Syndrome X or metabolic disorder is a condition characterised by insulin resistance and may represent the early signs of type 2 diabetes. The symptoms of this syndrome are glucose intolerance, hyperinsulinaemia, increased LDL-cholesterol, increased triglycerides, elevated total cholesterol and decreased HDL-cholesterol, increased fat mass and decreased lean body mass. The outward manifestation of metabolic syndrome are a slow but steady gain in mainly abdominal visceral fat and a slow deterioration in health and energy levels. It just so happens that these symptoms are also similar to the symptoms caused by a deficiency of the essential trace mineral chromium. This might lead one to question whether the rise in prevalence metabolic syndrome seen in the general population is in fact a widespread chromium deficiency. So what is chromium and why is it important to health? And does chromium lower body fat?
Chromium is an essential trace mineral required for human health because it is an essential component of the insulin receptor. Cells have receptors for insulin, with binding being necessary for glucose entry to the cell. When insulin binds to the receptor it activates glucose uptake, thus lowering blood glucose levels. However, this process also requires chromium. In response to rising blood sugar levels, chromium leaves the blood and enters the insulin sensitive cells where it forms a complex that binds to the insulin receptor and allows it to be activated by insulin. As blood sugar and insulin levels drop, the chromium unbinds from the insulin receptor and is lost from the cell and excreted in the urine. If this chromium is not replaced with new chromium in the diet, the insulin receptors gradually become less able to bind to insulin, which results in raised blood sugar levels. This sugar has to go somewhere and so it is pushed into fat cells where it is converted to fat.
Assuming that the chromium that is used up becomes replaced by new dietary chromium, everything will continue to work as it should. However, if the rate of excretion exceeds the rate of intake, a chromium deficiency can develop. This is problematic because evidence suggests that mineral intakes are not adequate due to mineral depleted soils. When humans eat the mineral deficient plants grown in mineral deficient soils, they also become mineral deficient. A study published in the British Journal of Nutrition in 2007 measured chromium levels in free-living French people and found that although the people were eating balanced healthy diets, their chromium contents did not reach the recommended levels1. Another paper published in the American Journal of Clinical Nutrition published in 1985 demonstrated that self selected diets of healthy Americans provide levels of chromium well below the recommended levels2.
As well as inadequate intakes, it is also known that stress can cause a deficiency of chromium. Exercise, physical trauma and infection all cause the body to compromise chromium levels via increased excretion rates. Of particular interest however is the fact that high sugar intakes are also able to deplete the body of chromium. This makes perfect sense because it is known that after chromium has bound to the insulin receptor it is expelled from the cell into the blood. The body cannot reabsorb chromium from the kidneys and so once it is mobilised from cells it is lost in the urine. It would appear therefore that western diets are not only inadequate in chromium content, but also the high sugar content consumed in those diets also creates a chromium deficiency in the tissues. This low chromium high sugar intake may be one of the leading causes of the weight problems in developed nations today. In particular chromium deficiency may increase the risk of metabolic syndrome.
It seems self evident to therefore that supplemental chromium is important to anyone wanting to maintain optimal health and avoid weight gain. Food is just not able to provide even the low levels of chromium recommended. Trivalent chromium, the sort found in food and supplements is one of the least toxic of the trace minerals and is incredibly safe. Current safety limits for chromium are set at thousands of times the current recommended levels. Many studies have shown that chromium is able to increase insulin sensitivity when supplements are given, and improvements in lean body mass have been seen in studies with humans. For example, a meta-analysis of several human studies3 reported a reduction in body weight of between 1.1 kg during chromium supplementation. It would appear therefore that long term, 200 to 600 micrograms of chromium could be a very useful tool in a weight loss programme in order to guard against a chromium deficiency.
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