What Is a Safe Level of Manganese? Understanding Dietary and Environmental Guidelines

November 18, 2025 •

3 min read

According to the NIH Office of Dietary Supplements, the Tolerable Upper Intake Level (UL) for manganese in adults 19 years and older is 11 mg per day. Understanding what is a safe level of manganese is important for preventing health issues, as both deficiency and excessive intake can pose risks.

Quick Summary

A safe manganese intake depends on age and exposure source, including food and water. For healthy adults, daily intake should be between 1.8-2.3 mg, not exceeding 11 mg. Excessive inhalation or ingestion can lead to neurotoxicity, similar to Parkinson's disease.

Key Points

Tolerable Upper Limit: For adults, the maximum safe intake is 11 mg per day from all sources, including food, water, and supplements.
Dietary Intake: Most people get sufficient manganese from a balanced diet, making deficiency very rare.
Drinking Water Safety: Infants under six months require extra caution with manganese levels in drinking water used for formula.
Risk of Inhalation: Inhaling manganese dust in occupational settings poses a higher risk of toxicity than dietary intake.
Toxicity Symptoms: High manganese exposure, especially inhaled, can cause a neurological disorder called manganism with Parkinson's-like symptoms.

The Role of Manganese in Your Health

As a trace mineral, manganese is essential for human health, playing a key role in various metabolic processes. It is a vital component of several enzymes, including manganese superoxide dismutase (MnSOD), a powerful antioxidant that protects the body from cellular damage. Manganese is also crucial for bone formation, carbohydrate metabolism, and amino acid synthesis. Most people get enough manganese from their diet, making deficiency rare, but maintaining a proper balance is necessary for overall well-being. Excessive levels, particularly from non-food sources like drinking water or inhalation, can be harmful.

Dietary Manganese: Recommended and Upper Limits

For healthy individuals, nutritional guidelines provide an Adequate Intake (AI) to ensure sufficient consumption and a Tolerable Upper Intake Level (UL) to define a safe maximum to avoid toxicity.

Adequate Intake (AI) by Life Stage

The AI is the recommended daily amount based on scientific evidence for different age groups.

Infants (7–12 months): 0.6 mg
Children (1–3 years): 1.2 mg
Children (4–8 years): 1.5 mg
Boys (9–13 years): 1.9 mg
Girls (9–13 years): 1.6 mg
Adult Men (19+ years): 2.3 mg
Adult Women (19+ years): 1.8 mg
Pregnancy (14+ years): 2.0 mg
Lactation (14+ years): 2.6 mg

The Tolerable Upper Intake Level (UL)

The UL is the maximum daily intake from all sources (food, water, supplements) that is unlikely to cause adverse health effects for almost all healthy individuals.

Children (1–3 years): 2 mg
Children (4–8 years): 3 mg
Children (9–13 years): 6 mg
Teens (14–18 years): 9 mg
Adults (19+ years): 11 mg
Pregnant and Lactating Teens (14–18): 9 mg
Pregnant and Lactating Women (19+): 11 mg

Manganese in Drinking Water: Special Considerations

While food is the primary source of manganese for most people, contaminated drinking water can significantly increase intake, leading to health concerns, especially for infants.

Safe Drinking Water Guidelines

Various governmental bodies provide health advisory levels for manganese in drinking water. The U.S. Environmental Protection Agency (EPA) recommends a lifetime health advisory of 0.3 mg/L. For infants under six months, the Minnesota Department of Health recommends a stricter guideline of 100 µg/L (0.1 mg/L) or less if tap water is used for formula.

The Dangers of Manganese Overexposure

Manganese toxicity is a serious health risk, particularly from occupational inhalation exposure, though high oral intake from water and supplements can also be problematic. Inhaled manganese bypasses normal metabolic controls and can reach the brain more directly.

Symptoms of Toxicity (Manganism)

Chronic overexposure can cause a neurological disorder known as manganism, with symptoms resembling Parkinson's disease.

Headaches
Memory loss
Irritability
Difficulty walking and balance issues
Tremors and muscle rigidity
Changes in mood and short-term memory

High-Risk Groups

Certain individuals are more susceptible to manganese toxicity:

People with Chronic Liver Disease: Impaired liver function hinders the body's ability to excrete excess manganese via bile.
Individuals with Iron-Deficiency Anemia: Low iron levels can increase the body's absorption of manganese.

Dietary Sources and Manganese Balance

Most people can achieve adequate manganese intake through a balanced diet without needing supplements. The body regulates absorption and excretion to maintain stable levels when exposure is primarily from food.

Food Sources of Manganese

Whole grains, such as brown rice and oatmeal
Nuts, including pecans and hazelnuts
Legumes, like chickpeas and lentils
Leafy vegetables, such as spinach and kale
Beverages like tea
Shellfish, including mussels and clams

Manganese Deficiency (Extremely Rare)

Dietary manganese deficiency is uncommon, as the mineral is widely available in plant-based foods. In experimental settings, low intake has been linked to skin rashes and altered cholesterol levels. In animals, severe deficiency causes impaired growth and skeletal defects. A genetic disorder affecting a manganese transporter can also cause severe deficiency.

Comparison of Key Manganese Guidelines


Guideline Body	Adults AI (Men)	Adults UL (All)	Drinking Water Guideline (General)
US IOM/NIH	2.3 mg/day	11 mg/day	N/A (EPA Lifetime 0.3 mg/L)
European EFSA	3.0 mg/day	8 mg/day	N/A (WHO TDWI 0.025 mg/kg bw/day)

Conclusion

Maintaining a safe level of manganese is about finding the right balance. For the majority of people, this is easily achieved through a varied diet rich in whole grains, nuts, and vegetables. Awareness is most critical for vulnerable populations, such as infants, people with chronic liver conditions, and those with high exposure from drinking water or industrial inhalation. Always follow established upper limits, and if you have concerns about your intake, consult a healthcare professional. For more in-depth information on dietary minerals, visit the NIH Office of Dietary Supplements website.

Frequently Asked Questions

Excessive intake of manganese can lead to a condition called manganism, a neurological disorder with symptoms similar to Parkinson's disease. These symptoms include tremors, muscle rigidity, and difficulty walking. Inhalation is a particularly risky route of exposure.

Manganese toxicity from food is extremely rare because the body has mechanisms to regulate absorption and excretion. The primary risk of toxicity comes from high-dose supplements, contaminated drinking water, or industrial inhalation.

The EPA recommends a lifetime health advisory of 0.3 mg/L. Infants under six months are more sensitive and should not consume water or formula made with water containing more than 0.1 mg/L, according to some health departments.

People with chronic liver disease and individuals with iron-deficiency anemia should be particularly careful. The liver disease impairs manganese excretion, and iron deficiency increases absorption, making them more susceptible to toxicity.

Excellent food sources of manganese include whole grains like brown rice and oatmeal, nuts such as pecans and hazelnuts, legumes like soybeans, leafy greens like spinach and kale, and beverages like tea.

Dietary manganese deficiency is exceptionally rare in humans. The mineral is widespread in many common foods, and the body maintains stable levels effectively. Cases of deficiency are typically linked to specific genetic mutations.

Because clear deficiency symptoms are rare, an Adequate Intake (AI) is set instead of a Recommended Dietary Allowance (RDA) for most life stages. The AI is based on median manganese intakes observed in healthy populations.