& Joannie Dobbs Wednesday,
March 18, 1998
Balancing the latest news about
For decades, our brains have been massaged by the media into accepting the message that, “Low salt is good for you.”
Then, last week we got the latest news about a large study on more than 11,000 people concluding that results “. . . do not support current recommendations for routine reduction of sodium consumption, nor do they justify advice to increase salt intake or to decrease its concentration in the diet.”
At first this sounds like double-speak, but it actually makes some sense. This study, reported in the Lancet medical journal by Michael Alderman and co-authors, asked people back in the early 1970s to write down what they ate for the last 24 hours. Over the next 20 years, there were fewer deaths in the group that reported eating the most salt (top 25 percent) than in the group that reported eating the least (lowest 25 percent).
Since this type of study does not demonstrate “cause and effect,” but rather just a relationship, the authors could reasonably state that their results do not support broad public health recommendations for salt reduction. However, their study is not the type that can justify recommending that people increase their salt intake (or decrease it either).
It has been known for quite some time that some people with high blood pressure are “salt sensitive.” If you reduce the salt in their diet, their blood pressure will drop.
However, many people with hypertension are not salt sensitive. So, does this mean that the public health recommendations to reduce salt intake are ridiculous for most of us and we should go ahead and load on the salt? Not necessarily.
It is reasonable for most of us to avoid high salt intake, since it has been associated with problems other than hypertension. Examples include an increased risk of developing osteoporosis and stomach cancer.
What this recent study seems to say is that salt does not seem to be the monster some have made it out to be. The study is important since it was based on a large number of people.
However, it used a somewhat crude estimate of salt intake, asking people what they ate for the past 24 hours. And, it is possible that those with the poorest health at the start of the study had already cut back on salt. In other words, some low salt eaters may have died due to health problems unrelated to salt. They may have eaten less salt thinking it would help.
There is much variability in salt needs among individuals. Some experts have cautioned that over-restriction of salt intake could be harmful. In fact, neurologists are concerned if blood pressure gets too low or too high. Either extreme can be dangerous for their stroke patients. The risks of long-term high blood pressure are substantial, but excessively low blood pressure can be risky too.
Much of the variability in salt needs is due to exercise. An hour of exercise in Hawaii can easily result in a 4-gram loss of salt through sweat. This can vary from one person to another.
Still, the standard recommendation for sodium intake is to not exceed about 6 grams of salt (a rounded teaspoon of salt, which contains 2,400 milligrams of sodium) per day.
This public health recommendation is made for the average lightly to moderately active individual. People who are very active can have daily sodium needs that are greater than the standard recommendation.
The “take-home” message is that the sodium is an essential nutrient. It is healthy to get enough of it. Getting too much is not good.
Alan Titchenal, Ph.D., C.N.S. and Joannie Dobbs, Ph.D., C.N.S.
are nutritionists in the Department of Human Nutrition, Food and Animal Sciences,
College of Tropical Agriculture and Human Resources, UH-Manoa.
Dr. Dobbs also works with the University Health Service
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