Phosphorus

Daily Value: 1,000 milligrams

Good Food Sources: Halibut, nonfat yogurt, salmon, skim milk, chicken breast, oatmeal, extra-lean ground beef, broccoli, lima beans

What do a Bengal tiger and a teenager have in common? Depending on their chow, they may both be getting too much phosphorus.

Years ago, after noticing that the big cats in some zoos simply lay in their cages all day, researchers found that the animals' feed was high in phosphorus and dangerously low in calcium. To be sure, a calcium-phosphorus imbalance has yet to be linked to teenage couch-potato syndrome. But some experts believe teens who drink too much soda may have a phosphorus imbalance that could lead to osteoporosis later in life.

The mineral phosphorus is needed for many of the chemical reactions in the body. Phosphorus compounds help regulate the release of energy that fuels our bodies. By combining with calcium, phosphorus also helps form hard, crystal-like substances that create the latticework undergirding strong bones and teeth. In fact, 85 percent of the body's phosphorus is located in bone.

That may be part of the problem. The mechanism regulating the body's balance of calcium and phosphorus is so finely calibrated that getting too much phosphorus actually causes calcium to be removed from your skeleton and sent to your blood. Long-term calcium loss has been found to cause osteoporosis, a weakening of the bones that can lead to tooth loss and fractures.

Eating natural forms of phosphorus, which is found in everything from chicken and broccoli to milk and fruits, isn't likely to give you too much of this mineral. But some experts are worried that drinking too much soda--such as cola, root beer, and even clear drinks--can tip your delicate calcium-phosphorus balance in the wrong direction. Moreover, by forsaking milk for soda, you're further reducing your calcium intake, says John Anderson, Ph.D., professor of nutrition in the Schools of Public Health and Medicine at the University of North Carolina at Chapel Hill.

"That's where you get hurt the worst. You are compounding the problem. You are getting low calcium and high phosphorus," says Dr. Anderson.

It seems soda and many processed foods contain either phosphoric acid or some form of phosphate, both of which are hefty sources of phosphorus.

"Phosphoric acid is used in cola soft drinks to give them an acid taste," says Dr. Anderson. "Added to foods, phosphates may act as preservatives or perhaps even help alter the physical quality."

In rare cases, people who use antacids containing aluminum hydroxide for long periods of time might suffer from weakness, loss of appetite, malaise and bone loss. This chemical apparently prevents phosphorus from being absorbed.

Using Phosphorus Safely

Experts say there's virtually no reason to ever take a phosphorus supplement. It's easy to get enough phosphorus from your diet.