We know that the body will respond in some way to everything that is put into it, no matter whether the substance is ingested, injected, or inhaled. Physiological responses can cause symptoms. Yet the physiological responses themselves are always perfect for the stimulus. We need to consider how the body responds to stimuli such as ingested, injected, or inhaled elements, not what the stimuli or elements are capable of achieving. This differentiation is a fine but vital line of distinction.
Consider a response you may have had to a situation in your childhood: While attending a large Fourth of July picnic, you revel in the vast array of “wonderful” food available: hot dogs, hamburgers, baked beans, potato salad, coleslaw, corn on the cob, soft-drinks, chips, homemade ice cream, and roasted marshmallows. In your enthusiasm, you “chow down” on at least a little of everything—you eat your way through the day. At the end of the day, the childhood culinary delights are topped off with a watermelon feast, and you start home more than amply satisfied—you’re “full.”
Soon, your stomach begins to feel queasy. Then you begin to feel sick. Then you vomit. Your concerned family can’t understand why you are sick and fret that some of the food may have been “bad.” Actually, after you “get sick,” you feel pretty good. Your body has relieved itself of the stimulus that resulted in vomiting. The stimulus that caused the vomiting was really a response to another stimulus. Your body responded to the stimuli of too many different types of food in your stomach: some protein, some carbohydrates, and lots of sugar. Your digestive system was being called on to process too many different types of substances at once. It responded to the internal mayhem by eliminating some of the stimuli, which were creating conflicting demands.
There was nothing wrong with the picnic foods. Your body could have handled each of them individually. Ordinarily, the effect of individual foods on your body would be outwardly uneventful. However, the response of your body to the combined concoction was volcanic. Laboratory analysis of any of the individual picnic foods would have shown that none contained elements that would cause physiological distress. Yet the response the body was required to
make in order to maintain homeostatic balance was unpleasant for the moment.
What does all of this stimulus/response discussion have to do with sodium and salt? Just as your body had to respond to the cataclysmal concoction of the picnic food, it must respond to salt. Since salt can’t be used, your body must “defend” against it. The first defense against salt is dilution, and dilution contributes to high blood pressure. The researchers found that the men’s blood pressure rose when they consumed additional sodium chloride, but it didn’t rise when they consumed sodium citrate.