Calcium is the major mineral in bone but it is also a key “electrolyte” involved in all muscular contractions and nerve transmissions. Calcium is so important in the body that its level in the blood remains stable even if no calcium is consumed because our bones supply what we don’t eat. We excrete calcium each and everyday in our feces and urine, and Vitamin D plays a huge role in how much calcium we use and absorb. This is why cows milk is fortified with Vitamin D. The human diet has very few natural sources of vitamin D (cod liver oil, small amounts in sunlight exposed mushrooms, fortified foods). If your diet is low in calcium or vitamin D, your ability to maintain bone health (as well as many other aspects of health) will be challenged. Calcium should be eaten or taken as a supplement at least 2x per day (1,000 mg per day for most of us) and vitamin D needs to be taken regularly in a supplement (1,000-2,000 IU/day), especially if you avoid fortified milk or the sun
