This metal (not to be confused with another metal, manganese) is important to building bones, creating protein, conducting nerve signals to the muscles, and helping the body adapt to cold.


The best sources of magnesium are raw, green, leafy vegetables; starches; soybeans; unpolished grains; nuts (especially cashews and almonds); meat; and milk.


There is no evidence of adverse effects from consuming naturally occurring magnesium. An oversupply of magnesium from supplements, however, may cause neurological problems. It can also be dangerous to people who have reduced kidney function.


Your Daily Allowance


Diet Power sets your Personal Daily Allowance (PDA) of magnesium at the Food and Nutrition Board's Recommended Dietary Allowance (RDA), measured in milligrams. For males the PDA is 410 from age 14* to 18, 400 from age 19 to 30, and 420 after age 30. For women it's 360 from age 14* to 18, 310 from age 19 to 30, and 320 after age 30. For pregnancy it's 400 milligrams for women 18 or younger, 350 for those 19 to 30, and 360 for those 31 through 50. For lactation it's 360 for mothers 18 or younger, 310 for those 19 to 30, and 320 for those 31 through 50. (In the rare event that you are pregnant or lactating after age 50, Diet Power will assign you the 31-through-50 PDA for that reproductive state.)


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


Upper Limit


The Tolerable Upper Intake Level (UL) of magnesium refers only to the amount taken in dietary supplements, not that obtained from food. For teenagers and adults, the UL is 350 milligrams. Supplements exceeding this level may harm your health, but getting the same amount from food may be safe.


Revising Your Allowance


If your doctor recommends a different PDA, you can change it with the Personal Daily Allowance Editor.


Color Coding of This Nutrient


The magnesium bar in your personal Nutrient History is:


   image\diet0036.gif blue for "good" if you've logged 100 to 150 percent of your PDA


   image\diet0037.gif red for "bad" if you've logged less than 100 percent or more than 150 percent of your PDA.**


   image\diet0042a.gif (Unlike other nutrients, magnesium does not include a "caution" level, because of the overlap between a safe intake from food and a potentially dangerous intake from supplements. See "Upper Limit" and "Your Daily Allowance," above.)


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


In the nutrient profile of a food or recipe, the magnesium 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 magnesium


   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 magnesium


   image\diet0036.gif blue for "neutral" otherwise


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



A red bar could be misleading, however, since the UL applies only to magnesium taken in supplement form and the Nutrient History does not distinguish between supplements and foods. See "Upper Limit," above.

How Complete Are Diet Power's Magnesium Readings?


For the 8500 generic items in the Food Dictionary: fairly complete. Only 11 percent list their magnesium content as "unknown."


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


For all 11,000 items combined: not terribly complete. About 29 percent list magnesium as "unknown."


These figures mean that if you frequently log chain-restaurant foods (or user-added foods with missing magnesium readings), your Nutrient History may underreport your intake of magnesium by a few points.


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


Magnesium on Food Labels


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


The Daily Value for magnesium is 400 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.