June 24, 2010

Salt of the Earth: One Size Fits None

Hatched by Dafydd

The Centers for Disease Control and Prevention (the CDC -- "Prevention" is evidently an afterthought) released a study today announcing the horrible truth: nearly 70% of Americans eat more salt than the CDC recommends:

Health officials currently say no adult should eat more than a teaspoon of salt each day. They go on to advise that 70 percent of adults - including people with high blood pressure, all African-Americans and everyone over 40 - should actually limit their salt intake to a more restrictive two-thirds of a teaspoon.

Sodium increases the risk of high blood pressure, which is major cause of heart disease and stroke. Salt - or sodium chloride - is the main source of sodium for most people.

I smell the distinct burnt-almond odor of question begging. Let's grant that the study is accurate that 70% of Americans eat more than a teaspoon, or 2,300 mg, of sodium per day (that figure is recommended for healthy non-blacks aged 2 to 39), or 1,500 mg for those with high blood pressure (essential hypertension), blacks, and for anyone 40 and over. I promise I believe them! That's a miniscule quantity of salt; I certainly eat far more.

But so what? There are more important questions:

  • How did the CDC settle on those particular numerical targets?
  • Why on earth would the targets be the same for everyone in the same demographic? Doesn't individual health -- one's own blood pressure, for example, and medical history -- along with genetics have something to do with how much salt one should eat?

You can look high and low in the AP story and find no response, nor even evidence of curiousity about either question; reporter Mike Stobbe simply accepts the statements as if brought down from Mt. Sinai. Still puzzled, I Googled around to find the government's own report on this vital issue. I finally unearthed a document titled Dietary Guidelines for Americans 2005, published by the U.S. Department of Health and Human Services (HHS). On page 40 (page 51 of the pdf), we find this wildly illuminating explanation:

Reducing salt intake is one of several ways that people may lower their blood pressure. The relationship between salt intake and blood pressure is direct and progressive without an apparent threshold. On average, the higher a person’s salt intake, the higher the blood pressure. Reducing blood pressure, ideally to the normal range, reduces the risk of stroke, heart disease, heart failure, and kidney disease.

If you're reducing blood pressure "ideally to the normal range," it must have been higher than normal to begin with. But what about those Americans whose pressure is already normal?

If we take the HHS guidelines at face value, we must believe that, for those of us who eat a high-salt diet but nevertheless have completely normal blood pressure, cutting our salt intake down to HHS's recommendation would leave us with abnormally low blood pressure, causing enervation, dizziness, and fainting spells.

Is that what they mean when they say high-salt diets raise blood pressure for everyone? Then it's a good thing I eat so much salt!

Of course, the reality is that the HHS claim is complete baloney: I have in the past deliberately cut down salt (including not eating processed foods at all) for a couple of months; and I have gone through periods of eating much higher levels of salt than today; yet in all cases, my blood pressure remained just about the same and always normal. Perhaps HHS Secretary Kathleen Sebelius can give me a call and explain this anomaly.

Oh well, back to the -- salt mines. Here's the CDC's reaction to the 2005 HHS recommendations:

In 2005--2006, an estimated 29% of U.S. adults had hypertension (i.e., high blood pressure), and another 28% had prehypertension (1). Hypertension increases the risk for heart disease and stroke (2), the first and third leading causes of death in the United States (3). Greater consumption of sodium can increase the risk for hypertension (4). The main source of sodium in food is salt (sodium chloride [NaCl]); uniodized salt is 40% sodium by weight. In 2005--2006, the estimated average intake of sodium among persons in the United States aged >2 years was 3,436 mg/day (5). In 2005, the U.S. Department of Health and Human Services and U.S. Department of Agriculture recommended that adults in the United States should consume no more than 2,300 mg/day of sodium (equal to approximately 1 tsp of salt), but those in specific groups (i.e., all persons with hypertension, all middle-aged and older adults, and all blacks) should consume no more than 1,500 mg/day of sodium (6).

Notice the weasel-words in the essential link above: Eating more salt "can" "increase the risk" (a double qualifier!) of high blood pressure. Where does that come from, and exactly what does the science say?

Note the highlighted point refers to note (4) in the CDC paper; this leads us to a publication dubbed (take a deep breath) the Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (2005), which is published by the "Standing Committee on the Scientific Evaluation of Dietary Reference Intakes (the DRI Committee) of the Food and Nutrition Board, Institute of Medicine, The National Academies, in collaboration with Health Canada. This study was requested by the Federal Steering Committee for Dietary Reference Intakes, which is coordinated by the Office of Disease Prevention and Health Promotion of the U.S. Department of Health and Human Services, in collaboration with Health Canada."

Ah, back to the good old HHS again. The discussion of salt (sodium and potassium) begins on page 269; on page 270, we find the following curious discrepency:

Because of insufficient data from dose-response trials, an Estimated Average Requirement (EAR) could not be established, and thus a Recommended Dietary Allowance could not be derived. Hence, an Adequate Intake (AI) is provided.

The AI for sodium is set for young adults at 1.5 g (65 mmol)/day (3.8 g of sodium chloride) to ensure that the overall diet provides an adequate intake of other important nutrients and to cover sodium sweat losses in unacclimatized individuals who are exposed to high temperatures or who become physically active as recommended in other dietary reference intakes (DRI) reports. This AI does not apply to individuals who lose large volumes of sodium in sweat, such as competitive athletes and workers exposed to extreme heat stress (e.g., foundry workers and fire fighters). The AI for sodium for older adults and the elderly is somewhat less, based on lower energy intakes, and is set at 1.3 g (55 mmol)/day for men and women 50 through 70 years of age, and at 1.2 g (50 mmol)/day for those 71 years of age and older.

Wait... if they cannot come up with a Recommended Dietary Allowance -- then how did they come up with a Recommended Dietary Allowance of 2,300 mg? What's the relationship to the Adequate Intake (AI) number?

Amazingly enough, the number listed here as the AI, or adequate daily intake, of sodium is 1.5g... or to put it in slightly different units, 1,500 mg. Yet this is the identical number now offered by the CDC as the maximum daily intake of sodium for anyone over the age of 40. In other words, the maximum sodium they want you to eat is the bare minimum to avoid getting sick!

The page continues:

The major adverse effect of increased sodium chloride intake is elevated blood pressure, which has been shown to be an etiologically related risk factor for cardiovascular and renal diseases. On average, blood pressure rises progressively with increased sodium chloride intake. The dose-dependent rise in blood pressure appears to occur throughout the spectrum of sodium intake. However, the relationship is nonlinear in that the blood pressure response to changes in sodium intake is greater at sodium intakes below 2.3 g (100 mmol)/day than above this level.

In other words, sodium is not damaging in and of itself, but by and large only in its relation to higher blood pressure. This is important; take a mental note.

(Also, once a patient is above the CDC recommended maximum of 2,300 mg, increased sodium intake doesn't raise blood pressure as much as is does between the minimum and the maximum recommended daily intake.)

On the next page, we finally discover whence came the maximum-intake number for younger, non-black, non-hypertensive adults:

The adverse effects of higher levels of sodium intake on blood pressure provide the scientific rationale for setting the Tolerable Upper Intake Level (UL). Because the relationship between sodium intake and blood pressure is progressive and continuous without an apparent threshold, it is difficult to precisely set a UL, especially because other environmental factors (weight, exercise, potassium intake, dietary pattern, and alcohol intake) and genetic factors also affect blood pressure. For adults, a UL of 2.3 g (100 mmol)/day is set.

On an (unsalted) nutshell, they're saying that the effect of salt on blood pressure is a continuum, without any sharp dividing line between a healthy and an unhealthy amount. Therefore, the sharp dividing line is set to 2.3 g, or 2,300 mg per day, by administrative fiat.

Alert readers can be excused for sudden confusion: If the nutritionists admit they cannot find a rigid line between "tolerable" and (one presumes) intolerable levels of sodium -- then how can they draw one at 2,300 mg/day? Why there, exactly? The conundrum is easily explained:

In dose-response trials, this level was commonly the next level above the AI that was tested.

And there you have it! The origin of the 2,300 mg/day Tolerable Upper Intake Level of sodium is simply that it was the next highest number that the labs generally tested in clinical trials. Had the next number tested been 2,100 or 2,600 or 3,000, instead of 2,300, then the Standing Committee would have set that number as the Tolerable Upper Intake Level.

It's science!

To be perfectly blunt, the number 2,300 mg/day -- for younger, non-black adults who don't have hypertension -- is completely arbitrary. It's just an artifact of the testing procedure. The Standing Committee needed some number larger than bare survival-minimum, and 2,300 mg happened to be the next highest number most labs tested.

For those of us over 40, or black, or with high blood pressure, the recommended maximum isn't arbitrary; but it is miserly; it's just the minimum level to avoid the unpleasant effects caused by too little sodium: "Concerns have been raised that a low level of sodium intake adversely affects blood lipids, insulin resistance, and cardiovascular disease risk."

Thus are great nonsense pronouncements perpetrated upon the people by the federal guardians of all wisdom, the technocrats. "Healthy people mustn't eat more than a miniscule amount of salt, because unhealthy people can't!"

This reminds me of schools that ban peanut-butter and jelly sandwiches for all kids because some kids are allergic to peanuts. (Nowadays, even some airlines ban plastic packages of peanuts; a few fliers might be allergic, and in a fit of amnesia, they might wolf down a package or two before remembering. You never know!)

The publication mentions but ignores a slew of caveats about individuals:

This AI does not apply to individuals who lose large volumes of sodium in sweat, such as competitive athletes and workers exposed to extreme heat stress (e.g., foundry workers and fire fighters)....

Genetic factors also influence the blood pressure response to sodium chloride. There is considerable evidence that salt sensitivity is modifiable. The rise in blood pressure from increased sodium chloride intake is blunted in the setting of a diet that is high in potassium or that is low in fat, and rich in minerals; nonetheless, a dose-response relationship between sodium intake and blood pressure still persists....

Salt sensitivity differs among subgroups of the population and among individuals within a subgroup. The term “salt sensitive blood pressure” applies to those individuals or subgroups who experience the greatest change in blood pressure from a given change in salt intake—that is, the greatest reduction in blood pressure when salt intake is reduced.

That is, different people have different levels of blood-pressure reaction to sodium. Who'd'a thunk it?

So I ask again: Why should individuals who are not hypertensive worry about their high-salt diets? Why should the CDC set a single, "one size fits all" number that even the nutritionists -- upon whom the CDC relies -- admit is completely arbitrary and artifactual?

Worse, why should the feds start regulating salt use on the basis of such airy-fairy handwaving? Make no mistake, regulation is coming: It will begin with the feds ordering processed-foods manufacturers to use less salt; but in the end, if the Environmental Protection Agency can regulate exhaling as a "pollutant," what's to stop the FDA from regulating salt as a "poison?"

How long will it be before the FDA orders salt off grocery shelves and begins requiring us to buy it from a pharmacist -- with a doctor's prescription?

Tyranny begins when the State seizes monopoly access to a nutrient vital to life, whether carbon dioxide or sodium chloride. Mohandas Gandhi understood that much; he considered the colonial British monopoly on salt (!) to be a supreme act of oppression of the Indian people.

I'm tempted to demand the dismantling of the EPA, the FDA, and the CDC altogether; but that's pointless: It will never happen because too many Americans think that without the "invisible foot" of the federal government, we would all die tomorrow. But at the very least, the popular front for individual liberty that is fighting to hard to reduce government spending should be able to push Republicans and some Democrats into making defense of individual dietary liberty a part of their 2010 campaigns.

The assault on salt is just one more mouthful to swallow on the road to serfdom.

Hatched by Dafydd on this day, June 24, 2010, at the time of 7:48 PM

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The following hissed in response by: Michael Babbitt

The ultimate happy faced, helping hand totalitarianism. We must resist these Liberal Fascists.

The above hissed in response by: Michael Babbitt [TypeKey Profile Page] at June 24, 2010 8:56 PM

The following hissed in response by: Sashland

Thank you for your extremely detailed analysis - it reminds me that I need to intake more salt since I am working in the yard in high heat. Begs the question: how many people are harmed by NOT ENOUGH SALT?

Your comparison to peanuts, however, misses the mark: peanuts are restricted because exposure, even to only airborne particles, can cause an allergic reaction and death. Eating salt one can control - not breathing air on an airplane can be a little more difficult...
Still, I don't think we should ban ALL peanuts, though that might occur as the proper solution to some salinephobes.

The above hissed in response by: Sashland [TypeKey Profile Page] at June 25, 2010 3:15 PM

The following hissed in response by: Bart Johnson

Since we are discussing arbitrary science, did you ever wonder about that 98.6F body temperature?
The studies that came to that strange number measured the temp of a large number of people.
Since they were properly Metric, they did it in Celsius, then rounded to the nearest whole number!
The "standard" body temperature is 37.0C, which converts to our beloved 98.6F.

The above hissed in response by: Bart Johnson [TypeKey Profile Page] at June 25, 2010 8:47 PM

The following hissed in response by: Ken Hahn

It's not about salt. It's about power. The bureaucrats want the power to regulate salt for the same reason they want the power to regulate carbon ( or any other substance ). They believe they know what's best for you and they're going to make sure you do it. Even if they have to kill you in the process.

The above hissed in response by: Ken Hahn [TypeKey Profile Page] at June 26, 2010 10:22 AM

The following hissed in response by: Geoman

This is by far not the worst of it.

What if I were to tell you that cleanup levels for most hazardous chemicals are entirely arbitrary? In the 1970s the EPA was asked to develop cleanup levels for a number of toxic compounds - what concentration in the soil and water was hazardous to human health and the environment, and what was okay? There are huge cost implications here - even a very small change in the concentrations can save or cost millions.

Given that there was limited data available for many of these compounds, when in doubt (which was frequently), the EPA just defaulted to the detection limits. That's right, whatever the detection limit was, that became the default cleanup level for that compound. Some compounds were much easier to detect than others, so had much lower cleanup levels based solely on that criteria.

Flash forward from the late 1970s to 2010. Technology has improved significantly, and so has our toxicity data. We can now detect concentrations of toxic compounds far below their previous detection limits, and we know a great deal more about their toxicity in the environment. A few compounds were found to be more toxic than first thought. Those cleanup levels have largely decreased. Many others have been found to be less toxic. Despite this, little if any change has occurred to cleanup levels - most remain at their 1970s detection limits, which of course, never had any scientific basis to begin with.

The above hissed in response by: Geoman [TypeKey Profile Page] at June 28, 2010 4:45 PM

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