DEAR DR. DONOHUE: My son is 54 and just found out he has hemochromatosis. We have never heard of it. He is very athletic and health-conscious. No one in our family has had this. How did he get it? Is it treatable and curable? – L.H.

ANSWER: In spite of its unusual name, hemochromatosis (HE-moe-CROW-muh-TOE-suss) is not an unusual illness. It’s a common, inherited illness.

It is treatable. It doesn’t go away, but with continued treatment it doesn’t damage the person or the person’s body. We have an inborn control in our digestive tract that allows just the right amount of iron to get into the blood.

People with hemochromatosis have a control that’s not working well. Too much iron gets into their blood. In time, the excess iron infiltrates the liver, pancreas, skin, joints, heart and pituitary gland.

If the diagnosis is made before there is organ damage, then all is well. Liver involvement is a major problem. If iron isn’t removed, excessive iron kills liver cells. The liver becomes cirrhotic – filled with scar tissue – and stops functioning.

With an iron-filled pancreas, diabetes results. In the heart, iron deposits bring on heart failure. You and your husband are probably carriers of the hemochromatosis gene.

It takes two genes to produce the illness. People with one gene are rarely affected by it. Your son inherited a gene from both your husband and you. Your other children, if you have any, must have gotten only one gene.

Nevertheless, they and their children should be checked for the illness. Most certainly, your son’s children should be screened for it. Treatment is simple. It consists of removing blood.

Blood is the body’s chief iron reservoir. Once body iron reaches an acceptable level, blood removal is done less frequently, but it is something that has to be continued for life.

DEAR DR. DONOHUE: Every night I have nightmares. Why? – J.V.

ANSWER: Nightmares are frightening dreams that can usually be recalled the next day. They occur during REM (rapid eye movement) sleep, the sleep phase during which most dreaming happens.

Stress, past traumatic experiences, medicines, stimulation by a TV program or book and stopping heavy alcohol or sedative use can all give rise to nightmares.

Then, too, there is the inexplicable cause. If the nightmares are bothering you or if you have other symptoms typical of mental unrest, you should consult a mental-health professional.

DEAR DR. DONOHUE: I walk a lot, three to four times a day for 10 minutes. My metabolism isn’t very high. How can I raise it? I can’t lose weight if I don’t. – D.K.

ANSWER: By metabolism, you mean your ability to burn calories. Some people are born with a low metabolism, and everything they eat stays with them as body fat.

Others can eat all day long and not gain a single ounce. They have a high body metabolism. There isn’t a whole lot a person can do about changing his or her genetic makeup.

You can, however, increase your body’s metabolism if you increase your muscularity.

Muscle is active tissue. It burns calories even when it’s not active. Fat, however, just sits there unless the body needs extra fuel to support its activity.

If you increase the time you spend walking and if you pick up the pace of your walks, you will find that your metabolism will speed up.

DEAR DR. DONOHUE: With all respect, my one objection to your writing is your frequent and consistent use of the word “germ.” It was used in the 16th century by people who did not understand microbes – bacteria and viruses. – M.W.

ANSWER: I understand how a Ph.D. microbiologist is offended by the word “germ.” I tell you what, professor.

If readers agree with you, I’ll retire “germ” to the dustbin of history.

DEAR DR. DONOHUE: I am concerned about the last paragraph of your article on omega-3 fats, where you said people with implanted defibrillators are not encouraged to increase their intake of them. Why not? My cardiologist doesn’t know why. – L.P.

ANSWER: You aren’t the only one troubled by that statement. Let me back up for readers. Omega-3 fats and oils are believed to prevent heart attacks.

These fats are found in fish, and people are told to eat two fish meals a week – salmon, herring, mackerel, tuna or sardines.

Reports suggest that people with an implanted defibrillator possibly get more defibrillator shocks when they consume omega-3s.

These people don’t have to stop using omega-3s, but they might be better off not going hog wild with them. The effect of omega-3s on these people is currently under study.

So long as a person’s doctor has sanctioned their use, use them.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com