Manganese Requirements and Dietary Sources

Dietary manganese is a trace mineral found in tiny amounts in the human body, mostly in the bones, liver, pancreas, and kidneys. It's necessary for the production of several enzymes and antioxidants that fight free radical damage and aid in carbohydrate and lipid metabolism. Manganese is also needed for a healthy nervous system and brain function.

The good news is that you can get enough manganese each day by eating a typical diet. Supplementation beyond the usual recommended daily intake is not necessary, and taking too many manganese supplements could lead to toxicity.

Dietary manganese is found in nuts, seeds, legumes (like lentils and dry beans), whole grains (such as wheat and oats), and pineapples. You will also get manganese from animal sources. If you are a vegetarian or you eat a typical Western-type diet, you are already getting more than the dietary reference intake each day. Manganese is stable in foods when cooked.

Examples of foods that supply you with a significant portion of your daily needs per serving include:

• Pineapple (raw pineapple or pineapple juice)
• Pecans, almonds, hazelnuts, and peanuts
• Chia seeds, sesame seeds, flaxseeds, sunflower seeds, pumpkin seeds
• Spinach, Swiss chard, collard greens, kale, mustard greens, turnip greens
• Oats
• Brown rice
• Raspberries, strawberries
• Summer squash
• Soybeans, tofu, tempeh
• Garbanzo beans, lima beans, navy beans, pinto beans, pinto beans, black beans
• Seafood such as mussels, clams, and crayfish
• Whole wheat bread
• Quinoa
• Spices such as cloves, cinnamon, black pepper, turmeric

The Health and Medicine Division of National Academies of Sciences, Engineering, and Medicine determines the dietary reference intakes (DRIs) for vitamins and minerals. The DRIs are based on the nutritional needs of the average healthy person. The DRIs for manganese are based on age and sex. Women who are pregnant or breastfeeding need just a little more.

Females

• 1 to 3 years: 1.2 milligrams per day
• 4 to 8 years: 1.5 milligrams per day
• 9 to 18 years: 1.6 milligrams per day
• 19 years and older: 1.8 milligrams per day
• Women who are pregnant: 2.0 milligrams per day
• Women who are breastfeeding: 2.6 milligrams per day

Males

• 1 to 3 years: 1.2 milligrams per day
• 4 to 8 years: 1.5 milligrams per day
• 9 to 13 years: 1.9 milligrams per day
• 14 to 18 years: 2.2 milligrams per day
• 19 years and older: 2.3 milligrams per day

Manganese deficiency is associated with infertility, bone problems, altered carbohydrate and lipid metabolism, and seizures. However, deficiency appears to be extremely rare—there's usually no need for supplemental manganese. Deficiency is most often seen in children who are on total parenteral nutrition (such as tube feeding) when those diets lacked manganese. You can get plenty of dietary manganese from both plant and animal sources to meet your needs. As such, there is more to worry about in getting overexposed to manganese rather than being deficient in it.

Manganese supplements have been marketed in ways implying a benefit for people with arthritis (often combined with glucosamine and chondroitin), osteoporosis, or diabetes. The Linus Pauling Institute says there is no solid evidence for a benefit in supplementing beyond the DRI each day or 2.0 milligrams.

Some bone health supplements have been marketed that are very high in manganese (16 to 20 times the recommended daily intake), which raises concerns of toxicity. While manganese plays a role in glucose metabolism, the Linus Pauling Institute notes that there is no evidence that manganese supplements improve glucose tolerance in people with or without diabetes.

If you're thinking about taking manganese supplements, speak to your healthcare provider first. Don't take more than the dosage recommended on the product label.

The Health and Medicine Division of National Academies of Sciences, Engineering, and Medicine says the tolerable upper limit (UL) for manganese is 11 milligrams per day for adults and about 9 milligrams per day for young teens. The UL is the highest daily amount that's thought to be safe.

Taking too much manganese may interfere with your ability to absorb iron from your diet. These two minerals share absorption and transport pathways. If you have a meal with a lot of manganese (or take manganese supplements) you will absorb less iron—and vice versa. It's possible that taking more than 11 milligrams per day could lead to cognitive problems.

The biggest sources of manganese toxicity have been from inhaled manganese dust from welding or smelting and ingested manganese from water contaminated with dry cell batteries. Cases of overexposure have also been seen in total parenteral nutrition, especially in newborns and infants.

Eating a diet that includes a variety of plant sources of food will give you plenty of manganese. This trace mineral is essential for health but you are unlikely to develop a deficiency or see a benefit due to taking more than the recommended daily intake.

Sources:

Dietary Reference Intakes Tables and Application. Health and Medicine Division of National Academies of Sciences, Engineering, and Medicine. http://www.nationalacademies.org/hmd/activities/nutrition/summarydris/dri-tables.aspx.

Higdon J, Drake VJ. Manganese. Oregon State University Linus Pauling Institute Micronutrient Information Center. http://lpi.oregonstate.edu/mic/minerals/manganese.