3-D Image female skeleton with shape
Credit: Bernhard Ungerer

Few things can remind you of the years that go by like achy bones and joints can. The tide turns around age 34, when bone loss becomes faster than bone-building activities in the body. And good genes alone are no guarantee for strong bones, because diet and exercise have a lot to do with your ability to reach your peak bone mass. There are over twenty essential bone-building nutrients your body needs in order to maintain your cartilage and bony framework in good shape. Calcium and phosphorus are the most common, but they both require other minerals and vitamins for maximal efficacy.

Bone vs. Cartilage

Bone gets its hardness from its high mineral content. Mineral salts represent about 65 percent of bone tissue, while a leathery protein matrix and a small amount of water make up the remaining 35 percent. In contrast, water represents 60 to 80 percent of cartilage structure, according to the Los Angeles Valley College. The rest consists of a protein matrix and a comparatively small proportion of calcium salts in some cartilage types.  The result is a cushion-like structure that enables cartilage to absorb shock and reduce friction at your joints.


Mention bone health and most people will immediately think about the most common mineral in the human body: calcium. Calcium's structural role is so important that your body dedicates ninety-nine percent of its total content to bones and teeth. However, calcium also plays such key roles in muscle and nerve function that your body will remove it from bone if blood concentrations fall below a certain range as a result of inadequate intake. The Center for Better Bones recommends an intake of 1000 to 1300 milligrams of calcium to meet your daily needs.


Phosphorus makes up more than half of the bone mineral mass and plays an important structural role. Much of your bones' toughness comes from crystals that phosphorus forms when it combines with calcium. The result is hydroxyapatite, a compound that abounds in bones and teeth, as well as in many modern implants. When it's not bound to calcium, phosphorus circulates in the form of phosphate and helps regulate the activity of bone-building cells. Phosphates play a myriad of other roles and it takes 700 milligrams of phosphorus to fulfill the average adult's minimum daily requirements.


According to the Linus Pauling Institute, approximately 50 to 60 percent of total body magnesium occurs in bone, where magnesium links with hydroxyapatite crystals to increase their size and strength Beyond helping to give shape to your bones, magnesium regulates the metabolism of other bone minerals. It also indirectly affects the activity of bone-building cells by helping your body secrete the parathyroid hormone. Women between the ages of 19 and 30 need 310 milligrams of magnesium to meet daily requirements, but the recommended intake rises to 320 milligrams after age 31. Men's needs are higher at 400 to 420 milligrams per day.


Fluoride has such a strong chemical attraction to calcium that ninety-nine percent of your body's fluoride content finds its way to your bones and teeth, where most of the calcium is. In your teeth, fluoride cohabits with HA crystals to increase their resistance to plaque-forming bacteria, hence its common use in toothpastes. It also acts on bone-building cells to promote bone formation. At a level of 3 milligrams, a woman's adequate daily intake is slightly lower than a man's adequate intake of 4 milligrams.


You also find sodium in bone but it mostly affects bone health through its impact on calcium concentrations. The higher your sodium intake, the more calcium your kidneys will excrete in the urine. If you don't compensate for this loss by absorbing more sodium from food, your body removes calcium from bone in order to maintain normal function. Ideally, you should keep your daily sodium intake below 2300 milligrams, which is about the equivalent of a teaspoon of table salt.