Usually, doctors will perform more tests, prompting the patient's body to yield a hint as to what's wrong—some clue as to why a most carefully maintained balance of natural chemicals has gone askew.
Like Confused, many of us have an encounter with biochemistry without even knowing it.
In health and in disease, our bodies are biochemical laboratories abuzz with activity, where molecules are constantly being made, used, broken down, and recycled. What does the lion's share of the work? Indispensable molecules called enzymes.
When routine blood tests reveal abnormally high liver enzyme levels, for instance, there are many potential causes, depending on which enzyme levels are awry and how off-kilter the levels are. The culprit could be as serious as alcoholism or infection with one of the hepatitis viruses, both of which can cripple the liver over time. Or the cause could be as innocuous as taking certain common medicines or having a few extra drinks at a party.
Many of the body's enzymes reside inside cells. If cells are damaged, they break apart and spill their contents into neighboring body fluids, like blood. The presence of higher-than-normal levels of enzymes in the blood can signify trouble in the tissues or organs (such as the liver) that those cells normally populate. But sometimes, abnormal lab results mean nothing at all. Elevated enzyme levels caused by the body's processing of "toxins"—including substances like chemicals in the environment, prescribed medicines, or alcohol—usually return to normal once the foreign substance is gone from the scene.
The liver is not the only place enzymes hang out. Every cell in every organ—from the liver to the heart to the skin—is chock full of enzymes. Anything but innocent bystanders, enzymes are the reason why cells are bustling centers of activity.
Enzymes underlie our ability to move, to think, to sense our world. Enzymes help us wink an eye, savor an ice cream cone, and catch a sticky drip about to fall off the edge of the cone. Enzymes, and their essential cellular associates—other proteins, nucleotides, sugars, and fats—allow a stubbed toe to heal properly and nurture a fetus growing inside a woman's body.
But when they are not working properly, enzymes can cause disease. Cancer can happen when the enzymes that copy the genetic material DNA make mistakes, giving rise to an errant gene that produces a faulty protein, or no protein at all. If that particular protein is the one that keeps a given set of cells from multiplying out of control, then its absence can bring about dire consequences.
Although a scientist may study a couple of isolated enzymes in the laboratory, inside the body enzymes are never lonely. They link up to form vibrant networks and pathways. The study of biochemical pathways and networks, and how they reverberate and influence each other, is the science of life and the chemistry of health.