The association between chromium deficient diets and hyperglycaemia in rats and mice has been well reported, and the role of chromium in animal nutrition has been extensively researched. Less is known about the role of chromium in humans, partly because of the ethical problems of feeding human subjects tightly controlled laboratory food deficient in essential minerals. However, research to date suggests that chromium plays a similar role in humans as it does in rats and mice and that chromium deficiency is at least a partial cause of some blood sugar disorders, and possibly of weight gain and abdominal adiposity. For example, both hair and liver chromium are known to be lower in diabetic subjects compared to healthy individuals, and those subjects dependent on insulin have significantly higher urinary chromium excretion rates when compared to healthy controls.
Researchers1 have investigated the relationship between chromium and insulin in healthy subjects and found that the results generally support the findings from animal studies. Twelve healthy female subjects and 8 healthy male subjects were divided into two groups based on their insulin response to an oral glucose tolerance test glucose (OGTT). Those subjects with an insulin response to a 3 hour OGTT of over 500 µU/mL were placed in a high insulin secretor group and those below the 500 µU/mL level in a low insulin secretor group. At baseline, serum chromium levels were 1.46 ng/mL with a 13% variance across subjects. In addition, the researchers reported that the fasting chromium level in the subjects had a positive correlation with fasting insulin level, with triceps skin fold thickness and with the percentage of ideal body weight.
Blood samples taken after an overnight fast and then again at 0.5, 1, 1.5, 2 and 3 hours following a 100g glucose load showed that the total insulin responses was 354 and 740 µU/mL in the high and low secretor groups, respectively. The chromium response was significantly higher in the low insulin secretors than the high insulin secretors (31.0% versus 18.0%), and the ratio of total insulin to total glucose was significantly lower in the low insulin secretors compared to the high insulin secretors (0.59 versus 1.29). There was also a positive association found between the fasting insulin levels of the subjects and the tricep skin fold measurement and the percentage of ideal weight. These results support the evidence from animal studies that chromium in humans is involved in the regulation of insulin and body weight.
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