The authors of this research study investigated the association between environmental exposure to manganese and cognitive performance. Their research populations are from two communities in Gauteng province, South Africa. One community with long term environmental Mn exposure from the Meyerton community. They are located within 5 km of one of the world’s largest Mn smelters. Smelting is when heat is applied to ore, to extract a base metal. Metalloy’s is the largest producer of manganese ferroalloys in South Africa. Its smelter complex is based in Meyerton in Gauteng Province which has been in operation since 1951. [1] The reference community live in Ethembalethu, a community located 70 km northwest of Meyerton, with no nearby Mn smelting or mining operations.
Research participants were current residence in one of the above communities and age less than or equal to 40. The participants were not selected due to health, length of residence or exposure. Meyerton had 732 participants and Ethembalethu had 100. The median age of participants was 51 years (49 in Meyerton and 55 in Ethembalethu). The majority of participants in both communities were female. The Meyerton community was used as an indicator of Mn airborne exposure status. The researchers measured airborne concentrations in both communities for several months. They used samples of hair and toenail clippings as biomarkers.
Researchers performed three cognitive tests in each community, reading and different cognitive IQ verbal and nonverbal tests. They assessed cognition using the Go-No-Go (Barch et., 1997; Braver et al., 2001) and the Digit Span (Wechsler, 1987). After testing they age scaled the results of the tests. On average the Meyerton residence had lower cognitive scores than Ethembalethu residence for all three cognitive tests. This study provides the evidence of an association between environmental Mn exposure and performance on cognitive functioning. [2]
If one of my clients ask me about this study, I would communicate the importance of providing your body with the right amount of manganese for overall health.
Adequate manganese intake-
Important to overall health
Cognitive health
Our bodies need a very small amount
Helps enzymes work properly
Helps metabolize cholesterol, carbohydrates and protein
Aids in fighting free radicals
Lowers blood sugar
Promotes bone health
Inadequate manganese intake-
Cognitive decline
Diabetes
Osteoporosis
Epilepsy
Seizures
Poor bone health
Manganese is essential and vital to health. It is stored in the bones, kidneys and pancreas and is a trace mineral, which means bodies need a very small amount of it. The human body needs manganese for many important functions. Manganese helps promote normal brain and nerve function, helps enzymes carry out their functions in the body and it helps with the metabolism of cholesterol, carbohydrates and protein. Also, manganese aids in fighting the damaging effects of free radicals, good for lowering sugar and is essential for bone health. Although rare, manganese deficiency may happen if people do not get enough of the mineral in the food they consume. Inadequate manganese intake can lead to diabetes, osteoporosis, epilepsy, seizures and skeletal and postural abnormalities. [3]
The body does require manganese to function properly, large amounts can cause manganese toxicity. Even though it is essential in trace amounts, manganese is considered a heavy metal. There are a variety of ways to acquire manganese. Manganese can be acquired oral and through the respiratory system. It is found in foods such as nuts, seeds, tea, wholegrains and green leafy vegetables. Too much of manganese can negatively affect health, especially brain health.
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[1] Journal of the Southern African Institute of Mining and Metallurgy. (n.d.).
[2] Racette BA, Nelson G, Dlamini WW, Hershey T, Prathibha P, Turner JR, Checkoway H, Sheppard L, Searles Nielsen S. Environmental manganese exposure and cognitive control in a South African population. Neurotoxicology. 2022 Mar; 89:31-40. doi: 10.1016/j.neuro.2022.01.004. Epub 2022 Jan 6. PMID: 34999155.
[3] Hsph.harvard.edu. .
Accessed December 2, 2022.
