Magnesium is a trace mineral that is found in many plant and animal products, including nuts and seeds, leafy green vegetables, beans, salmon, milk and chicken breasts. Pumpkin seeds are notably high in magnesium, containing 190 mg per 1/4-cup serving, and cashews contain 116 mg of magnesium per 1/4 cup. When it comes to leafy greens, spinach contains 156 mg per cup, and Swiss chard contains 150 mg per cup.
Animal products are not typically as high in magnesium as the magnesium-rich plant foods, but several are considered "good" sources. Salmon, for example, contains 26 mg of magnesium per 3-ounce serving, and milk contains 24 to 27 mg per cup. Chicken breast meat contains 22 mg of magnesium per 3-ounce serving.
The Recommended Dietary Allowance for magnesium is 400 mg per day for males ages 19 to 30, and 310 mg of females ages 19 to 30. For males ages 31 and older, the RDA is 420 mg, and for females ages 31 and older, the RDA is 320 mg. Children's magnesium needs are lower than those of adults, except during the teen years, when rapid growth causes the RDA to rise to 410 mg for males and 360 mg for females.
Magnesium is involved in a number of metabolic pathways in the body. It helps build strong bone and muscle, and it also helps regulate blood pressure. Recent studies have found that increasing magnesium intake reduces the risk of high blood pressure and heart attack. Magnesium also plays a role in muscle contraction, and a deficiency of this mineral can lead to cramps and muscle aches.