Chromium is an essential trace mineral required for the correct function of the insulin receptor. In this regard chromium plays an important role in glucose metabolism. Increasingly it is being recognised that the Western diet supplies insufficient chromium for optimal health, and this is largely a result of the low amount present in processed foods in combination with increased excretion caused by the high sugar content of the diet. Theory suggests that part of the cause of the high incidence of obesity in developed nations is due to the low intakes of chromium. Chromium deficiency interferes with the action of insulin, and this in turn leads to insulin resistance, metabolic syndrome and obesity. Refining of grains is one of the largest contributors to the low amounts of chromium in the Western diet as most of the chromium content of cereal grains is discarded in the bran and germ layers during the manufacture of refined white flour. However, actual deficiencies of chromium are rare and most individuals ingest enough chromium to prevent short term disease.
For example, in one metabolic balance study1, researchers assessed the chromium balance of a group of apparently elderly subjects one of whom had impaired glucose tolerance. The mean intakes of energy for the men and women in the study were 2150 and 1650 kcals, respectively. The mean daily chromium intake was 29.8 μg for men and 20.1 μg which is below the current recommended European Union level of 40 μg per day. In addition, the researchers reported no correlation between the plasma glucose and the chromium parameters measured. This study was careful not to use materials in the preparation of sample that could contaminate the results, as this has been shown to be problematic in previous studies where chromium containing steel containers have been used. Therefore these results are likely accurate measurements of the true chromium parameters of the subjects. Overall then the subjects had lower chromium intakes than the recommended levels, but no visible signs of clinical trouble caused as a result of this.
These results are interesting because they suggest that low chromium intakes are not a cause of short-term ill health in free living subjects. However, the lack of obvious clinical symptoms does not mean that the health of the subjects was not affected by the low chromium intakes. The recommended levels for essential nutrients are designed to meet the needs of most individuals under normal circumstances, for example without undue stress or physical exertion being present. These recommended levels are based on detailed scientific findings and recommendations by experts on the known short-and long-term effects of insufficient intakes. The subjects were in chromium balance in this study suggesting that their intakes were matched to their excretion. However, this does not mean that the levels of chromium in their tissues was sufficient, just that they had adapted to the low intakes with reduced excretion rates. Such adaptation is seen in many other nutrients including selenium, and is a reasonable explanation as to how insufficient levels of nutrients can allow the maintenance of health at least in the short-term.
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