Calcium is a nutrient necessary for the growth and maintenance of strong teeth and bones, nerve signaling, muscle contraction, and secretion of certain hormones and enzymes. (1)
While rare, a deficiency in calcium can lead to numbness in fingers and toes, muscle cramps, convulsions, lethargy, loss of appetite, and abnormal heart rhythms. A long term deficiency can lead to bone loss (osteopenia) and fragile bones (osteoporosis). (1)
Conversely, excess calcium (particularly from supplements) can lead to kidney stones, calcification of soft tissue, and increased risk of vascular diseases like stroke and heart attack. (1)
High calcium foods include tofu, milk, yogurt, cheese, leafy greens, beans, clams, okra, trout, and acorn squash. (2) The daily value (DV) for calcium is 1300mg. (1,3)
While there is some evidence that phytic acid and oxalic acid in beans and greens can hinder calcium absorption, green vegetables and beans are still a good source of calcium, and the calculated daily value (DV) already takes into account absorption and bio-availability. (4,5,6) For more info, see the section on calcium absorption.
Below is a list of high calcium foods by a common serving size, for more see the nutrient ranking of over 200 foods high in calcium. Also see the lists of high calcium vegetables, and high calcium fruits.