Oral dosage for Adults: 350 mg per day of elemental magnesium Apart from tablets, the only alternative is food sources. Selected Food Sources of Magnesium ( the number mentioned below each food item is the amount of Magnesium in my for example, Halibut, cooked 3oz contains 90mg of Magnesium) FOOD MAGNESIUM (IN MG) Halibut, cooked, 3 oz 90 Almonds, dry roasted, 1 oz 80 Cashews, dry roasted, 1 oz 75 Spinach, frozen or cooked, one half cup 75 Cereal, shredded wheat, two rectangular biscuits 55 Oatmeal, instant, fortified, prepared with water, 1 cup 55 Potato, baked with skin, one medium 50 Peanuts, dry roasted, 1 oz 50 Wheat bran, crude, 2 tablespoons 45 Yogurt, plain, skim milk, 8 fl oz 45 Bran flakes, three fourths cup 40 Rice, brown, long-grained, cooked, one half cup 40 Avocado, California, one half cup pureed 35 Kidney beans, canned, one half cup 35 Banana, raw, one medium 30 Milk, reduced fat (2%) or fat free, 1 cup 27 Bread, whole wheat, commercially prepared, one slice 25 Raisins, seedless, one fourth cup packed 25 Whole milk, 1 cup 24