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Study under review: Carcinogenic Chromium(VI) Compounds Formed by Intracellular Oxidation of Chromium(III) Dietary Supplements by Adipocytes
There is some evidence that suggests chromium supplementation can lower the fasting plasma glucose level in people with diabetes, although its impact on hemoglobin A1C, a test that reflects longer-term glucose control, is not completely clear. Nor is it clear exactly how it works to lower glucose levels. One of the main hypotheses for chromium’s mechanism involves a small protein fragment (i.e. a peptide) known as chromodulin, sometimes called low molecular-weight chromium-binding substance (LMWCr).
As shown in Figure 1, chromodulin is thought to work by binding chromium (hence its name) and amplifying the insulin receptor’s response to insulin, so that the insulin signal causes a stronger response, resulting in greater glucose uptake from the blood. That’s a great story. The only problem with it is that chromodulin may not exist.
Adapted from: Phung et al. Am J Health Syst Pharm. 2010 Apr.
Previous work from the authors of the paper under review suggests that chromodulin may be an artifact of how previous studies, which reported its discovery and isolation, were performed. The authors report that chromium seems to like to bind to all sorts of larger proteins that have some specific sequences. Then, when researchers break apart cells to study what’s binding chromium, they also break apart the proteins that were binding chromium. Thus, what comes out are low-weight bits of protein (peptides) stuck to chromium. So, according to these authors, what people have been calling “chromodulin” all this time isn’t a special peptide. It’s actually just broken-off bits from other, larger proteins that like to stick to chromium.
The good news is that, according to the authors, there’s still a possible mechanism by which chromium could lower blood glucose levels even if chromodulin doesn’t exist. The bad news, according to the authors, is that the very same mechanism may involve a potentially toxic byproduct.
The form of chromium that is normally ingested as a supplement is known as chromium (III) (CrIII). It is considered relatively safe. The Roman numeral “III” refers to chromium’s oxidation state. CrIII is the kind of chromium that you’ll find in most chromium supplements, usually bound to a molecule of picolinate. However, other more oxidized forms of chromium such as CrV and CrVI can cause DNA damage, which could lead to cancer.
Other Articles in Issue #17 (March 2016)
Kneed relief? Try collagen
Glucosamine has gotten the bulk of public attention concerning joint health, and most of the studies, but small amounts of undenatured collagen may be as or more effective for arthritis symptoms.
Fish oil and football: an unlikely pair
Head trauma from football, and its delayed (and catastrophic) health effects, are a major issue in sports today. What if something as simple as fish oil supplementation could help with this
- Interview: Marie Spano, MS, RD
Protein: sleep fuel?
Protein is typically thought of as a muscle-building supplement, but its uses go beyond that. This study looked at the potential for protein supplementation to improve sleep during a weight-loss diet.
Creatine, depression, and brain energetics
The human brain is a powerhouse, consuming tons of fuel to keep all those intricate neural connections going. Brain energetics may play a role in major depression, which makes creatine a potential adjunct to antidepressants and therapy.
The taurine-blood pressure connection
With well over half of Americans having either hypertension or prehypertension, effective supplements are a highly researched area. The amino-acid like compound taurine may be a safe and easy-to-obtain treatment option.
Is organic meat healthier?
Part of the allure of organic food is the potential for improved nutrition. But studies in the past have tended to focus on organic plant foods. This broadranging meta-analysis of 67 studies puts organic meat to the test
- Interview: Matt Smith MD
Vitamin D for MDD
Major depressive disorder (MDD) is a condition without many effective treatments, or at least treatments lacking side effects. Vitamin D has been linked to improved mood, and this trial tested it specifically for MDD