What is Manganese?
Manganese is a trace mineral, meaning the human body needs it in very small amounts to function properly. Despite its low requirement, it is an essential nutrient that plays a pivotal role as a cofactor for many enzymes. These enzymes are involved in critical biological processes, including carbohydrate, amino acid, and cholesterol metabolism; bone formation; antioxidant defense; and reproductive function. The body stores most of its manganese in the bone, liver, kidneys, and pancreas.
The Rarity of Dietary Manganese Deficiency
For the general population, getting enough manganese from diet is typically not an issue. The mineral is widely available in plant-based foods, and the body has a robust system for regulating its absorption. When dietary intake is low, the body's absorption becomes more efficient to compensate. This homeostatic control is why manganese deficiency in healthy people is so rare. The concern, however, shifts to individuals with compromised health or specific genetic predispositions.
Which Disease is Caused Due to the Deficiency of Manganese?
While a single disease isn't exclusively caused by low manganese, a deficiency can contribute to or exacerbate several health problems. Most evidence comes from severe, induced deficiencies in animal models or from rare human cases involving genetic disorders or long-term parenteral nutrition.
Potential health implications of manganese deficiency include:
- Metabolic Disorders: Manganese is crucial for activating enzymes that regulate the metabolism of carbohydrates, fats, and cholesterol. A deficiency can impair these processes, potentially leading to impaired glucose tolerance, a pre-diabetic state. Some studies have suggested a link between low manganese levels and type 2 diabetes, though the connection remains unclear and requires more research.
- Bone and Skeletal Abnormalities: As a cofactor for enzymes essential for cartilage and bone formation, insufficient manganese can hinder proper skeletal development. Animal studies show that manganese deficiency can result in poor bone growth, demineralization, and skeletal defects such as enlarged joints and a curved spine. In humans, a child on long-term intravenous feeding without manganese developed bone demineralization and stunted growth that improved with supplementation.
- Reproductive Issues: Animal research has demonstrated that low manganese intake can lead to reproductive problems. A study using data from the BioCycle Study found that low dietary manganese in women was associated with an increased risk for sporadic anovulation, a disruption of the menstrual cycle. In male animals, deficiency has caused testicular degeneration and impaired sperm quality.
- Skin and Connective Tissue Problems: Manganese is necessary for synthesizing collagen, a key component of skin and connective tissues. Reports from limited human studies and animal models suggest that low levels can lead to skin rashes and impaired wound healing.
- Neurological Dysfunction: Manganese plays a role in neurotransmitter synthesis. A deficiency can manifest in neurological symptoms, such as altered mood, irritability, and potentially, in rare cases, an increased susceptibility to seizures.
Genetic Disorders of Manganese Metabolism
Perhaps the clearest evidence of disease resulting from manganese deficiency comes from inherited conditions affecting manganese transporters. For example, mutations in the SLC39A8 gene, which helps transport manganese into cells, can cause a deficiency syndrome.
Symptoms of SLC39A8 deficiency include:
- Neurodevelopmental delay
- Seizures
- Dystonia (involuntary muscle contractions)
- Short stature
- Congenital disorder of glycosylation (due to manganese's role as an enzyme cofactor in glycosylation)
In these specific genetic cases, manganese supplementation can often improve clinical symptoms and normalize biochemical findings.
What is the Difference Between Deficiency and Toxicity?
While deficiency is rare, manganese toxicity is a more common concern, particularly in occupational settings or from high-dose supplementation. It is important to understand the contrasting effects.
| Feature | Manganese Deficiency (Rare) | Manganese Toxicity (More Common) |
|---|---|---|
| Cause | Primarily from rare genetic mutations or medical conditions affecting absorption; very rarely from diet. | Long-term exposure to inhaled manganese dust (e.g., welders) or high-dose supplementation. |
| Key Effect | Impaired enzyme function leading to metabolic disturbances, poor bone development, and reproductive issues. | Neurodegeneration and neurological damage, sometimes called manganism. |
| Neurological Symptoms | Mood changes, cognitive issues, and increased risk of seizures in genetic cases. | Parkinson's-like symptoms, including tremors, difficulty walking, and muscle spasms, as well as aggression and psychiatric issues. |
| Impact | Stunted growth, metabolic disruption, skin rashes, and reproductive problems. | Can lead to irreversible nerve damage if left untreated. |
Conclusion
While a severe dietary manganese deficiency is exceptionally uncommon in healthy individuals, its role as a cofactor for numerous vital enzymes means that insufficient levels can lead to a cascade of problems. These range from metabolic dysfunction and poor bone formation to reproductive issues and neurological symptoms, especially in cases with underlying genetic mutations or medical conditions affecting nutrient absorption. Maintaining adequate manganese status is important, but for most people, this is achieved through a balanced diet rich in whole grains, nuts, and leafy greens. For those with specific risk factors, consulting a healthcare professional for diagnosis and potential supplementation is crucial to prevent the health complications associated with low manganese levels. For more information, the National Institutes of Health provides a comprehensive resource on manganese health facts(https://ods.od.nih.gov/factsheets/Manganese-HealthProfessional/).
