Calcium is an essential mineral and it’s one of the most commonly under-consumed nutrients. While everyone seems to know that calcium is needed to establish and maintain strong bones, its other vital roles in the body are often overlooked.

So here’s the run down on our dear friend calcium, what it does for you, and how you can insure you’re getting enough of it.

The calcium in an average adult body weighs about 2.5 pounds. Although 99% of this calcium is found in bones and teeth, the remaining 1%, which circulates through the rest of the cells, is critical.

That small 1% is essential for blood clotting, transmitting nerve impulses, and contracting muscles. These functions are so crucial that if your calcium intake is not adequate, your body will do all that it can to maintain blood calcium levels, at the expense of your bones. This essentially means that your body will borrow what calcium it needs from your bones in order to insure all your other cells have enough. Over time, habitual low calcium consumption takes its toll, your bones slowly become depleted as their calcium is continually removed to keep blood levels constant, and eventually fragile, brittle bones and osteoporosis result.

Since your bones would really appreciate you not racking up a calcium debt with them, here’s what you can eat to increase your calcium intake.

Good source of calcium include:

Dairy products (except for cottage cheese)

Leafy greens (such as kale, collard, turnip and mustard greens)

Canned salmon and sardines (the bones contain calcium)

Calcium fortified orange juice

Calcium supplements

Although it is very important to make sure you are eating enough calcium containing foods or supplementing your diet, your calcium absorption, unfortunately, depends on more than just how much calcium you consume.

Our bodies only absorb roughly 20-40% of the calcium we intake. This amount varies from person to person and is affected by factors such as age. Postmenopausal women typically absorb less.

Your calcium absorption will decrease if:

You have a vitamin D deficiency. Vitamin D is required for calcium absorption.

You drink excessive amounts of soft drinks. Most soft drinks contain high levels of phosphorus. Phosphorus reduces calcium absorption.

Your body produces inadequate amounts of stomach acid. Calcium requires a slightly acidic pH to be absorbed by your body; low stomach acid production can decrease its availability.

You consume large amounts of fiber in your diet, especially wheat bran. Fiber binds to calcium and prevents it from being absorbed.

If you aren’t regularly eating foods high in calcium I recommend supplementation. Here are some guidelines to follow with calcium supplements:

Don’t take more than 500 mg of calcium at once; your body won’t absorb any more than that at a given time. Supplementing your calcium intake with 1000 mg of calcium, taken in two (500 mg) doses daily, is safe and typically adequate.

Not all calcium supplements are created equal. If a supplement doesn’t dissolve in your gastrointestinal tract, it can’t be absorbed. To test how well a calcium supplement will dissolve place a tablet in 6 oz of cider vinegar for 30 minutes, stirring every 5 minutes. If it hasn’t dissolved within the 30 minutes, it’s no good.

As long as your stomach produces normal amounts of gastric acid it’s best to take your calcium supplement between meals. Calcium competes with iron for absorption, so this will limit the negative impact supplementation has on iron absorption. If you have low gastric acid production, take your calcium supplement with meals, when stomach acid levels are at their highest, or take calcium in the form of calcium citrate. Calcium citrate is an acidic form of calcium, so it doesn’t require as much stomach acid to be absorbed.

It is important to remember that although your body absolutely needs calcium, you can get too much of a good thing. I don’t recommend supplementing with more than 1000 mg of calcium/day. Calcium intakes above 2000 mg/day can cause kidney stones, kidney failure, and soft tissue calcification, so don’t overdo it.

Make your bones smile-eat some calcium!