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Louie Helm of Rockstar Research Magazine blog argues that that the human body doesn't need Chromium nor Manganese and, therefore, there is no need to have them in multivitamin supplements.
This leaves Chromium and Manganese as the most commonly recommended minerals that still make their way into most multivitamins despite having no proposed mechanisms of action.
Is that an accurate reflection of the current science?
Despite popular claims in nutritional literature, there is no definitive evidence that chromium (Cr) is an essential element for human or animal nutrition.
Chromium plays a role in insulin physiology, and severe chromium deficiency can lead to insulin resistance. Chromium supplementation may be beneficial in rare cases of prolonged total parental nutrition when standard chromium supplementation is lacking[6]. Despite the lack of sufficient evidence that chromium supplementation improves glycemic control[28,29], chromium is still widely marketed as an effective supplement for improving glycemic control in patients with type 2 diabetes.
Based on the animal studies, our results suggest that blood Cr(III) concentrations as high as 480–580 μg/L are not associated with any responses. For each of the three health endpoints considered in this analysis (hematological, hepatic, and renal) no adverse effects were observed below 3,700 μg/L. Some hematological responses were observed at 3,700 μg/L, and adverse effects clearly occurred at 7,500 μg/L. These findings can be used to assess potential health risks to individuals with elevated blood Cr(III) concentrations.
Chromium can play an important role in human physiology, but if you do not have severe chromium deficiency (which is rare) you should not consume chromium nutritions, because you don't need it, and because it can cause hepatic and renal damage.
Manganese superoxide dismutase (MnSOD) is a critical component of the antioxidant system tasked with protecting the oxidant-sensitive mitochondrial compartment from oxidative stress. Since global knockout of MnSOD results in significant cardiac and neuronal damage leading to early postnatal lethality, this approach has limited use for studying the mechanisms of oxidant stress and the development of disease in specific tissues lacking MnSOD.
For humans manganese is both an essential trace element and, at higher doses, a toxic metal. Due to the ubiquitous occurrence of manganese in foodstuff, in industrial countries daily dietary uptake is higher as compared to the estimated daily requirement. Therefore manganese deficiency is extremely rare. In contrast chronic manganese toxicity, affecting primarily the central nervous system, is more prevalent. Thus manganese occupational and dietary overexposure has been shown to cause progressive, permanent, neurodegenerative damage, resulting in syndromes similar to idiopathic Parkinson's disease. To date modes of manganese neurotoxic action are poorly understood and in most studies oxidative stress is postulated as the underlying mechanism. The present study searched on the cellular level for a molecular mechanism behind manganese-induced neurotoxicity and investigated bioavailability, cytotoxicity and genotoxicity of MnCl2, as well as its impact on the DNA damage response in human cells (HeLa S3) in culture.
Manganese certainly plays an important role in human physiology, but if you don't have manganese deficiency (which is rare either), then you should not consume manganese nutritions, because too much manganese can cause neural damage. It has a small genotoxicity either, so huge amounts in long term may cause cancer, but I guess you would die before that because of the the neural damage. ;-)
