Chromium is an essential trace mineral and deficiency causes hyperglycaemia and impaired lipid metabolism, which are reversed upon administration of chromium. Chromium results in blood glucose and lipid problems because it is an essential part of the chromodumlin molecule that is required by the insulin receptor to transport glucose into cells. Some researchers have suggested that chromium deficiency may be involved in the progression of type 2 diabetes. Generally diabetic symptoms are displayed in animals given sub optimal chromium levels and they take several months to manifest. High intakes of sugar, stress and physical activity are known to cause increased chromium excretion because the mobilisation of chromium is needed to deal with blood sugar rises as might occur in these situations. Mobilisation of chromium to lower blood glucose levels results in loss of that chromium in the urine and with must then be replaced in the diet.
For example, researchers1, have investigated various types of carbohydrate drinks on the urinary chromium excretion. Subject were fed either 1.0g glucose, 0.9g uncooked cornstarch, 1.0g glucose followed 20 min later by 1.75g fructose, 0.9g uncooked cornstarch followed 20 min later by 1.75g fructose or water followed 20 min later by 1.75g fructose, per kg body weight. Each of the 20 subjects consumed each drink with a 2 week washout period between tests. The results showed that glucose plus fructose caused the largest rise in insulin levels, followed by glucose alone, starch plus fructose and then starch alone. Fructose plus water had a minimal effect on blood insulin levels. Generally, the urinary losses of chromium followed a similar pattern to those reported for the effects on insulin with the higher the insulin response to the sugar, the higher the loss of chromium in the urine.
These results suggests that fructose given has a minimal effect on the insulin levels in blood when given in isolation, but does cause exacerbation of blood insulin levels when given 20 min after glucose or starch. However, the increase in insulin levels is independent of the blood glucose levels as these were not affected by the fructose induced insulin spike. Closer analysis of the subjects with an insulin response >718pmol/L after consumption of glucose plus fructose showed that these subjects had a significantly higher insulin with glucose plus fructose compared to glucose alone, but that this rise in insulin was not accompanied by an increase in urinary chromium excretion. This suggests that these subjects are unable to mobilise chromium in response to the higher insulin response and may therefore be deficient in chromium. These results also suggest that urinary chromium excretion is related to the insulinogenic properties of carbohydrates.
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