Nutrition & bone health
Key minerals for bone health — calcium
by Dr. Susan E. Brown, PhD
Of all the minerals in the body, there is more calcium than any other. It makes
up somewhere around 2% of our total adult body weight, stored mostly in our bones
and teeth. Bone is made up of a crystalline mineral compound embedded within a living
protein matrix. This crystalline mineral compound, called hydroxyapatite, is formed
principally from calcium and phosphorus. It is essential for healthy bone development
and bone maintenance, and gives our bones both strength and rigidity.
Here in the United States, about 80% of our calcium comes from dairy sources. But
research indicates that dietary calcium from sources such as vegetables, fruits,
or the small bones of fish such as canned salmon or anchovies, may be much more
readily absorbed than calcium from dairy foods. While most Americans think they
need to drink milk to get enough calcium, bok choy, a variety of Chinese cabbage,
is one of the best calcium bargains around as far as absorbability per unit of energy
— providing around 1800 mg calcium per 100 calories! Another good source is
bones themselves: since the invention of fire, people have been boiling up bones
for the rich nutrients they contain. (Homemade broth is not only curative for the
common cold, it’s prophylactic for bone health!)
As for calcium supplements, it’s true that not all are created equally. We
hear a lot about the different forms of supplemental calcium and which ones are
best. But the biggest story with calcium is not so much about which form to use
as it is about calcium absorption — which itself is contingent on a complex
interplay of hormones and other factors, chief of which is related to vitamin D.
While it’s interesting that calcium comes in all these various forms, without
adequate vitamin D on board (vitamin D sufficiency is commonly defined as a 25(OH)D
blood level of at least 32–34 ng/mL), all the calcium in the world will result in
little material gain for our bones. In fact, noted calcium researcher Dr. Robert
Heaney has found that different individuals can have a nearly threefold difference
in their calcium absorption rates — a phenomenon for which we currently have
only limited explanation. Aside from how replete our vitamin D stores are, how well
we absorb calcium has much to do with the health of our digestive system.
As to which forms optimize both absorption and bioavailability, alkalizing calcium
salts are the best calcium compounds known to date. These forms include calcium
citrate, calcium citrate–malate, calcium ascorbate, and calcium carbonate. Calcium
citrate and its relative, calcium citrate–malate (CCM), are sources that do not
require hydrochloric acid (HCl) from the stomach for absorption, so the calcium
in them is very bioavailable to the body and a good choice for people with low stomach
acid. Calcium in the form of calcium citrate also appears to play a protective role
against the formation of kidney stones, and does not appear to interfere with iron
absorption from food. Calcium carbonate is often found not to be as well absorbed
as citrate, but does alkalize well in the body if taken with food. (Calcium absorption
from all forms is generally better when taken with a meal.)
Regardless of what form your calcium supplementation takes, it should always be
balanced with magnesium supplementation. Some bone specialists favor magnesium-centered
formulations with equal or slightly more magnesium than calcium. As a rule of thumb,
I recommend at least half as much magnesium as calcium (a ratio of 1 part magnesium
to 2 parts calcium), and in most cases I prefer nearly as much magnesium as calcium.
People with osteoarthritis, in particular, want to use equal amounts of magnesium
and calcium.
Many US experts now suggest that the ideal daily calcium intake from all sources,
including food and supplements, would be in the range of 1000–1200 mg. (For more
on how bone serves as a calcium reserve for everyday body processes, see our article
on the natural approach to bone health.)
See also our list of calcium-rich foods for the best dietary sources of this important
bone-building mineral.
Return to table
Our Personal Program is a great place to start
At the Center for Better Bones we promote an all-natural approach to bone regeneration
and repair that includes nutrition, diet, exercise, and lifestyle guidance. Our
Personal Program is a convenient, at-home version of this approach.
- To assess your fracture risk and the health of your bones, take our free, on-line
Fracture Risk and Bone Health Profile.
- To learn more about the guided, at-home Program we have developed with America’s
premier women’s health clinic, Women to Women, go to
The Personal Program for Better Bones.
- For more information about the at-home program for Better Bones, please call The
Personal Program toll-free at 1-877-200-1269.
Original Publication Date: 04/11/2000
Last Modified:
04/14/2010
Principal Author: Dr. Susan E. Brown, PhD