What is the tolerable upper limit of manganese?

November 19, 2025 •

4 min read

While toxicity from food sources is rare, the official tolerable upper intake level (UL) of manganese for adults aged 19 and over is 11 mg per day. This is the maximum daily intake from all sources (food, water, supplements) that is considered unlikely to cause harmful health effects in nearly all individuals.

Quick Summary

The tolerable upper intake level (UL) for manganese in adults is 11 mg daily, established to prevent potential toxicity. Vulnerable groups, including those with liver disease or iron-deficiency anemia, should exercise extra caution with intake. Most dietary intake is safe, but excess from supplements or contaminated sources can be harmful.

Key Points

Adult Tolerable Upper Intake Limit: The UL for adults (19+ years) is 11 mg per day from all sources, including supplements and food.
Inhalation vs. Oral Risk: Inhaling manganese dust, common in occupational settings, poses a significantly higher toxicity risk than consuming it orally.
Manganism: Long-term excessive intake, particularly from non-food sources, can cause manganism, a neurological disorder with symptoms similar to Parkinson's disease.
High-Risk Individuals: People with chronic liver disease and those with iron-deficiency anemia are more susceptible to manganese toxicity and should monitor their intake carefully.
Dietary Source Safety: Toxicity from manganese in food is extremely rare for healthy individuals because the body has effective mechanisms for regulating absorption and excretion.
Varied UL by Age: Tolerable upper limits are lower for children and adolescents, reflecting their different physiological needs and vulnerabilities.

Defining the Tolerable Upper Intake Level (UL)

The Tolerable Upper Intake Level (UL) is a crucial metric in nutrition, representing the highest average daily intake of a nutrient that is likely to pose no risk of adverse health effects for almost all individuals in a specific life-stage group. For manganese, the UL is a safety guideline, particularly important for those consuming supplements or exposed to other manganese sources. The UL for adults (age 19+) was established by the U.S. National Academy of Medicine (formerly the Institute of Medicine) at 11 mg/day based on a review of human data showing no adverse effects at dietary intakes up to approximately 10.9 mg/day. For most healthy individuals, it is difficult to reach this level through food alone, making toxicity from dietary sources extremely uncommon.

Tolerable Upper Intake Levels by Age Group

The UL for manganese varies across different age groups, reflecting physiological differences and potential sensitivities. Infants have no established UL due to a lack of data and concerns about their ability to excrete excess manganese. All intake for infants should come from food or formula only.

Children (1–3 years): 2 mg per day
Children (4–8 years): 3 mg per day
Boys (9–13 years): 6 mg per day
Girls (9–13 years): 6 mg per day
Adolescents (14–18 years): 9 mg per day
Pregnant and Lactating Females (14–18 years): 9 mg per day
Adults (19+ years), including Pregnant and Lactating Females: 11 mg per day

The Dangers of Excessive Manganese Intake

Excessive intake of manganese can lead to a serious neurological disorder known as manganism. While the human body is generally effective at regulating manganese levels from dietary sources, this homeostatic mechanism can be overwhelmed by high-dose supplements, contaminated drinking water, or environmental exposure.

Symptoms of Manganism

Early symptoms of manganism can be subtle and include mood changes, irritability, headaches, and insomnia. As the condition progresses, more severe neurological issues manifest, often mimicking the symptoms of Parkinson's disease. These later symptoms can include:

Tremors
Muscle spasms
Poor balance and gait abnormalities
Difficulty with fine motor skills
Slurred speech

Inhalation Toxicity vs. Oral Intake

It is critical to distinguish between the risks from inhaling manganese (a significant occupational hazard for miners and welders) and ingesting it. Inhalation bypasses the body's normal regulatory mechanisms, posing a much higher and more direct risk of neurotoxicity. For the general population, oral toxicity is the primary concern, and it is far less common due to the body's efficient excretion process.

Factors Affecting Manganese Absorption and Toxicity

Not everyone is equally susceptible to manganese toxicity. Several factors can influence how the body absorbs and handles manganese:

Liver Disease: Individuals with chronic liver disease have a reduced ability to excrete manganese through bile, leading to its accumulation in the body and a higher risk of toxicity.
Iron Status: Iron and manganese compete for absorption via the same transport protein, DMT1. People with iron-deficiency anemia absorb significantly more manganese, increasing their risk if intake is high.
Water vs. Food: Manganese in drinking water may be more bioavailable than manganese found in food, meaning the body absorbs it more readily.
Age: Infants and the elderly may have increased sensitivity to high manganese levels.

Manganese Intake: Food vs. Supplements


Feature	Manganese from Food	Manganese from Supplements/Contaminated Water
Absorption/Bioavailability	Typically lower and more regulated by the body. Varies based on iron status and dietary factors.	Can be higher and less controlled, particularly in supplements and water sources.
Risk of Toxicity	Extremely low for healthy individuals due to the body's homeostatic controls.	Increases significantly at high doses, especially for vulnerable populations.
Source Regulation	The body naturally regulates the amount of manganese absorbed from food, with excess primarily excreted through bile.	Requires careful monitoring, especially if consuming doses near or above the UL.
Associated Risk	Low risk of toxicity; dietary sources are considered safe within normal eating patterns.	Increased risk of neurotoxicity if intake exceeds the UL, especially over the long term.

How to Safely Manage Manganese Intake

To ensure safe manganese intake, prioritize obtaining it from a balanced diet rich in whole foods. Good sources include:

Whole grains (e.g., brown rice, oatmeal)
Nuts (e.g., hazelnuts, pecans)
Legumes (e.g., chickpeas, lentils)
Leafy greens (e.g., spinach, kale)
Tea
Shellfish (e.g., mussels, oysters)

For most people, a varied diet is sufficient to meet their manganese needs without risk of excess. If you are considering taking a supplement containing manganese, especially a high-dose one, it is best to consult a healthcare provider to ensure it is appropriate for your individual health status. People with conditions like liver disease or iron-deficiency anemia should be particularly careful and seek professional guidance.

Conclusion

The tolerable upper limit of manganese for adults is 11 mg daily, a safe threshold that is rarely exceeded through diet alone. However, the UL provides an important guideline, especially for those considering supplements or living in areas with contaminated water. While manganese is a vital nutrient for bone health and metabolic function, excessive intake can lead to serious neurological issues. By understanding the sources, absorption factors, and the groups most at risk, individuals can safely manage their intake and protect their health. When in doubt, prioritize whole food sources and consult a healthcare professional before taking supplements, especially if you have underlying health conditions.

To explore more details about dietary reference intakes, consult the National Institutes of Health (NIH) Office of Dietary Supplements website.

Frequently Asked Questions

The primary risk of consuming excessive manganese over a long period is the development of manganism, a neurological condition with symptoms like tremors, muscle spasms, and poor balance that resemble Parkinson's disease.

Manganese supplements are generally safe when taken below the Tolerable Upper Intake Level (UL) of 11 mg daily for adults. However, certain groups, such as those with liver disease or iron deficiency, should be cautious and consult a healthcare provider before use.

It is extremely unlikely for a healthy person to experience manganese toxicity from consuming food alone. The body is adept at regulating and excreting excess manganese obtained from dietary sources.

Early signs of manganese toxicity can be subtle and include mood changes, irritability, headaches, insomnia, and loss of appetite. These symptoms can worsen over time, leading to more severe neurological issues.

Manganese in drinking water is absorbed more readily by the body than manganese from food. High levels in contaminated water, especially if consumed long-term, can pose a greater risk of toxicity.

Individuals with chronic liver disease, who cannot excrete manganese efficiently, and those with iron-deficiency anemia, who absorb more manganese, are at a higher risk of developing toxicity.

Some plant-based diets, such as those high in whole grains, nuts, and legumes, may have a higher manganese content than average Western diets. While toxicity from food is rare, those with underlying risk factors like liver disease should be aware of their total intake.