Magnesium is a very important, but often over-looked, mineral for good health. Magnesium is the fourth most abundant mineral in the human body, with over 50% found in the bones. In addition to keeping bones healthy, magnesium is important for normal muscle and nerve function, keeping heart rhythm steady, and regulating blood sugar and blood pressure.
Daily Magnesium Requirements
For most adults over the age of 30, 300-400 milligrams of magnesium a day from food is the recommended dietary reference intake. According to the 1999-2000 National Health and Nutrition Examination Survey, many Americans do not get enough magnesium from their diet. Thankfully, though, actual magnesium deficiency requiring medical intervention is relatively rare because the body stores magnesium in the cells and the blood maintains a steady, regulated amount.
The best way to get magnesium, as with most nutrients, is from a well-balanced and varied diet.
The food most often listed at the top of sources of magnesium-rich foods is halibut. Just 3 ounces of this fish, or ½ of a fillet, can provide 100 milligrams of magnesium. Magnesium is one of the most abundant minerals in seawater, so other fish may also contain high amounts of the mineral, including oysters, rockfish and scallops.
For vegetarians, the best protein source of magnesium is tofu. Firm tofu contains approximately 47 milligrams in a one-half cup serving.
Fruits and Vegetables
Deep green vegetables, such as spinach, mustard or turnip greens and broccoli, are excellent sources of magnesium. The chlorophyll molecule that gives the leaves its green color contains magnesium. Because the mineral is water-soluble, the best cooking method for vegetables to maintain magnesium include steaming or microwaving with a small amount of liquid for the shortest amount of time possible. In fact, boiling spinach can result in about a one-third loss of magnesium from the food.
Other fruits and vegetables that contain magnesium include okra, avocados, potatoes, bananas, raisins and artichokes. Farming techniques and soil composition have an effect on the amount of magnesium present in the vegetables that are grown. Color loss is one of the first signs of magnesium deficiencies in plants.
Beans, Nuts and Seeds
Beans, nuts, and seeds are also a good source of magnesium. Soybeans contain the most magnesium, followed by black-eyed peas, baked beans, lentils, kidney beans and pinto beans. The nuts that contain the highest amount of the mineral per one-ounce serving size include almonds and cashews, but even an assortment of mixed nuts can provide up to 15% of the daily value. Seeds, such as pumpkin, sesame and sunflower, also provide a good dietary source of magnesium.
Refined, white flour and grains are very low in magnesium, as the mineral is present in the germ and bran portion of the grain, which is removed during processing. Whole grains, such as wheat bran, brown rice and oatmeal, are high in magnesium – another reason to switch from white bread to whole wheat.