Manganese (as Manganese Amino Acid Chelate, Manganese Citrate)
Also known as: Manganese bisglycinate chelate, manganese citrate, Chelated manganese, manganese glycinate, manganese(II) citrate
Overview
Manganese is an essential trace mineral that functions as a cofactor for several metalloenzymes, including Mn-superoxide dismutase (MnSOD), arginase, and pyruvate carboxylase. These enzymes are crucial for antioxidant defense, amino acid metabolism, and glucose production, respectively. Dietary sources of manganese include whole grains, legumes, and nuts. Manganese is available in various forms, including chelated forms like manganese bisglycinate chelate and manganese citrate, which are designed to enhance bioavailability compared to inorganic salts. However, research specifically on chelated forms is still limited, with most human studies focusing on manganese in general. Manganese plays a vital role in various physiological processes, but supplementation should be approached cautiously due to its narrow safety margin.
Benefits
Manganese's primary benefits revolve around its role as a cofactor for essential enzymes. MnSOD provides antioxidant support, with activity showing a dose-dependent response to manganese intake in controlled trials. Observational data suggests a potential association between manganese and bone mineral density, although the evidence is primarily mechanistic. While some studies suggest a non-linear relationship between manganese and glucose metabolism, a meta-analysis found no statistically significant reduction in metabolic syndrome risk. Emerging preclinical evidence suggests a role in neurotransmitter synthesis. Overall, while manganese is essential, the clinical significance of supplementation remains limited, and more research is needed to confirm its benefits.
How it works
Manganese absorption is influenced by the form in which it is ingested. Chelated forms, such as manganese bisglycinate, bypass competitive inhibition with other minerals like iron and calcium in the duodenum, potentially enhancing absorption. Once absorbed, manganese is bound to transferrin and albumin for distribution throughout the body, with higher concentrations found in mitochondria-rich tissues. Excretion primarily occurs through the biliary route, with some enterohepatic recirculation. At the molecular level, manganese activates glycosyltransferases, hydrolases, and kinases through divalent cation interactions, playing a crucial role in various enzymatic reactions.
Side effects
Manganese supplementation is generally considered safe at recommended dosages, but excessive intake can lead to adverse effects. The European Food Safety Authority (EFSA) has established an upper limit (UL) of 11 mg/day. Common side effects are not typically reported below this level. However, chronic exposure to doses exceeding 15 mg/day has been associated with neurotoxicity, including extrapyramidal symptoms. Manganese may interact with certain medications, potentially reducing the efficacy of levodopa and potentiating the effects of neuroleptics. Individuals with hepatic impairment or manganese transporter defects may be contraindicated for manganese supplementation. It is crucial to adhere to recommended dosages and consider potential interactions and contraindications to minimize the risk of adverse effects.
Dosage
The recommended dosage for both chelated and citrate forms of manganese typically ranges from 2 mg to 5 mg daily, with a maximum upper limit of 11 mg per day. It is advisable to take manganese supplements with meals to reduce the potential for gastrointestinal irritation. Vitamin K and zinc may act as cofactors, synergistically supporting bone metabolism and enzyme function, respectively. Dosages may vary based on individual needs and specific health conditions, but it is essential to stay within the established upper limit to avoid potential toxicity. Supplementation is generally not necessary for individuals consuming a balanced Western diet unless a deficiency is confirmed.
FAQs
Is chelated manganese safer than other forms?
There is no definitive evidence to suggest that chelated manganese is inherently safer than other forms. However, it may be better tolerated at higher doses due to potentially improved bioavailability and reduced gastrointestinal side effects.
How long until effects appear?
Biochemical changes, such as increased MnSOD activity, may be observed within weeks of supplementation. However, clinical outcomes may require several months to become apparent, and the evidence for these outcomes remains inconclusive.
Who needs supplementation?
Manganese supplementation is rarely necessary for individuals consuming a typical Western diet. Supplementation should be reserved for cases of confirmed deficiency, which are uncommon.
Research Sources
- https://pubmed.ncbi.nlm.nih.gov/35215474/ – A systematic review and meta-analysis of 12 studies found no significant association between dietary or serum manganese biomarkers and metabolic syndrome risk. The study's limitations include the predominance of cross-sectional designs and heterogeneity in exposure assessment, leading to a moderate quality rating.
- https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2020.6001 – The EFSA safety assessment established an upper limit of 11 mg/day for manganese based on changes in lymphocyte MnSOD activity. The assessment relies on data from a 1992 human trial and provides a comprehensive risk assessment, earning a high-quality rating.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10704406/ – This regulatory assessment compared the bioavailability of chelated manganese forms to inorganic salts, finding comparable tissue deposition. The study is limited by its reliance on animal model data and industry-submitted studies, resulting in a moderate quality rating.
- https://lpi.oregonstate.edu/mic/minerals/manganese – This Linus Pauling Institute article provides a general overview of manganese, its functions, dietary sources, and potential health benefits. It serves as a comprehensive resource for understanding the role of manganese in human health.
- https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2013.3324 – This EFSA document provides scientific opinions on the safety and efficacy of manganese compounds added to food. It includes evaluations of various manganese sources and their potential impact on human health.
