This metal (not to be confused with magnesium) is important to central-nervous-system function, bone growth, and reproduction. It also helps the body metabolize cholesterol, carbohydrates, and amino acids.


Good sources of manganese include nuts, whole grains, tea, instant coffee, cocoa powder, and some fruits and vegetablesnotably legumes.


Manganese deficiency has never been observed in human beings.


Symptoms of an oversupply include involuntary laughing, hand tremors, slurred speech, and "poker face"an immobile, deadpan expression.


Concerned about overdose, the Food and Nutrition Board (FNB). advises that "because manganese in drinking water and supplements may be more bioavailable than manganese from food, caution should be taken when using manganese supplements, especially among persons already consuming large amounts of manganese from diets high in plant products. In addition, individuals with liver disease may be distinctly subsceptible to the adverse effects of excess manganese intake."


Your Daily Allowance


Because manganese had no official Recommended Dietary Allowance (RDA), Diet Power used to set your Personal Daily Allowance (PDA) in the middle of a range called the Estimated Safe and Adequate Amount (ESAA), established by the FNB. In January 2001, however, the FNB defined a more precise figure for manganese called the Adequate Intake (AI). Diet Power now sets your PDA at this figure. For males 14* to 18 years old, it's 2.2 milligrams per day; for those 19 and older, 2.3 milligrams per day. For females 14* to 18 years old, it's 1.6 milligrams per day; for those 19 and older, 1.8 milligrams per day. The PDAs for pregnant and lactating women are 2.0 and 2.6 milligrams, respectively, for all ages through 50. (In the rare event that you're pregnant or lactating after 50, Diet Power will assign you the 50-or-younger PDA for that reproductive state.)


Upper Limit


Also in January 2001, the FNB announced a Tolerable Upper Intake Level (UL) for manganese. People 14* to 18 should get no more than 9 milligrams per day; people 19 and older, no more than 11 milligrams per day. (The same figures apply to women who are pregnant or lactating.)


* Please remember that Diet Power is not designed for people under 15.


Revising Your Allowance


Diet Power automatically sets your Personal Daily Allowance of manganese when you enroll in the program, but you can change your PDA to reflect your physician's recommendation. See Personal Daily Allowances, Editing Your.


Color Coding of This Nutrient


The manganese bar in your personal Nutrient History is:


   image\diet0036.gif blue for "good" if you've logged 100 to 140 percent of your PDA


   image\diet0037.gif red for "bad" if you've logged less than 100 percent of your PDA or more than the Tolerable Upper Intake Level (UL)


   image\diet0042.gif yellow for "caution" if you've logged more than 140 percent of your PDA


   image\diet0038.gif missing if you've logged no manganese.


In the nutrient profile of a food or recipe, the manganese bar is:


   image\diet0039.gif green for "good" if getting your entire PDA of calories from this item would give you more than 150 percent of your PDA of manganese


   image\diet0040.gif magenta for "bad" if getting all your calories from the item would give you less than 50 percent of your PDA of manganese


   image\diet0036.gif blue for "neutral" otherwise


   image\diet0038.gif missing if the amount of manganese is either zero or (when the word Manganese is grayed out) unknown.


How Complete Are Diet Power's Manganese Readings?


For the 8500 generic items in the Food Dictionary: not terribly complete. About 28 percent list their manganese content as "unknown."


For the 2500 chain-restaurant items: totally incomplete. All list manganese as "unknown."


For all 11,000 items combined: not terribly complete. About 43 percent list manganese as "unknown."


These figures mean that your Nutrient History will almost always underreport your intake of manganese, unless you log mostly foods with manganese readings that you've added to the dictionary yourself.


To see whether a particular food has a manganese reading, open the Food Dictionary and check the food's nutrient profile. If you find a question mark beside "Manganese," it means the amount is unknown. (To see all foods with unknown manganese readings, click the dictionary's PowerFoods tab and sort the foods by manganese power; then scroll toward the bottom of the list until you see foods with question marks in the "Power Rating" column.)


Manganese on Food Labels


Food labels are not required to report manganese content, but some do voluntarily. They may cite the content in milligrams, percent of Daily Value, or both.


The Daily Value for manganese is 2.0 milligrams. This isn't necessarily right for you, howeverit's a rough estimate meant to cover most of the U.S. population.


For more on label regulations, see Labels, Food.