By 1982, salt was called ‘A New Villain’ on the cover of TIME magazine. The 1988 publication of the INTERSALT study seemed to seal the deal. This massive study involved 52 centers in 32 countries and laboriously measured salt intake and compared this to blood pressure. Across all populations, the higher the salt consumption, the higher the blood pressure. Seemed like a slam dunk, although the effect was quite small. A 59% reduction in sodium intake would be predicted to lower the blood pressure by only 2 mmHG. If your systolic blood pressure was 140, severely restricting your salt could lower that to 138. However, no data existed as to whether this would translate into less heart attacks and strokes. But based on this influential study, in 1994 the mandatory Nutrition Facts Label proclaimed that Americans should only eat 2,400 mg per day (about one teaspoon of salt). Yet the stubborn fact remains that virtually every healthy population in the world eats salt at levels far above that recommendation. The dramatic improvements in health and lifespan of the last 50 years have occurred during a period where almost everybody was considered to be eating too much salt.
Our belief in the benefits of low salt consumption are largely based on mis-information and myth-information. The underlying assumption of the salt reduction advice is that eating too much salt is a recent phenomenon brought on by the increased consumption of processed foods. Dahl, for example, claimed in his writings that widespread use of salt as a condiment was uncommon until modern times.
Data from military archives going back to the war of 1812 show that soldiers and presumable the rest of Western society ate between 16 and 20 grams of salt per day. During the war of 1812, soldiers maintained a daily consumption of 18g/ day despite high cost. American prisoners of war complained bitterly that their 9 g/day of salt was ‘scanty and meager’. It was only after World War II, when refrigeration replaced salting as the primary means of preserving food that Americans lowered their average salt intake to 9g/ day where it has remained since. During that period pre-WWII, there was no concern of excess deaths from heart disease, stroke or kidney disease — the main things used to scare us into lowering our salt intake.
The Tides Turn
From its very inception, there were problems with the hypothesis that lowering salt could save lives. Dahl failed to notice all the various high-salt eating cultures that had no adverse health consequences. The…