Calcium is the most abundant mineral in the human body, and, for that
matter, the body of any boned animal, as it is the structural element of
bones. Whether our body is deficient in calcium depends less on whether we have a sufficient dietary intake, but rather on how well we absorb it.
An important factor in calcium absorption is Vitamin D. Vitamin D, however, doesn't have to come from food sources or supplementation; the healthy body can produce this vitamin itself for as long as it gets some exposure to sunlight every day.
During childhood and adolescence, bone deformations can happen less because the dietary intake of calcium would be lacking but rather for a lack of Vitamin D which can occur when children are kept inside for extended periods of time.
Calcium absorption also depends on hormones. Women beyond menopause are
under increased risk of developing osteoporosis (bone loss), not because
they would be lacking in dietary calcium but because they lack the estrogen needed for proper absorption.
Trace minerals such as boron also play a part in calcium absorption.
The best sources of dietary calcium are milk and milk products, as well as soy and green leafy vegetables. Recommended daily amounts for dietary calcium are about 700 milligram for a healthy adult, and about a gram for adolescents. Breast feeding women need more than one gram a day. However, they do not necessarily have to consume calcium supplements as their hormonal composition guarantees an increased calcium uptake from food.
The amounts of calcium found in many multivitamin products are a joke: 25 mg are less than 3 percent of what we need a day. Those who worry about getting enough dietary calcium should make it a habit to eat a can of sardines every day... including the soft bones. 100 grams of canned
sardines provide a minimum of 250 milligram of calcium.
But as we mentioned initially: the problem is usually not whether there is enough calcium in the food we eat, but rather whether our hormonal composition takes care of sufficient absorption.
