Sea salt and table salt both contain sodium chloride. Sea salt also contains small amounts of magnesium chloride, magnesium sulfate and calcium sulfate, which are nutritionally insignificant. Sea salt, kosher salt, monosodium glutamate, and seasoning salts are all treated the same way in your body.

You need to eat foods that contain iodine for your body to be able to make thyroid hormone. The best sources are iodized salt and seafood. Plants can be a good source, but only if they are grown on iodine-rich soil. A study in the Annals of Nutrition and Metabolism (September-October 2003) showed that vegetarians are at increased risk for iodine deficiency that causes low thyroid function. In this study, 25 percent of vegetarians and 80 percent of vegans had low blood levels of iodine, compared to only nine percent of people who eat both meat and vegetables. While iodized table salt is a good source of iodine, sea salt often is not. If you don't use table salt or eat ocean fish or kelp, get a blood test for iodine. If your iodine level is low, you need to eat more seafood or iodized salt, or take iodine pills.

Many people go on low salt diets because they think that it will improve their health, but a low-salt diet usually does not lower high blood pressure. The most healthy diet contains lots of whole grains, vegetables, seeds and nuts, and they all taste better with salt. You cannot exercise in the heat without taking extra salt.

If you want to reduce the amount of salt in your diet and fool your taste buds, try adding tart flavoring such as lemon juice or vinegar.

Gabe Mirkin, M.D.

Dr. Gabe Mirkin has been a radio talk show host for 25 years and practicing physician for more than 40 years; he is board certified in Sports Medicine and three other specialties.

Dr. Mirkin's daily features on fitness have been heard on CBS Radio News stations since the 1970's. He has written 16 books including The Sportsmedicine Book, the best-selling book on the subject that has been translated into many languages. His latest book is The Healthy Heart Miracle, published by HarperCollins.

Dr. Mirkin is a graduate of Harvard University and Baylor University College of Medicine. A Boston native, Dr. Mirkin did his residency at the Massachusetts General Hospital. He has served as a Teaching Fellow at Johns Hopkins Medical School, Assistant Professor at the University of Maryland, and Associate Clinical Professor in Pediatrics at the Georgetown University School of Medicine. He has run more than forty marathons and is now a serious tandem bicycle rider with his wife, nutritionist Diana Mirkin.