Chromium is a popular dietary supplement for controlling blood sugar and promoting weight loss, but some of what we thought we knew about chromium has been disputed in scientific studies. Let’s take a closer look at the evidence so you can decide whether you think this supplement is worth taking.
Chromium is a metal that is naturally found in many foods – in fact, chromium could be considered a heavy metal based on its molecular weight. While heavy metals are generally associated with toxicity, chromium is not toxic in its naturally occurring form known as trivalent chromium. A more oxidised form of chromium – hexavalent chromium – is primarily an industrial product and is toxic. From this point onwards, all mentions of chromium refer only to trivalent chromium.
Chromium’s main effect within the body is to enhance the action of the blood sugar-lowering hormone insulin. Insulin works by binding to receptors on the surface of cells, which causes them to absorb more glucose (sugar) from the blood. Chromium combines with other molecules within the body to form a complex called chromodulin, which seems to work by enhancing the sensitivity of these insulin receptors. Chromium also suppresses appetite, possibly by binding to different receptors located in the brain.
Chromium may also activate a molecule called AMPK under certain circumstances. AMPK is a ‘master regulator’ of energy metabolism that may play an important role in the ageing process. Our article on berberine contains a fuller explanation of AMPK and why activating it may be a good thing.
Some of the first evidence that chromium could be important for human health came from case studies of patients who were chromium deficient. These patients developed symptoms of diabetes mellitus (such as not responding properly to insulin) that went away when chromium was administered. This made people think that chromium was an essential mineral (meaning we need it in our diet in order to maintain good health). Unfortunately, there were some problems with these studies, and it remains uncertain to this day whether chromium deficiency actually happens in the general population, or whether it is even harmful when it does. This is because there is no way to accurately measure chromium levels in the body. Moreover, a carefully controlled study in rats found that 6 months on a very low chromium diet did not negatively impact their ability to control blood sugar, nor did it affect their body weight.
So, the jury’s still out on whether chromium deficiency is something that humans should be worried about. However, even if chromium intake is not necessary, chromium supplementation may still be beneficial. The best evidence comes from people with type II diabetes. A meta-analysis of randomised trials totalling over 500 participants found that chromium supplementation was associated with a significant reduction in HbA1c, which is a measure of average blood sugar levels over the preceding few months. However, there’s not yet enough evidence to say if this happens in people without type II diabetes, or whether it would significantly benefit their health.
Beyond the effects on blood sugar, there’s some evidence that chromium supplementation aids weight loss in people who are overweight or obese, such as this study in children. However, the effects are small and several studies found no benefit. Once again, there’s currently no evidence that chromium helps maintain a stable weight in people of normal weight.
Finally, a meta-analysis of clinical trials totalling around 300 participants found that chromium slightly reduced markers of inflammation, which could in theory protect against a wide range of diseases.
Clinical trials of chromium supplementation have yet to report any negative side effects. These trials generally use doses of 1000 micrograms per day at most (for reference, average daily chromium intake in food could be between 30 and 60 micrograms). However, it’s important to be aware that the safety profile of chromium is not as well established as some other supplements, and that there is no scientifically validated recommendation for how much chromium someone should be consuming, nor is there a known safe upper limit. There have been some isolated cases of severe effects seemingly related to chromium supplementation, though most of these were in people taking at least 600 micrograms per day, and sometimes over 1000 micrograms.
Chromium seems to benefit blood sugar control in people with type II diabetes and may aid weight loss in overweight and obese people. However, its effects on healthy people aren’t well studied. Chromium supplements may help to prevent chromium deficiency, but it’s unclear whether this is really a risk in the general population. Chromium appears to be safe, but further investigation is needed as there may be some risks as dosage increases.
It is always best to consult with a doctor before taking any new drug, supplement, or making significant changes to your diet.
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Examine.com: Chromium https://examine.com/supplements/chromium/
Chromium deficiency, glucose intolerance, and neuropathy reversed by chromium supplementation, in a patient receiving long-term total parenteral nutrition https://doi.org/10.1093/ajcn/30.4.531
Chromium is not an essential trace element for mammals: effects of a "low-chromium" diet https://doi.org/10.1007/s00775-010-0734-y
Effect of Chromium Supplementation on Blood Glucose and Lipid Levels in Patients with Type 2 Diabetes Mellitus: a Systematic Review and Meta-analysis https://doi.org/10.1007/s12011-021-02693-3
Effects of short-term chromium supplementation on insulin sensitivity and body composition in overweight children: randomized, double-blind, placebo-controlled study https://doi.org/10.1016/j.jnutbio.2010.10.001