Scientific opinion on the tolerable upper intake level for manganese

Hazard classification of manganese salts based on animal neurotoxicity data: case study for specific target organ toxicity - repeated exposure (STOT-RE)

Specific Target Organ Toxicity - Repeated Exposure (STOT-RE) is a hazard class in both Globally Harmonized System and Classification, Labelling and Packaging (CLP) Regulation in the European Union (EU) legislation on hazard classification labeling and packaging of substances and mixtures. This legislation, used for the chemical safety assessment under the EU Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH), evaluates long-term exposure of chemicals on human or animals and designates three categories of classification - STOT RE 1 (potential to produce significant toxicity to humans); STOT RE 2 (presumed to be toxic to humans), or not classified. Human epidemiologic studies identified neurologic effects as the most sensitive adverse health effect following repeated manganese (Mn) exposure. However, there are inadequate human studies to assess the neurotoxicity and STOT-RE classification of the chloride, sulfate, and nitrate forms of Mn. This review summarizes peer-reviewed studies with original data identified from searches of PubMed and OECD studies submitted as part of the REACH information requirement. This review included peer-reviewed studies that exhibited a duration of ≥21 days, including oral or inhalation exposure, and reported neurobehavioral, neurochemical or neuropathologic outcomes. A total of 75, 6, and 0 investigations met the inclusion criteria for this review for the chloride, sulfate, and nitrate forms of Mn, respectively. Based upon retrieved data or read-across principles a proposed classification of these Mn salts, following repeated oral or inhaled exposure, is STOT RE 2, target organ, the brain.

Manganese exposure assessment in formula-fed infants in Israel

BACKGROUND

Proper nutrition is fundamental to the regular mental and physical development of infants, toddlers, and children. Overexposure to manganese (Mn) in infants has been correlated to various behavioral and neurological symptoms such as lower IQ, attention deficit hyperactivity disorder, and impairment in fine motor skills. The following study aims to evaluate exposure to Mn in formula-fed infants in Israel from birth to nine months of age.

METHODS

Over 200 infant formulas of multiple brands were sampled by the Israeli National Food Service, as part of a routine monitoring of levels of various nutritional components, including Mn. Data on levels of Mn in water was drawn from routine monitoring programs carried out by the Ministry of Health (MOH). Total energy requirements were calculated based on current infant weight and growth data collected over the past decade in MOH-operated family care centers. Dietary exposure was assessed for infants from birth to six months as the sum of Mn intake from infant formula and potable water. For infants aged seven-nine months, Mn intake from complementary feeding was assessed based on national surveys of feeding behavior in infants aged nine-twelve months.

RESULTS

Milk-based infant formula brands consistently demonstrated lower levels of Mn compared to other formulations. Almost half of the sampled formula brands exceeded regulatory tolerance to deviation from labelling of nutritional components. Though some variation in Mn concentrations is evident in water sources across Israel, the overall contribution of water to Mn intake is negligible given the high levels of desalination in Israel. Excessive Mn intake in formula-fed infants is evident across multiple formula brands.

CONCLUSIONS

When breastfeeding is not optional, milk-based formulas are the most suitable in terms of their relative contribution to Mn intake. Equating maximal levels of Mn in potable waters to levels set in EU and USA regulations is advisable. A greater regulatory tolerance for deviation from labelling of mineral content is advisable so as not to hinder importation of infant formulas.

Calling for a comprehensive risk assessment of selenium in drinking water

In the last two decades, research has elucidated that selenium, a trace element, has both nutritional and toxicological effects on human health, depending on its dose and chemical form. Recent animal, laboratory, and human studies have shown harmful effects of certain selenium species at specific exposure levels, prompting the need to reassess overall exposure to this element, including that occurring through drinking water, a primary source of inorganic selenium. Drinking water selenium standards worldwide are scarce and existing standards are inconsistent, likely because they have been informed by an incomplete and outdated assessment of the scientific evidence. Incorporating all the available human and laboratory evidence into a precautionary regulatory framework indicates that a drinking water limit of around 5 μg/L of selenium is needed to protect human health, i.e. with an uncertainty factor of 2 versus the lowest adverse effect level observed in human studies, and that higher values may pose unacceptable risks to humans. Despite the rarity of such high levels of selenium in underground and potable waters, coal mining and other sources of environmental pollution as well as geological factors may raise drinking water selenium content above a safe threshold, triggering the need to protect consumers, and to face challenging technological issues for selenium removal, currently under active investigation.

Exposure to Cadmium and Other Trace Elements Among Individuals with Mild Cognitive Impairment

BACKGROUND

A limited number of studies have investigated the role of environmental chemicals in the etiology of mild cognitive impairment (MCI). We performed a cross-sectional study of the association between exposure to selected trace elements and the biomarkers of cognitive decline.

METHODS

During 2019-2021, we recruited 128 newly diagnosed patients with MCI from two Neurology Clinics in Northern Italy, i.e., Modena and Reggio Emilia. At baseline, we measured serum and cerebrospinal fluid (CSF) concentrations of cadmium, copper, iron, manganese, and zinc using inductively coupled plasma mass spectrometry. With immuno-enzymatic assays, we estimated concentrations of β-amyloid 1-40, β-amyloid 1-42, Total Tau and phosphorylated Tau181 proteins, neurofilament light chain (NfL), and the mini-mental state examination (MMSE) to assess cognitive status. We used spline regression to explore the shape of the association between exposure and each endpoint, adjusted for age at diagnosis, educational attainment, MMSE, and sex.

RESULTS

In analyses between the serum and CSF concentrations of trace metals, we found monotonic positive correlations between copper and zinc, while an inverse association was observed for cadmium. Serum cadmium concentrations were inversely associated with amyloid ratio and positively associated with Tau proteins. Serum iron concentrations showed the opposite trend, while copper, manganese, and zinc displayed heterogeneous non-linear associations with amyloid ratio and Tau biomarkers. Regarding CSF exposure biomarkers, only cadmium consistently showed an inverse association with amyloid ratio, while iron was positively associated with Tau. Cadmium concentrations in CSF were not appreciably associated with serum NfL levels, while we observed an inverted U-shaped association with CSF NfL, similar to that observed for copper. In CSF, zinc was the only trace element positively associated with NfL at high concentrations.

CONCLUSIONS

In this cross-sectional study, high serum cadmium concentrations were associated with selected biomarkers of cognitive impairment. Findings for the other trace elements were difficult to interpret, showing complex and inconsistent associations with the neurodegenerative endpoints examined.

EFSA Panel on Genetically Modified Organisms (GMO), Casacuberta J, Barro F, Braeuning A, Cubas P, de Maagd R, Epstein MM, Frenzel T, Gallois J, Koning F, Messéan A, Moreno FJ, Nogué F, Savoini G, Schulman AH, Tebbe C, Veromann E, Gennaro A, Gil Gonzalez AB, Gómez Ruiz JÁ, Goumperis T, Kagkli DM, Lenzi P, Lewandowska A, Piffanelli P, Schoonjans R. Assessment of soy leghemoglobin produced from genetically modified Komagataella phaffii, under Regulation (EC) No 1829/2003 (application EFSA-GMO-NL-2019-162)

Genetically modified Komagataella phaffii strain MXY0541 was developed to produce soy leghemoglobin by introducing the LGB2 coding sequence encoding leghemoglobin from soybean (Glycine max). The molecular characterisation data and bioinformatic analyses do not raise any safety concerns. The safety of soy leghemoglobin as a food additive has already been assessed by the EFSA FAF Panel (EFSA-Q-2022-00031). The GMO Panel does not identify safety concerns regarding the toxicity and allergenicity of soy leghemoglobin protein as expressed in K. phaffii, and finds no evidence that the genetic modification would change its overall allergenicity. The GMO Panel concludes that the LegH Prep derived from genetically modified K. phaffii strain MXY0541 is safe for human consumption with regard to the effects of the genetic modification. No environmental impact from the use of this product is expected regarding the recombinant DNA sequences possibly remaining in the product. The GMO Panel concludes that LegH Prep from genetically modified K. phaffii strain MXY0541 is safe with respect to potential effects on human health and the environment at the proposed use and use level as far as the impact of the genetic modification is concerned. The overall conclusion is that the genetic modification does not lead to safety issues.

Manganese-derived biomaterials for tumor diagnosis and therapy

Manganese (Mn) is widely recognized owing to its low cost, non-toxic nature, and versatile oxidation states, leading to the emergence of various Mn-based nanomaterials with applications across diverse fields, particularly in tumor diagnosis and therapy. Systematic reviews specifically addressing the tumor diagnosis and therapy aspects of Mn-derived biomaterials are lacking. This review comprehensively explores the physicochemical characteristics and synthesis methods of Mn-derived biomaterials, emphasizing their role in tumor diagnostics, including magnetic resonance imaging, photoacoustic and photothermal imaging, ultrasound imaging, multimodal imaging, and biodetection. Moreover, the advantages of Mn-based materials in tumor treatment applications are discussed, including drug delivery, tumor microenvironment regulation, synergistic photothermal, photodynamic, and chemodynamic therapies, tumor immunotherapy, and imaging-guided therapy. The review concludes by providing insights into the current landscape and future directions for Mn-driven advancements in the field, serving as a comprehensive resource for researchers and clinicians.

EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA), Turck D, Bohn T, Castenmiller J, de Henauw S, Hirsch‐Ernst K, Knutsen HK, Maciuk A, Mangelsdorf I, McArdle HJ, Pentieva K, Siani A, Thies F, Tsabouri S, Vinceti M, Bornhorst J, Cubadda F, Dopter A, FitzGerald R, de Sesmaisons Lecarré A, das Neves Ferreira P, Fabiani L, Horvath Z, Matijević L, Naska A. Scientific opinion on the tolerable upper intake level for manganese

Following a request from the European Commission (EC), the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for manganese. Systematic reviews of the literature of human and animal data were conducted to assess evidence regarding excess manganese intake (including authorised manganese salts) and the priority adverse health effect, i.e. manganese-induced neurotoxicity. Available human and animal studies support neurotoxicity as a critical effect, however, data are not sufficient and suitable to characterise a dose-response relationship and identify a reference point for manganese-induced neurotoxicity. In the absence of adequate data to establish an UL, estimated background dietary intakes (i.e. manganese intakes from natural dietary sources only) observed among high consumers (95th percentile) were used to provide an indication of the highest level of intake where there is reasonable confidence on the absence of adverse effects. A safe level of intake of 8 mg/day was established for adults ≥ 18 years (including pregnant and lactating women) and ranged between 2 and 7 mg/day for other population groups. The application of the safe level of intake is more limited than an UL because the intake level at which the risk of adverse effects starts to increase is not defined.

Plain Language Summary on Scientific opinion on the tolerable upper intake level for manganese

This publication is linked to the following EFSA Journal article: https://efsa.onlinelibrary.wiley.com/doi/10.2903/j.efsa.2023.8413.