Salt and High Blood Pressure: Does Salt Make Us Hypertensive? And If Not, What Is the Real Problem?
The salt and high blood pressure theory dominates our thinking about hypertension. But might there be a far more significant dietary cause of hypertension? And could the evidence linking sodium intake to blood pressure possibly be flawed to such an extent that the theory essentially collapses?
Before we examine evidence for and against the "salt and high blood pressure" theory, let's briefly bring the discussion back to the main question posed by this website: What makes us fat?
The Caloric Balance Hypothesis insists that excess calories lead to obesity; but it tells us nothing about why obesity and hypertension might associate.
The Lipophilia Hypothesis insists that fat tissue disregulation drives us to accumulate a positive balance of calories; and it further suggests that hypertension and obesity can both be manifestations of the same metabolic/hormonal dysfunction.
For our second hypothesis to succeed, its defenders must do two things. First, we must muster evidence that the "salt and high blood pressure" theory is wrong, since our favored hypothesis tells us that carbs, not salt, cause high blood pressure. Second, we must show that carbohydrate disease/hyperinsulinemia can account for the vast majority of cases of hypertension.
1. Gary Taubes lays out a compelling series of arguments along these lines in his book, Good Calories Bad Calories (pp 145-150). He discusses how we developed the belief that sodium intake caused hypertension; how abundant evidence contradicts that theory; and how laboratory evidence supports the contention that diets high in carbohydrates can raise blood pressure.
He emphasizes that carbs drive water retention by preventing sodium excretion. When you restrict carbs from the diet, this has an effect similar to that of a diuretic. In other words, it encourages the kidneys to get rid of sodium along with water.
Taubes presents such a vivid, convincing and evidence-based argument against the salt and high blood pressure theory of hypertension, that it seems -- to a non-expert at least -- to completely refute the theory.
2. Even better, check out this online article by Taubes. If you read (and comprehend) this entire thing, chances are that you will come away passionately convinced that salt in the diet cannot be the primary cause of hypertension.
3. Taubes, obviously, isn't the only one to make many of these points. Another good reference is Life Without Bread. On pages 96-98, the authors discuss their work treating patients with hypertension with a low carb diet:
"Results from the study found that the systolic blood pressure dropped immediately... this same result was observed in 1952 by a Delaware physician, who noted that high blood pressure dropped under a lower carbohydrate diet, and it was parallel to weight loss."
4. Here's another article about carbs, salt and high blood pressure written by a medical professional: "The case for low carbohydrate diets in diabetes management."
"A high carbohydrate diet raises postprandial [after meal] plasma glucose and insulin secretion, thereby increasing the risk of CVD, hypertension, dyslipidemia, obesity, and diabetes... The apparent failure of the traditional diet, from a public health point of view, indicates that alternative dietary approaches are needed."
5. And here's another article that supports the general points being made about salt and high blood pressure theory:
"Obesity has reached epidemic proportions [in the United States and the UK], and the enormously high levels of hypertension among the population appear to follow this trend closely."
The article also says:
"We all know what causes high blood pressure, don't we? It's because we eat too much salt. Well, that might be the politically correct line but it doesn't square with the scientific evidence."
The close correlation between hypertension and obesity should have prompted good scientists to search for common underlying themes of the diseases. Researchers will tell us that hyperinsulinemia puts people at risk for both obesity and hypertension. They will also admit that overeating refined carbohydrates causes us to secrete massive amounts of insulin.
So why not put two and two together and posit that the most likely explanation for our observations is that high carb diets (and other insulinogenic factors) cause both obesity and hypertension? Why are we all so stuck on this salt and high blood pressure theory?
Why? Perhaps because if researchers admitted this connection, it would mean abandoning the Caloric Balance Hypothesis - the idea that calories "count."
Did you enjoy this article? It's been over 4 years since I wrote it or edited any of the other content you'll find on this site. :]
During this hiatus, I've had the privilege of talking about these concepts with many renowned authorities in the fields of diet and health, including Gary Taubes... as well as many of his critics.
After researching and thinking for four years, I came to a startling revelation about how to simplify the fat loss question. I call this concept "The Black Box."
I explain it all in a free short report, which you can download via the form below. Check it out! It's a legitimately new idea, and a lot of people (including many respected obesity researchers) have found it compelling. Thank you! - Adam
1. Taubes, Gary. "Good Calories, Bad Calories." pp 145-150. New York: Knopf (2007).