The Truth About Salt: Stinting Is Dangerous Too

Experts agree that too much salt can jack up blood pressure - but too little salt can be just as deadly.

David Bachar

All health experts agree too much salt is bad for you. It increases blood pressure, which can lead to cardiovascular disease, stroke and death.

But how much salt is right for you? It is widely accepted that “salt is bad,” but in fact too little salt in one’s diet may be just as bad.

In fact, after all these decades, salt recommendations are still a matter of considerable debate.

The influential Current Dietary Guidelines for Americans suggests limiting sodium intake to less than 2,300 mg a day. (One salt molecule consists of one sodium atom bound with one chloride atom; hence 2,300 mg of sodium translates to 6,100 mg of actual salt, or about 1 teaspoon.)

People at greater risk for hypertension, such as those aged 51 and older, those already with hypertension, and individuals with diabetes and chronic kidney disease are advised to decrease their sodium consumption even further to 1,500 mg a day.

This group constitutes about 50% of the American population, so we are talking about a lot of people cutting back on a lot of salt.

Recommendations from the Israeli Health Ministry are even more restrictive. All Israelis are advised to cut back to 1,500 mg of sodium per day, with an absolute daily maximum of 2,400 mg (just under one teaspoon of salt).

When metabolism runs amok

How did the experts arrive at these figures? The influence of sodium consumption on blood pressure was known from short-term research studies. So, also, was the relationship between blood pressure and cardiovascular disease. It was not difficult, therefore, to join these two data sets together, assuming a linear relationship between blood pressure and cardiovascular events.

Therein lies the problem. The relationship between blood pressure and cardiovascular events is not linear, and recent studies suggest not a decreased but increased risk of death for people consuming less than 3,000 mg of sodium a day.

To clarify this issue, the American government requested their Institute of Medicine convene an expert panel to review all recent scientific evidence.

This panel issued a highly controversial report. It agreed that reducing very high sodium intake levels to moderate levels improves health.

However, insufficient evidence was found to justify lowering sodium consumption below 2,300 mg a day for either low or high-risk individuals, since there is some evidence for adverse health effects in the sodium range of 1,500 to 2,300 mg a day for those with diabetes, kidney disease and heart disease. The reason for this seems to be that very low salt diets may lead to a compensatory hormonal response, and this can be harmful.

The committee did not provide a healthy intake range, as this was not part of their mandate and would in any case have been difficult to do from the studies they were reviewing.

Israelis are eating too much salt

Meanwhile, a new prospective study has just been published in the prestigious New England Journal of Medicine that examined cardiovascular events and death from 17 countries in relation to urinary sodium excretion. Sodium intake can be calculated from urinary sodium. The results were like a letter J, producing a so-called J-shaped curve.

Too much sodium and too little sodium increased risk, and in-between was a safe zone. And the calculated safe zone in this study? 3,000 to 6,000 mg of sodium a day, which is about 1¼ teaspoon to 2½ teaspoon of salt.

This is unlikely to be the last word on the matter, and more research is clearly needed, but is probably getting close to the truth.

What does this mean for everybody? It means that extremely low sodium diets may not be a good thing, even if one has hypertension and kidney disease. It also means that the Israeli recommendations are probably too restrictive, although this is somewhat theoretical as such low sodium levels are difficult to achieve with the foods that most people eat.

Finally, everyone whose salt consumption is within the calculated “safe zone” need do nothing.

Average sodium consumption in the USA is about 3,400 mg of sodium a day. Average sodium consumption in Israel is about 3,750 mg a day, so Israelis are in about the same ballpark as Americans.

Nevertheless, this figure is an averageL 50% of the population has to be eating more than the average, and included in this 50% are a lot of people eating way beyond the safe zone.

Drop that cracker

About 75% of salt consumption comes from processed foods, 10% from natural foods and 15% from a saltshaker or home cooking, so that processed foods are the main culprits for a high-sodium diet. If you are eating a lot of processed meats and sausages, salty snack foods such as crackers and potato chips, soy sauce, and soup mixes, you are probably a high sodium consumer. These foods have few redeeming features and are best eliminated from one’s diet, or at least severely curtailed.

Lowering salt intake, if done gradually is not difficult, since taste buds adjust over time.

Other foods that may have a high salt intake include some cheeses, TV dinners and frozen meals, salted nuts, olives, pickles, breakfast cereals and breads.

In contrast to sodium, potassium-rich foods influence blood pressure in a positive way. Potassium is found in fruits and vegetables. These foods should already be part of a healthy diet, and may be more helpful for blood pressure than aggressive sodium reduction alone.

Some countries have embarked on serious educational programs to instruct their population about the dangers of excess salt, including the labeling of high-salt foods and requesting food companies to voluntarily reduce the sodium content of their processed foods. This strategy has been remarkably successful in Finland, where since the 1970s, average blood pressure has fallen by 10 mm, and stroke and coronary-artery mortality by 70%-80%.

Israel is now following approximately the same path. Food companies are being voluntarily asked to reduce the amount of salt in their processed foods, and foods that accomplish this will be distinguished. However, high-salt foods are not being labeled, and the Health Ministry is relying on health professionals to advise their patients about lower salt alternatives. It is also working with bakeries on lowering salt in their offerings and with slaughterhouses, to reduce the amount of salt used in the kosherizing process, the ministry says. Whether these steps will be as effective as the measures taken in Finland remains to be seen.

Despite the controversies, there is no doubt that a lot of Israelis are eating far too much salt. For their own health, they need to cut back.

References for this article can be found on Dr. Arnold Slyper’s website eatforhealth.org.