DEAR DR. DONOHUE: I am a 65-year-old male. I was diagnosed with a vitamin D deficiency more than two and a half years ago. I have been on 50,000 IU of vitamin D weekly ever since. In a previous article, you stated that vitamin D is fat-soluble; it is stored in body fat. Can it accumulate to a toxic level?

Can they test body fat for vitamin D toxicity? — R.R.

ANSWER: Too much vitamin D can be toxic. It causes a rise in blood calcium. High calcium levels produce fatigue and depression. They make people urinate large quantities, and such patients complain of constant thirst. Muscle weakness develops. A person’s mental function dulls.

Vitamin D is stored in fat. You don’t need to have fat analyzed for its vitamin D concentration. Blood levels of the vitamin show whether a person has too much of it on board. The blood tests you enclosed don’t show that you have toxic levels of the vitamin. They’re in the normal range. They do show, however, that you don’t need such large doses of D that you currently take.

For treating D deficiency, doses of 50,000 IU are given weekly. That dose doesn’t have to be taken for the rest of a person’s life. Once the deficiency is corrected, then the person can go back on a recommended dose of the vitamin.

The recommended daily dose of vitamin D for adults up to age 70 is 600 IU. For those 71 and older, the dose is 800 IU. The upper daily safe dose is 4,000 IU.

Maybe your doctor has information about a condition that requires the high dose you take. Ask him why you cannot go on a normal dose. You are also getting vitamin D from sunlight on your skin and from foods fortified with the vitamin — milk and cereals. Salmon, mackerel and tuna have a good amount of the vitamin.

DEAR DR. DONOHUE: My husband is 69. His mother is 95. She says he didn’t have chickenpox as a child. Should he get the shingles vaccine? No one gives us the same answer. — P.I.

ANSWER: Yes, he should get the vaccine. That’s the word from the Centers for Disease Control and Prevention. Chickenpox is highly contagious. Close to 100 percent of people older than 40 have been exposed to the chickenpox virus during childhood, and those people are carrying the chickenpox virus in their bodies. It resides in nerve cells. The virus often escapes from its nerve cell home in late life, travels down the nerve to the skin and causes a breakout of shingles.

The vaccine prevents this from happening. It does not give all people 100 percent protection. It does, however, lessen the severity of a breakout if one were to occur. It also lessens the greatest complication of shingles, postherpetic neuralgia — pain that lasts long after the shingles rash has cleared.

The booklet on shingles discusses how it arises and how it is treated and prevented. Readers can obtain a copy by writing: Dr. Donohue — No. 1201, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order for $4.75 U.S./$6 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: If you had a heart attack and the bottom of your heart is dead, what happens to that part of the heart? — B.H.

ANSWER: Heart muscle dies during a heart attack. Scar tissue replaces the dead heart muscle. It’s the same process that goes on when a piece of skin is missing.

Quite often, the heart pumps normally once the scar has filled in the dead muscle area. If a great deal of heart muscle has died, that person requires assistance to keep the heart beating strongly. The assistance is usually in the form of medicines.

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.