The estimated daily manganese intake of Korean children aged 11-12

Manganese Pollution and Its Remediation: A Review of Biological Removal and Promising Combination Strategies

Manganese (Mn), as a cofactor of multiple enzymes, exhibits great significance to the human body, plants and animals. It is also a critical raw material and alloying element. However, extensive employment for industrial purposes leads to its excessive emission into the environment and turns into a significant threat to the ecosystem and public health. This review firstly introduces the essentiality, toxicity and regulation of Mn. Several traditional physicochemical methods and their problems are briefly discussed as well. Biological remediation, especially microorganism-mediated strategies, is a potential alternative for remediating Mn-polluted environments in a cost-efficient and eco-friendly manner. Among them, microbially induced carbonate precipitation (MICP), biosorption, bioaccumulation, bio-oxidation are discussed in detail, including their mechanisms, pivotal influencing factors along with strengths and limitations. In order to promote bioremediation efficiency, the combination of different techniques is preferable, and their research progress is also summarized. Finally, we propose the future directions of Mn bioremediation by microbes. Conclusively, this review provides a scientific basis for the microbial remediation performance for Mn pollution and guides the development of a comprehensive competent strategy towards practical Mn remediation.

Macrominerals and Trace Minerals in Commercial Infant Formulas Marketed in Brazil: Compliance With Established Minimum and Maximum Requirements, Label Statements, and Estimated Daily Intake

Infant formulas are the main nutritional source for infants when breastfeeding is not possible or recommended. The daily need for specific nutrients, such as essential minerals, in early stages of a child's life is high because of rapid infant growth and development, which impose metabolic flux increases on these pathways to support growth, physical activity, and defense against infections. In this context, this research aimed to determine macromineral and trace mineral contents in starting (phase 1) and follow-up (phase 2) infant formulas marketed in Brazil (n = 30) by inductively coupled plasma-mass spectrometry, calculate estimated daily intakes, and compare them to reference values regarding adequate intake and tolerable upper intake levels. The highest concentrations of macrominerals were observed in Ca, K, P, and Na, and trace minerals in Fe, Zn, Mn, and Cu. Certain homogeneity only to trace mineral contents was observed when analyzing inter-batch values from same manufacturers. In general, all phase 1 and phase 2 infant formula brands and batches met or exceeded Fe, Zn, Cu, Mo, and Se contents when compared to maximum limits established by Codex Alimentarius. In addition, Zn contents in eight phase 1 and in four phase 2 infant formulas were above the contents established by the tolerable upper intake level for children aged 0–6 and/or 7–12 months, respectively. These findings highlight the need to expand regular infant formula inspection concerning nutritional quality, as some composition aspects of these foods must be improved to follow international guidelines, since ideal requirements for infant formula composition, quality, and safety interfere in child development and adult health.

Dietary manganese and type 2 diabetes mellitus: two prospective cohort studies in China

AIMS/HYPOTHESIS

The association between dietary Mn and type 2 diabetes is unclear. We aimed to elucidate whether dietary Mn is associated with type 2 diabetes, to investigate whether this association is independent of dietary total antioxidant capacity (TAC) and to explore the underlying mechanisms in their association.

METHODS

Two prospective cohorts of 3350 and 7133 Chinese adults (20-74 years old) were enrolled including, respectively, 244 and 578 individuals newly diagnosed with type 2 diabetes, with mean values of 4.2 and 5.3 years of follow-up. Cox's proportional-hazards regression and linear regression were performed to investigate the association between dietary Mn and type 2 diabetes (diagnosed by OGTT) or HbA_lc and to analyse the joint association between dietary Mn and TAC. Restricted cubic spline (RCS) regression was applied to the non-linear association between dietary Mn and incidence of type 2 diabetes. Mediation analysis was applied to explore potential mediators in their association in a subgroup of 500 participants.

RESULTS

Dietary Mn intakes were 4.58 ± 1.04 and 4.61 ± 1.08 (mean ± SD) mg/day in the two cohorts. Dietary Mn was inversely associated with type 2 diabetes incidence and HbA_lc concentration in both cohorts (p_trend < 0.01 and <0.01 for type 2 diabetes, and p_trend < 0.01 and =0.02 for HbA_lc, respectively, in each cohort) independent of TAC, adjusted for age, sex, BMI, tobacco use, alcohol consumption, physical activity, diabetes inheritance, total energy, carbohydrate, total fatty acids, fibre, calcium, Mg, hypertension, hyperlipidaemia, and impaired glucose tolerance or FBG (all at baseline). Their inverse association was stronger in the presence of diets with high, compared with low, TAC. In RCS, intakes of >6.01 and 6.10-6.97 mg/day were associated with a significantly lower type 2 diabetes incidence in the two respective cohorts. Mediation analysis showed that high plasma Mn and low oxidative stress (increased Mn superoxide dismutase and decreased 8-hydroxydeoxyguanosine) contributed to the association between dietary Mn and both type 2 diabetes and HbA_lc.

CONCLUSIONS/INTERPRETATION

Dietary Mn was inversely associated with type 2 diabetes independently of TAC. In addition, this association was stronger in a high- rather than low-TAC diet. Plasma Mn and oxidative stress were mediators in the association between dietary Mn and type 2 diabetes. Future studies on absolute Mn intake should be conducted to study the potential non-linearity and optimal levels of dietary Mn and type 2 diabetes.

Hypomagnesemia and its relation with chronic low-grade inflammation in obesity

Introduction:

The accumulation of visceral fat in obesity is associated with excessive production of proinflammatory adipokines, which contributes to low-grade chronic inflammation state. Moreover, the literature has shown that mineral deficiency, in particular of magnesium, has important role in the pathogenesis of this metabolic disorder with relevant clinical repercussions.

Objective:

To bring updated information about the participation of hypomagnesemia in the manifestation of low-grade chronic inflammation in obese individuals.

Method:

Articles published in PubMed, SciELO, LILACS and ScienceDirect, using the following keywords: "obesity," "magnesium" and "low grade inflammation."

Results:

Scientific evidence suggests that magnesium deficiency favors the manifestation of low-grade chronic inflammation in obese subjects.

Conclusion:

From literature data, it is evident the participation of magnesium through biochemical and metabolic reactions in protecting against this metabolic disorder present in obesity.

Dietary intake of manganese and the risk of the metabolic syndrome in a Chinese population

Animal studies have suggested that Mn might be associated with some components of the metabolic syndrome (MetS). A few epidemiological studies have assessed dietary Mn intake and its association with the risk of the MetS and its components among Chinese adults. In this study, we assessed daily dietary Mn intake and its relationship with MetS risk among Chinese adults in Zhejiang Province using data from the 5th Chinese National Nutrition and Health Survey (2010–2012). A total of 2111 adults were included. Dietary Mn intake was assessed using 3-d 24-h dietary recalls; health-related data were obtained by questionnaire surveys, physical examinations and laboratory assessments. The mean intake of Mn was 6·07 (sd 2·94) mg/d for men (n 998) and 5·13 (sd 2·65) mg/d for women (n 1113). Rice (>42 %) was the main food source of Mn. The prevalence of the MetS was 28·0 % (590/2111). Higher Mn intake was associated with a decreased risk of the MetS in men (Q4 v. Q1 OR 0·62; 95 % CI 0·42, 0·92; P_trend=0·043) but an increased risk in women (Q4 v. Q1 OR 1·56; 95 % CI 1·02, 2·45; P_trend=0·078). In addition, Mn intake was inversely associated with abdominal obesity (P_trend=0·016) and hypertriacylglycerolaemia (P_trend=0·029) in men, but positively associated with low HDL-cholesterol in both men (P_trend=0·003) and women (P_trend<0·001). Our results suggest that higher Mn intakes may be protective against the MetS in men. The inverse association between Mn intake and the MetS in women might be due to the increased risk for low HDL-cholesterol.

A pilot duplicate diet study on manganese, selenium and chromium intakes in institutionalised children and adolescents from Guatemala

Hidden hunger occurs in the presence of an otherwise nutritionally or energetically appropriate diet that is deficient in essential vitamins and minerals. Guatemala has the highest rate of child malnutrition in Latin America and the prevalence of hidden hunger is high. The aim of this study was to determine the Mn, Se and Cr dietary intakes in Guatemalan institutionalised children (4-14 years), a population group at high risk of mineral deficiency. For this purpose, the contents of Mn, Se and Cr were analysed in a duplicate diet (for 7 consecutive days) by electrothermal atomisation-atomic absorption spectrophotometry following acid digestion. Mn, Se and Cr intakes from the duplicate diets were in the range of 1·3-2·31 mg/d, 58·7-69·6 µg/d and 6·32-27·57 µg/d, respectively. Mn and Cr values were below current recommended daily intakes. A cereal- and legumes-based diet is habitually consumed by this population. Local vegetables, fruits and nutritional supplements are included daily, but the consumption of fish, meat, eggs and dairy products is very infrequent or negligible. Mean daily energy intake from the 7-d diet was 8418·2 kJ (2012 kcal), with a macronutrient energy distribution of carbohydrates 69·4 %, proteins 12·3 % and fats 18·3 %. Correlations between Mn, Se and Cr intakes and energy and other nutrient intakes were also evaluated. The present findings will help establish new nutritional strategies for this and similar population groups.