DEAR DR. DONOHUE: I have heard a low-salt diet recommended for such conditions as high blood pressure and swelling. What are the effects of a low-salt diet? Is it possible to have too little salt in the diet? – B.A.

ANSWER: For the sake of simplicity, in this answer salt, sodium and sodium chloride are the same thing.

The body holds onto sodium so effectively that only small amounts are needed in anyone’s diet. Everyone gets far too much without trying. It takes about 500 mg of sodium a day to keep things running smoothly. The average North American gets eight times that amount.

Current recommendations for daily sodium intake call for 1,500 to 2,300 mg. No one is going to get into any trouble from following a low-salt diet.

This doesn’t mean that people’s blood sodium levels cannot drop and lead to serious problems. They don’t drop from not eating enough sodium. They drop for other reasons. Low blood sodium can cause nausea, headache, confusion and even stupor.

The booklet on sodium, potassium and other minerals explains these confusing topics clearly. Readers can obtain a copy by writing: Dr. Donohue – No. 202, Box 536475, Orlando, FL 38253-6475. Enclose a check or money order (no cash) for $4.75 U.S./$6.75 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

DEAR DR. DONOHUE: My problem is the complete opposite of most people’s. I have a cholesterol count of 87 (2.25). I would like to bring it up without eating in an unhealthy way. Can this be done? I am trying to lose five to 10 pounds. – D.K.

ANSWER: Is 87 mg/dL (2.25 mmol/L) your total cholesterol count? Not the LDL cholesterol or HDL cholesterol number? If it is, that’s the lowest total cholesterol reading I have seen. The normal total cholesterol should be 200 (5.7) or lower, but not many people have a count in you range.

What’s the significance of such a low cholesterol number? If there are no other signs of ill health, then such a count is probably not a dangerous sign.

Low cholesterol can indicate that the digestive tract is not absorbing food. But you are trying to lose some weight, so a malabsorption condition is unlikely. Almost all malabsorption illnesses put a person on the skinny side. Furthermore, malabsorption syndromes don’t usually single out a particular substance like cholesterol. People with such a problem develop vitamin and mineral deficiencies, and often diarrhea is a symptom.

An overactive thyroid gland can lower blood cholesterol. That’s something worth looking into.

Low cholesterol has been cited as a bad sign for people with heart failure. That’s only a possibility and not accepted by all authorities on the subject.

Pernicious anemia and some liver diseases can bring down the cholesterol number.

I take it that your doctor is aware of the value. If not, he or she needs to be. I also take it that your doctor has examined you in the recent past and found nothing wrong. If that’s not true, then be examined.

If your doctor has pronounced you to be in good health, there is no reason for you to try to raise your cholesterol. You’re doing fine at the level it’s at.

DEAR DR. DONOHUE: I am writing about my daughter-in-law, 21 years old. She has been married for two years and has a 1- and a 2-year-old. She has trichotillomania. When I first met her, she was wearing a full wig. Her hair grew back, and she was able to get rid of the wig.

Now she has her head plucked just about bald again. What are we to do? – Anon.

ANSWER: Trichotillomania (TRICK-oh-TILL-oh-MAIN-ee-uh) is an irresistible impulse to put out hair. Before pulling out the hair, the person is overcome with anxiety. Pulling out the hair relieves the anxiety – temporarily.

You wrote a very long letter indicating that this young woman has more serious problems than hair-pulling, as serious as that is. She must see a mental-health professional to get the help she so desperately needs in so many aspects of her life.

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.