Organic magnesium is important in both plant and animal life. Chlorophylls are
magnesium-centered porphyrins. The adult daily nutritional requirement, which is
affected by various factors including gender, weight and size, is 300-400 mg/day.
Many enzymes require the presence of magnesium ions for their catalytic action.
Inadequate magnesium intake frequently causes muscle spasms, and has been associated
with cardiovascular disease, diabetes, high blood
pressure and osteoporosis.
Green vegetables such as spinach provide magnesium because the center of the
chlorophyll molecule contains magnesium. Nuts, seeds, and some whole grains are also
good sources of magnesium.
Although magnesium is present in many foods, it usually occurs in small amounts. As
with most nutrients, daily needs for magnesium cannot be met from a single food.
Eating a wide variety of foods, including five servings of fruits and vegetables
daily and plenty of whole grains, helps to ensure an adequate intake of
magnesium.
The magnesium content of refined foods is usually low. Whole-wheat bread, for
example, has twice as much magnesium as white bread because the magnesium-rich germ
and bran are removed when white flour is processed. The table of food sources of
magnesium suggests many dietary sources of magnesium.
Water can provide magnesium, but the amount varies according to the water supply.
"Hard" water contains more magnesium than "soft" water. Dietary surveys do not
estimate magnesium intake from water, which may lead to underestimating total
magnesium intake and its variability.
Following are some foods and the amount of magnesium in them:
spinach (1/2 cup) = 80 milligrams (mg)
peanut butter (2 tablespoons) = 50 mg
black-eyed peas (1/2 cup) = 45 mg
milk, low fat (1 cup) = 40 mg
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