I f you want to keep your bones healthy as you age, it’s important to be sure that you are getting vitamin D and calcium in adequate amounts -- both, not one or the other.

Each has important health benefits on its own, while together these two are like "team health" for older adults. Since the US Department of Agriculture has just published new research highlighting how important it is to get sufficient calcium and vitamin D, I decided to revisit these two vital nutrients with nutrition expert Andrew L. Rubman, ND.

More than 25 million adults (men and women) in the US either already have or are at risk for osteoporosis. It’s common to equate osteoporosis with inadequate calcium, but according to Dr. Rubman, inadequate vitamin D is a far more pervasive threat. Here’s why: When calcium levels fall, the body activates vitamin D. It gets sent to the gut to encourage better calcium absorption and to the kidneys to limit calcium loss in urine. Without enough of it, bones grow thin and brittle.

This is why getting calcium alone isn’t the answer to bone health -- you must also get enough vitamin D. You can get it from foods (salmon, tuna, mackerel, fish liver oils, D-fortified foods such as milk, orange juice and breakfast cereals), and your body can synthesize it from 10 to 15 minutes of daily sun exposure. But the body’s ability to manufacture vitamin D diminishes with age, and most Americans are short on it, so Dr. Rubman prescribes up to 2,000 IU daily of vitamin D3 (cholecalciferol) to many patients. Note: The current government-recommended intake is only 400 IU daily for adults age 51 to 70 -- but experts agree that this is too low, and there are plans to raise it. In the meantime, Dr. Rubman suggests asking your doctor to test your D3 level to see if you are deficient -- especially important for seniors, he notes, as well as all people who may not be spending much time in the sun.

To get enough calcium: The official recommended calcium intake for American adults age 50 and older is 1,200 mg daily, and this is generally sufficient if your body is absorbing it properly. However, insufficient stomach acid due to aging or stress or, worse, the persistent use of acid-blocking medications, can impede this process. A supplement is one option, but perhaps not necessary -- most people can get sufficient calcium from dietary sources. Cow’s milk, even though it contains 300 mg of calcium per cup, is not necessarily the best choice since it is tough for many people to digest fully. Here are some good dietary sources: One cup of goat’s milk contains 325 mg of calcium... a cup of collard greens 350 mg... three ounces of canned salmon 180 mg... and a cup of boiled black-eyed peas 210 mg. That’s practically a day’s worth of calcium right there!

Getting sufficient amounts of these vital nutrients isn’t hard -- and it is vitally important. Remember -- when it comes to bone health, calcium and vitamin D need each other to deliver the benefit.