DEAR DR. DONOHUE: There is confusion in the medical field about sodium, an element, and sodium chloride, a compound. Because of this confusion, all sodium compounds are assumed to raise blood pressure. You will make me happy by commenting on the sodium-versus-sodium-chloride point. – A.G.

ANSWER: I apologize for having to edit your letter so severely. I have omitted many points you made.

Sodium – either as sodium chloride or any other sodium compound – is believed to be the blood-pressure-raising ingredient in salt. So the emphasis is on sodium in any combination. For most people, sodium chloride – table salt – is the major source of sodium. If a person uses large amounts of other sodium compounds (combinations), those compounds must also be restricted.

Confusion arises when the sodium content of foods is listed as sodium or sodium chloride. If the label specifies sodium chloride, the amount of sodium is only 40 percent of that weight.

A low-sodium diet is one where the sodium chloride allowance is 6,000 mg. The same diet, expressed as milligrams of sodium, is 2,400 mg (6,000 x 0.4). One teaspoon of salt has 6,000 mg of sodium chloride or, stated with the focus on sodium alone, 2,400 mg of sodium. Most of us eat three times that amount every day.

It really is not salt from the salt shaker that creates the problem. We get most of our salt from processed foods, such as commercial soups, canned foods, frozen dinners and processed meats, all of which are very high in salt. Potato chips, salted nuts and pretzels are other highly salted foods. So too are sauerkraut and pickles.

DEAR DR. DONOHUE: I am a 14-year-old girl. I am 5 feet tall and weigh 100 pounds. Do you have any tips on how to grow taller or any information on height? – K.S.

ANSWER: Your height and weight put you toward the bottom of the scale for a girl your age. But this is not the time to panic. Your short stature might be nothing more than a family trait, or it might be that you are a late bloomer, destined to grow in the near future.

Peak growth for girls usually occurs between ages 10 and 12, when they add 3.3 to 4.1 inches (8.5 to 10.5 cm) to their height.

Why you have not had this growth spurt I cannot answer. It would be a wise move to have your mother take you to the family doctor, who can order a few tests that help predict what your eventual height will be and whether there is a physical problem causing growth delay.

Bone X-rays reveal your bone age. If your bone age is less than that of other 14-year-olds, then you are likely to have a late growth surge, and not much more need be done other than wait.

Checking hormones is a way to see if your delay in height comes from a lagging hormone production. If that is the case, then hormones can be prescribed and you will become taller.

There is a rule whose accuracy is quite poor, but it is often evoked to predict children’s adult height. Subtract 5 inches from your dad’s height in inches. Then add that number to your mother’s height in inches. Divide that number by 2, and that gives you an estimate of what your adult height should be, as programmed by your genes.

The rule for boys goes like this: Add 5 inches to the mother’s height, and add that number to the father’s height. All measurements are in inches. Divide the sum of those heights by 2 to arrive at a predicted adult height.

Don’t put a whole lot of stock in this rule.

DEAR DR. DONOHUE: Would you please tell me the difference between “enriched” and “fortified” when those terms appear on food labels? I take them to mean the same thing. Am I wrong? – K.P.

ANSWER: They do not mean the same thing.

“Enriched” means that the nutrients (vitamins and minerals) that were lost in processing the food are returned to the food before it is packaged or canned.

“Fortified” is the addition of a nutrient (vitamin or mineral) to foods that they did not contain in their natural state.

DEAR DR. DONOHUE: I have a terrible cough and can’t get rid of it. I took medicines for allergies, but they did no good. Do you recommend anything else? – M.F.

ANSWER: In the strongest words I can offer, I recommend a doctor exam.

Coughs are protective reflexes. They clear germs and mucus out of airways. A cough that lasts and lasts indicates something rotten is going on. The cause must be found.

The list of cough causes is long. I cannot tiptoe around the most dreaded cause – cancer. It’s not the most common cause, but it’s the one that demands immediate investigation.

People with chronic bronchitis are almost always current or former smokers. If you have never smoked, then that makes chronic bronchitis less likely.

Asthma does not lag far behind chronic bronchitis on the list. Asthma can come at any age. During the night, the upward splashing of stomach acid and stomach juices can precipitate asthmatic coughing. The upward splashing of stomach juices is what people call heartburn and doctors call GERD – gastroesophageal reflux disease.

Postnasal drip – the relentless trickle of thick mucus from the nose and sinuses into the throat – often provokes attacks of coughing, especially during the night.

Medicines are frequently indicated. ACE inhibitors – Altace, Capoten, Lotensin, Zestril, Accupril and Vasotec – are examples. They are blood-pressure-lowering medicines and are also used to treat heart failure.

Finding the cause often entails resorting to special tests. The chest X-ray, valuable as it is, does not identify all cough causes. Lung scans add more information. A direct look into the airways with a scope called a bronchoscope provides invaluable data. Stop self-medicating. You need up-close and personal advice.

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.