Manganese and magnesium are minerals your body needs to function properly, though most people don't get enough of either. The U.S. Department of Agriculture estimates that over 50 percent of Americans don't consume adequate magnesium, while approximately 37 percent lack the manganese they need daily. Dietary supplements can help you reach your recommended daily allowance, but it's best to obtain magnesium and manganese through a varied diet that includes plenty of whole grains, fruits, vegetables and lean protein.
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Function in the Body
Manganese helps regulate your blood sugar and supports the health of your nervous system. You need it to absorb calcium, break down carbohydrates and fats, and synthesize bones, endocrine hormones, connective tissue, the proteins necessary for blood coagulation and the enzyme superoxide dismutase, a powerful antioxidant. Magnesium also plays a role in bone health and energy metabolism. In addition, magnesium triggers the activity of over 300 enzymes, helps maintain the electrochemical balance your neurons and muscles need to work and aids in the production of DNA and RNA.
Effect on Your Health
If you don't consume enough manganese, you may experience seizures, muscle weakness or infertility. You may also be more likely to develop arthritis, diabetes and osteoporosis. Women who lack adequate manganese may have more severe premenstrual syndrome symptoms, such as abdominal cramps or mood swings. Being deficient in magnesium may result in trouble sleeping, heart arrhythmia, vomiting, nausea and muscle problems. A high intake of magnesium may help lower your risk of osteoporosis, heart failure, depression and high blood pressure.
Recommended Dietary Allowance
Healthy men between 19 and 30 years old need 400 milligrams of magnesium each day, while women of the same age should have 310 milligrams. Adults over 30 need slightly more: 420 milligrams daily for men and 320 milligrams for women. Your body requires much less manganese to reach your recommended daily intake. Men should have 2.3 milligrams a day, and women need about 1.8 milligrams. For magnesium, the upper tolerable limit -- the maximum amount you can consume per day without harmful side effects -- is 350 milligrams from supplements, not food; for manganese, it's 11 milligrams from food and supplements combined.
Best Food Sources
A 1-ounce serving of dry-roasted almonds contains 80 milligrams of magnesium, or 20 percent of the RDA for 19- to 30-year-old men and nearly 26 percent of the RDA for same aged women. Other excellent sources of the mineral include spinach, which supplies 78 milligrams of magnesium in every 1/2-cup cooked serving, soy milk, legumes and beans. Plant-based foods are also rich in manganese. Almonds have 0.65 milligram of manganese in every ounce, an amount that supplies 28 percent of a man's daily requirement and 36 percent of a woman's. A 1/2-cup serving of pineapple has 0.77 milligram, and pecans contain 1.3 milligrams.
- U.S. Department of Agriculture: What We Eat in America, NHANES 2001-2002: Usual Nutrient Intakes from Food Compared to Dietary Reference Intakes
- University of Maryland Medical Center: Manganese
- Office of Dietary Supplements: Magnesium
- Linus Pauling Institute: Manganese
- University of Maryland Medical Center: Magnesium