Salt and Blood Pressure

A model of Na-K-2Cl cotransport.

Salt and sodium are commonly blamed for high blood pressure. Do not confuse the two terms. Common table salt is sodium chloride, a simple chemical compound. Sodium is a highly reactive element and is not found free in nature. "Salt" is not synonymous with the term “sodium.”

Salt vs. Sodium
A list of conversions for salt and sodium appears below:

• 1 mmol sodium = 23 mg sodium

• 1 g sodium = 43.5 mmol sodium

• 1 g salt (sodium chloride) = 390 mg sodium

• 1 tsp salt = 6 g salt ≈ 2,400 mg sodium = 104 mmol sodium = 104 mEq sodium

To convert mmol to mg of sodium, chloride, or sodium chloride, multiply mmol by 23, 35.5, or 58.5 (the molecular weights of sodium, chloride, and sodium chloride), respectively. - CDC

mmol stands for millimol, or one one-thousandth of a mole. A mole of a chemical compound has as many grams as the atomic weight of the compound. Sodium has an atomic weight of 22.98976928, call it 23. Chlorine makes up the chloride part of sodium chloride and has an atomic weight of 35.45, call it 35. I don't have a scale that will measure fractions of a gram, and if we're talking about the amount of food you eat, it's not significant. Anyway, one mole of table salt is 58 grams, which is 2 ounces, which is why all the numbers in the list above use the milli- prefix.

The mEq unit label in the last line of the above chart stands for milliequivalence. An Equivalence is one mole of a substance times the valance of the ion in question. Sodium ions have a valance of one, so one mole of sodium is the same as one equivalence. Calcium ions have a valance of two, so one mole of calcium is two equivalences. Wikipedia has an article. The Ohio State University School of Veterinary Medicine also has a page on the topic.