Nutritional Requirements for Manganese

Abstract

Manganese (Mn) is a ubiquitous trace mineral that is essential for living organisms. This mineral is a cofactor of enzymes such as superoxide dismutase and arginase. It assumes a significant role in the metabolism of carbohydrates, amino acids and cholesterol, the formation of bone, digestion, and development. Food sources include whole grains, cereals, green leafy vegetables, nuts, and tea. Approaches to assess Mn requirements include metabolic balance, blood levels, and response of biomarkers. In the United States, the adequate intake (AI) of Mn is 1.8 and 2.3 mg day−1 for women and men, respectively. Negative balance has been reported in numerous studies, where Mn intake was greater than the AI; thus, the adequacy of current dietary recommendations is unclear. Factors that influence Mn requirements include life stage and gender, bioavailability (fiber, phytates, mineral interactions, polyphenolic compounds), and international considerations. Deficiency of Mn has been associated with adverse health conditions including dermatitis, osteoporosis, dyslipidemia, diabetes, metabolic syndrome, hypertension, epilepsy, cancer, asthma, problems with cognitive function, and poor birth outcomes. Toxicity of Mn may be a potential problem with contaminated drinking water, parenteral nutrition, individuals with hepatic dysfunction, and soy formula-fed infants. An understanding of Mn nutrient requirements is important for achievement of optimal health.

Dietary Manganese Exposure in the Adult Population in Germany—What Does it Mean in Relation to Health Risks?

“…Indeed, several dietary components have been reported to modify manganese bioavailability under experimental conditions. For example, bioavailability of manganese was reduced in the presence of dietary fiber, phytate, copper, and calcium, whereas bioavailability was elevated in the presence of zinc . This suggests that bioavailability of manganese from vegetarian diets that are rich in phytate and fiber might be reduced compared to those from omnivorous diets.…”

“…It acts as a component of metalloenzymes, such as arginase, pyruvate carboxylase, and manganese‐dependent superoxide dismutase. In addition, it is an activator for a large number of hydrolases, kinases, decarboxylases, and transferases . Therefore, an adequate manganese supply is thought to be important for several physiological processes, for example, development and reproduction, formation of bone and cartilage, wound healing, proper immune function and regulation of cellular energy, and blood glucose .…”

“…As the dietary manganese intake is the major route of exposure for the general population, the latter finding raises concern whether there might be an association between high manganese intakes from the total diet and detrimental health effects. In particular, plant‐based food products, such as whole grain, brown rice, vegetables, nuts, and tea are known to be important contributors to the dietary manganese intake, whereas meat and white flour generally contain small amounts of manganese . In addition, manganese‐containing food supplements may also contribute to the daily manganese exposure.…”

Manganese in Health and Disease

“…Thus, Mn deficiencies, although not frequently reported in humans, may result in several biochemical and structural defects [35,99,100]. Accordingly, taking into account the Mn-dependent enzymatic processes, it is clear that inadequate daily supply of this metal may be associated with a variety of health repercussions [31,32].…”

Comparative biochemical profile of protein-rich products obtained from industrial rapeseed meal

“…Although fiber is often implied to negatively affect zinc bioavailability, more precise studies involving reduction of concomitant antinutrient factors (Barbro et al, 1985) as well as experiments on pure fiber components such as α-cellulose (Turnlund et al, 1984) suggested little or no inhibitory effect of fiber on zinc absorption. However, further investigation should be performed to evaluate the influence of the high fiber content in ASP on manganese bioavailability (Freeland-Graves et al, 2015). If needed, a decrease in fiber content could be achieved by enzymatic or chemical decomposition.…”