glucose tolerance factor

Chromium deficiency is described as the consequence of an insufficient dietary intake of the mineral chromium. Chromium was first proposed as an essential element for normal glucose metabolism in 1959, and was widely accepted as being such by the 1990s. Cases of deficiency were described in people who received all of their nutrition intravenously for long periods of time. The essentiality of chromium has been challenged. Whereas the authorities in the European Union do not recognize chromium as an essential nutrient, those in the United States do, and identify an adequate intake for adults as between 25 and 45 μg/day, depending on age and sex. Dietary supplements containing chromium are widely available in the United States, with claims for benefits for fasting plasma glucose, hemoglobin A1C and weight loss. Reviews report the changes as modest, and without scientific consensus that the changes have a clinically relevant impact. The symptoms of chromium deficiency caused by long-term total parenteral nutrition are severely impaired glucose tolerance, weight loss, peripheral neuropathy and confusion. According to the Dietary Reference Intake review, neither plasma nor urine concentrations can serve as useful clinical indicators of chromium status. Before chromium became a standard ingredient in total parenteral nutrition (TPN), people getting TPN as their sole source of nutrition developed symptoms that were reversed within two week after chromium was added. The U.S. Institute of Medicine (IOM) updated Estimated Average Requirements (EARs) and Recommended Dietary Allowances (RDAs) for chromium in 2001. For chromium there was not sufficient information to set EARs and RDAs, so needs are described as estimates for Adequate Intakes (AIs). The current AIs for chromium for women ages 14 and up is 25 μg/day up to age 50 and 20 μg/day for older. AI for pregnancy is 30 μg/day. AI for lactation is 45 μg/day. For men ages 14 and up 35 μg/day up to age 50 and 30 μg/day for older. For infants to children ages 1–13 years the AI increases with age from 0.2 to 25 μg/day. As for safety, the IOM sets Tolerable upper intake levels (ULs) for vitamins and minerals when evidence is sufficient. In the case of chromium there is not yet enough information and hence no UL. Collectively the EARs, RDAs, AIs and ULs are referred to as Dietary Reference Intakes (DRIs). Japan designate chromium as an essential nutrient, identifying 10 μg/day as an Adequate Intake for adults. The European Food Safety Authority (EFSA) refers to the collective set of information as Dietary Reference Values, with Population Reference Intake (PRI) instead of RDA, and Average Requirement instead of EAR. AI and UL defined the same as in United States. The EFSA does not consider chromium to be an essential nutrient, and so has not set PRIs, AIs or ULs. Chromium is the only mineral for which the United States and the European Union disagree on essentiality. For U.S. food and dietary supplement labeling purposes the amount in a serving is expressed as a percent of Daily Value (%DV). For chromium labeling purposes 100% of the Daily Value was 120 μg, but as of May 27, 2016 it was revised to 35 μg to bring it into agreement with the RDA. A table of the old and new adult Daily Values is provided at Reference Daily Intake. The original deadline to be in compliance was July 28, 2018, but on September 29, 2017 the FDA released a proposed rule that extended the deadline to January 1, 2020 for large companies and January 1, 2021 for small companies.