Calcium

Calcium is essential for building strong bones and teeth and it is also important for maintaining a normal heartbeat and regulating blood pressure.
In addition to above benefits as per some studies calcium supplements may help relieve premenstrual syndrome
(PMS).

Calcium - How much is needed?
Average adult men and women (including pregnant women) need at least 1000mg of calcium daily, while post-menopausal women need up to 1,200mg a day

Following food would give you some idea about how much calcium they have.
Dairy:

Milk (1 cup): 300 mg
Yogurt (175 mL): 300 mg

Soy:

Calcium-fortified soy drink (1 cup): 300 mg
Tofu (1/2 cup): 250 mg

Canned Fish:

Canned salmon with bones (3 oz): 200 mg
Canned sardines with bones (3 oz): 250 mg

Calcium is also found in dark green vegetables and dried beans. Or, you can use calcium-fortified products such as orange juice, cereal bars.