ST. LOUIS — Although the feet may seem like the stepchild of the human body, you may want to pay more attention to them.

Authorities on foot health say that keeping an eye on your feet is just as important as keeping an eye on your overall health. Your feet can signal problems with undiagnosed diabetes, cardiovascular disease, kidney disease and even cancer, they say.

That means that watching your foot health can help you catch undiagnosed conditions before they do permanent damage.

"I teach my patients daily foot inspections," says Dr. Christopher Sloan, a podiatrist practicing at the Desloge Foot Care Center in Desloge, Mo. "By doing that, you know what you have, and you know what it looks like."

Sharon Plummer, a nurse practitioner with the Endocrinology Foot Clinic at the St. Louis University School of Medicine, explained that feet have the longest nerves and arteries in the body and that they're at the lowest part of the body. That makes them the body's early warning system.

Gravity is the reason, says Dr. Johnny Benjamin, director of the Joint Implant Center and Medical Specialty Procedures Surgery Center in Vero Beach, Fla. Disease can be detected because as your blood circulates to the lowest part of your body, if your heart isn't strong enough to pump it back efficiently, problems arise.

If you have diabetes, the extra sugar damages the nerves and other tissues. If your heart is weak or you have high blood pressure or other cardiovascular problems, your feet may swell. If vessels clog with impurities, tissues die and must be amputated.

"When the heart can't pump the fluid correctly, gravity pulls that fluid down into your feet," Benjamin says. "You end up thinking it's a problem with your foot or your leg when it's a problem with your heart. Kidney disease also can cause swelling."

People need to watch for changes in color and feeling, Benjamin says. "If there's a darkening or discoloration of their toes that happens fairly suddenly, that can be an indication there's a blood flow problem."

Unexplained sores and lacerations signal loss of feeling in the feet, and that signals diabetes.