One cup of cooked spinach contains about 240–245 milligrams of calcium, but oxalates limit absorption to roughly 5%.

Fortified soy milk contains 200 to 400 mg of calcium per cup, while unfortified soy milk has only about 10 to 30 mg — checking the label is the only.

An 8-ounce cup of skim milk contains about 300 mg of calcium, slightly more than whole milk due to the absence of fat.

A single tablespoon of dried whole sesame seeds contains about 88 mg of calcium, though the amount varies by variety and preparation method.

A 3-ounce serving of canned sardines with bones provides about 325 mg of calcium, roughly 33% of the daily adult requirement.

A 3-ounce serving of canned salmon with bones provides about 180 mg of calcium, while the same amount of fresh, boneless salmon has only about 36 mg.

One cup of shredded romaine lettuce contains about 20 milligrams of calcium, though the amount varies by growing conditions and variety.

Rice contains very little calcium — a cup of cooked white rice has roughly 2 to 6 milligrams, and brown rice has about 19.5 milligrams.

Most prenatal vitamins contain 200 to 300 mg of calcium per serving, typically falling short of the 1,000 mg daily need during pregnancy.

A medium russet potato with skin contains roughly 22 mg of calcium, which is only about 2% of the daily recommended value.