The Sodium Problem: Gimme a Bag of Sea-salt and Black Pepper
Posted: Tuesday, July 26, 2011
by Jack H. Schick
Way back in ’61, I was sitting in my fourth grade classroom looking at the Mercator projection map of the world pinned to the wall. I noticed that the east coast line of South America would fit neatly against the west coast line of Africa--if only the continents could move. I mentioned my observation to Miss Johnson. She told me it was a silly idea and I should pay attention to the lesson. Now, of course, we know it was not a silly idea. Wegener’s “crazy theory” has long since been accepted as a geologic fact. The continents do move. The scientific world experienced a complete paradigm shift since then.
Most often erroneous scientific theories and practices develop because of limited knowledge, misinterpreted data or faulty experimentation. A contemporary example of this is the commonly held belief that a reduction in sodium (salt), consumption will reduce the probability of developing hypertension, heart disease and the chance of having a stroke. It appears that our knowledge about sodium intake remains limited and our experimental data is often contradictory. However, the paradigm has been established. “Everyone knows” too much salt is bad for you. But, “everyone knew” that continents could not move and bleeding patients was good medical practice.
The over consumption of salt became a major medical concern after a study done in the early 1970’s by Lewis Dahl of the Brookhaven National Laboratory. His experiments showed “unequivocal evidence” that salt caused hypertension (high blood pressure). He fed rats the human equivalent of 500 grams of sodium a day (the average American consumes about 3.5 grams a day). In almost every case, the rats developed high blood pressure. Dahl also accumulated data that showed that countries with high salt consumption-like Japan- tend to have more cases of high blood pressure and more strokes per capita.
A follow up study published in the American Journal of Hypertension could not confirm Dahl’s associations when sodium intake and hypertension were compared within a given population group. The new findings suggested that genetic or cultural factors were as likely to contribute to high blood pressure as salt consumption. Nevertheless, in 1977 the U.S. Senate’s Select Committee on Nutrition and Human Needs recommended that Americans reduce their salt intake by 50 to 85%, based mostly on Dahl’s studies.
Scientific methods and tools have become much more comprehensive and precise since then, but a correlation between salt intake and poor health remains difficult to confirm. A large 1988 study compared sodium intake with blood pressure in subjects from 52 international research centers. They found little or no relationship between the two. In fact, the subjects that ate the most salt had a lower median blood pressure than the subjects who ate the least. In 2004, the Cochrane Collaboration, an independent organization partly funded by the U.S. Department of Health and Human Services, published data gathered in 11 long-term salt reduction trials. They found that low salt diets reduced systolic blood pressure (top number), by 1.1 millimeters of mercury and the diastolic (lower) number by about 0.6 mmHg; equivalent to lowering a 120/80 reading to 119/79-hardly worth the effort or the bland French fries. The findings confirmed a 2003 Cochrane short term study conclusion that as far as high blood pressure is concerned, “there is little evidence for long-term benefit from reducing salt intake.”
A direct relationship between sodium intake and heart disease has not been found, either. A 2006 study by the American Journal of Medicine compared the daily sodium intake of 78 million Americans to their risk of dying from heart disease over a 14 year period. It actually found that the more sodium people ate the less likely they were to die from heart disease. A 2007 study of 1500 older people by the European Journal of Epidemology that lasted five years also found no association between sodium intake levels and the risk of coronary vascular disease or death.
It seems that for every study that finds salt to be unhealthy, there is another couple that finds it is not. The human kidney is “designed” to maintain a certain salt level in the blood. It will vary the amount it excretes based on the amount taken in. Individuals’ kidneys function differently and people react differently to sodium. A 1987 study published in the Journal of Chronic Diseases reported that the number of people who experienced a spike in blood pressure after eating high-salt diets was almost equaled by the number of people who experienced a drop in blood pressure.
The paradigm shift prompted by the original Dahl study has convinced most of the world that salt is dangerous to human health. Contradictory data is ignored or minimized. In April of 2010, the Institute of Medicine urged the U.S. Food and Drug Administration to regulate the amount of salt food manufacturers can put into products because of the “undeniable” health hazard of sodium. Based on debateable data, Big Brother is getting read to step in and regulate peoples' behaviors once again.
Sometimes I don’t know what to believe. Half the time, when I look at those famous trick pictures, I see the white vase, the other half I see the two black faces. Sometimes I see the duck, sometimes I see the rabbit. I sure thought those coast lines of Africa and South America looked suspicious, but the wise old teacher told me it was silly. Now, I’m pretty much convinced it’s the shrill shouting and fanatical advocacy of self-appointed know-it-alls coupled with the meddling in my private life by the government that is causing my high blood pressure, not the sea-salt and black pepper potato chips I’m so fond of.
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Top-level comments on this article: (2 total)Thanks for this article. It helped me answer questions I have been having. Good job.Thanks for reading and commenting
I do with salt intake, what I do with most everything else- Listen to what my body tells me it needs- at times, I feel a real craving for salty foods-so I happily supply what my body asks for- the salt craving is satisfied and balanced again. Same thing with sugar and other things. Of course the body must be operating in a healthy normal manner before you can trust these signals, but if it is..they do work..just stop-look and listen. I liked this article- my mind found it satisfying. Thanks Jack- Always- EllaThanks for readign and commenting, Ella
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