The theory is based on the observation that increased sodium intake is associated with an increase in blood pressure. It is in a modest way. It is widely preached that hypertension is associated with an increased risk of cardiovascular disease, kidney disease, and stroke. This is true. The assumption is therefore then made that by reducing dietary sodium we will reduce hypertension and thus reduce these untoward effects. This has not been demonstrably or conclusively shown, but it makes for great slogans, off the cuff advice, and lazy recommendations. It also makes for poor publicly mandated policy.
Here is where I can comment -- as a working chef -- because this proposal is especially grievous when it comes to regulating an art form like restaurant cookery. I am not talking about prepackaged and assembled food-like products. I am talking about chefs creating real food from real ingredients. Let us examine some data:
- Over 70 percent of daily sodium intake comes from processed, pre-packaged, and prepared foods.
- Only about five percent of daily sodium intake comes from salt added to properly season food that is freshly cooked
- Even if you add salt at the table, this makes up only about six percent of daily intake
- Another 10 percent (roughly) is inherent in food itself.
- The government's own recommendations (PDF) note that the hypertensive effect of excess sodium consumption is manifest at levels above six grams per day.
- The previous federally recommended amount of daily sodium consumption was around a teaspoon, about 2.3 grams. The current recommendations are for 1.5 grams daily.
- The average American currently consumes around 3.4 grams of sodium per day.
The governmental recommendations are predicated on the assumption that the "taste for sodium is acquired and can be modified" (PDF). The reason sodium and chloride (the constituents of what we refer to as 'salt') are classified as essential minerals is that we require them to live. We are physiologically programmed, like a gazelle on the Serengeti, to seek out and consume salt should we not get a sufficient amount in our diet. It is hardly an acquired taste like caviar or country music.
Additionally, the government asserts that since "consuming less salt or sodium is not harmful, it is understandable why the Federal Government recommends that healthy normal individuals moderate their salt and sodium intake." The only problem here is that many studies, some acknowledged in the government's own position paper, have questioned the safety of too much sodium restriction -- or even any restriction at all. Several papers published in 2010 and 2011 have continued to raise this question -- even as the government forges ahead with publicly mandated policy.
A study published in 2011 by Dr. Jan Staessen followed about 3,700 patients for eight years and divided them into tertiles of low, medium, and high sodium intake. The highest death rate was in the group with the lowest sodium intake; the lowest death rate was in the group with the highest sodium intake. An even larger study was done by Dr. Salim Yusef and his group out of McMaster University in Canada and published in The Journal of the American Medical Association in 2011. Over 30,000 people were studied for about four years. They examined low sodium intake (less than 2.3 grams), moderate intake (2.3 to seven grams), and high intake (more than seven grams) and found at the extremely high levels there was an increased risk of cardiovascular events. However, they also found that at the low level of sodium intake there was an increased risk of cardiovascular death and increased risk of hospitalization for heart failure. The low sodium intake group also had a 2.5 percent increase in their cholesterol and a seven percent increase in their triglyceride levels. The moderate sodium intake group (consuming between 2.3 and seven grams of sodium per day -- well within the daily consumption of the average American) had the lowest risk of cardiovascular morbidity and mortality.