Tag sodium

The NaCl Debacle Part 2: We don’t need no stinkin’ science!

Adele Hite, PhD MPH RD 101 Comments

Sodium-Slashing Superheroes Low-Sodium Larry and his bodacious side-kick Linda “The Less Salt the Better” Van Horn team up to protect Americans from the evils lurking in a teaspoon of salt!
(Drawings courtesy of Butcher Billy)

Yesterday, we found our Sodium-Slashing Superheroes Larry and Linda determined to make sure that no American endangered his/her health by ingesting more than ¾ of a teaspoon of salt a day. But recently, an Institute of Medicine report determined that recommendations to reduce sodium intake to such low levels provided no health benefits and could be detrimental to the health of some people. [In case you missed it and your job is really boring, you can read Part 1 of the NaCl Debacle here.]

Our story picks up as the 2010 USDA/HHS Dietary Guidelines Advisory Committee, fearlessly led by Linda and Larry, arrives at the foregone conclusion that most, if not all, US adults would (somehow) benefit from reducing their sodium intake to 1500 mg/day.  The American Heart Association, in a report written by—surprise!—Larry and Linda, goes on to state that “The health benefits [of reducing sodium intake to 1500 mg/day] apply to Americans in all groups, and there is no compelling evidence to exempt special populations from this public health recommendation.”

Does that mean there is “compelling evidence” to include special populations, or for that matter ordinary populations, in this 1500 mg/day recommendation? No, but who cares?

Does that mean there is science to prove that “excess” sodium intake (i.e. more than ¾ of a teaspoon of salt a day) leads to high blood pressure and thus cardiovascular disease, or that salt makes you fat, or that sodium consumption will eventually lead to the zombie apocalypse? No, no, and no—but who cares?

Larry and Linda KNOW that salt is BAD. Science? They don’t need no stinkin’ science.

Because the one thing everyone seems to be able to agree on is that the science on salt does indeed stink. The IOM report has had to use many of the same methodologically-flawed studies available to the 2010 Dietary Guidelines Advisory Committee, full of the same confounding, measurement error, reverse causation and lame-ass dietary assessment that we know and love about all nutrition epidemiology studies.  But the 2010 Dietary Guidelines Advisory Committee didn’t actually bother to look at these studies.

Why not?  (And let me remind you that the Dietary Guidelines folks usually <heart> methodologically-flawed study designs, full of confounding, measurement error, reverse causation and lame-ass dietary assessment.)

First, a little lesson in how the USDA/HHS folks create dietary guidance meant to improve the health and well-being of the American people:

  1. Take a clinical marker, whose health implications are unclear, but whose levels we can measure cheaply and easily (like blood pressure, cholesterol, weight).
  2. Suggest that this marker—like Karnac the Magnificent—can somehow predict risk of a chronic disease whose origins are multiple and murky (like obesity, heart disease, cancer).
  3. Use this suggestion to establish some arbitrary clinical cut offs for when this marker is “good” and “bad.” (Note to public health advocacy organizations: Be sure to frequently move those goalposts in whichever direction requires more pharmaceuticals to be purchased from the companies that sponsor you.)
  4. Find some dietary factor that can easily and profitably be removed from our food supply, but whose intake is difficult to track (like saturated fat, sodium, calories).
  5. Implicate the chosen food factor in the regulation of the arbitrary marker, the details of which we don’t quite understand. (How? Use observational data—see methodological flaws above—but hunches and wild guesses will also work.)
  6. Create policy that insists that the entire population—including people who, by the way, are not (at least at this point) fat, sick or dead—attempt to prevent this chronic disease by avoiding this particular dietary factor. (Note to public health advocacy organizations: Be sure to offer food manufacturers the opportunity to have the food products from which they have removed the offensive component labeled with a special logo from your organization—for a “small administrative fee,” of course.)
  7. Commence collecting weak, inconclusive, and inconsistent data to prove that yes indeedy this dietary factor we can’t accurately measure does in fact have some relationship to this arbitrary clinical marker, whose regulation and health implications we don’t fully understand.
  8. Finally—here’s the kicker—measure the success of your intervention by whether or not people are willing to eat expensive, tasteless, chemical-filled food devoid of the chosen food factor in order to attempt to regulate the arbitrary clinical marker.
  9. Whatever you do, DO NOT EVER measure the success of your intervention by looking at whether or not attempts to follow your intervention has made people fat, sick, or dead in the process.
  10. Ooops. I think I just described the entire history of nutrition epidemiology of chronic disease.

Blood pressure is easy to measure, but we don’t always know what causes it to go up (or down). There is no real physiological difference between having a blood pressure reading of 120/80, which will get you a diagnosis of “pre-hypertension” and a fistful of prescriptions, and a reading of 119/79, which won’t.  Blood pressure is not considered to be a “distinct underlying cause of death,” which means that, technically, no one ever dies of blood pressure (high or low). We certainly don’t know how to disentangle the effects of lowering dietary sodium on blood pressure from other effects (like weight loss) that may be related to dietary changes that are a part of an attempt to lower sodium (and we have an embarrassingly hard time collecting accurate dietary intake information from Food Fantasy Questionnaires anyway). We also know that individual response to sodium varies widely.

So doesn’t it make perfect sense that the folks at the USDA/HHS should ignore science that investigates the relationship between sodium intake and whether or not a person stayed out of the hospital, had a heart attack, or up and died? Well, it doesn’t to me, but nevertheless the USDA/HHS has remained obsessively fixated on one thing and one thing only, what effects reducing sodium has on blood pressure,  and they pay not one whit of attention to what effects reducing sodium has on, say, aliveness.

So let’s just get this out there and agree to agree: reducing sodium in most cases will reduce blood pressure.  But then, just to be clear, so will dismemberment, dysentery, and death.  We can’t just assume that lowering sodium will only affect blood pressure or will only positively affect health (I mean, we can’t unless we are Larry or Linda). Recent research, which prompted the IOM review, indicates that reducing sodium will also increase triglyceride levels, insulin resistance, and sympathetic nervous system activity. For the record, clinicians generally don’t consider these to be good things.

This may sound radical but in their review of the evidence, the IOM committee decided to do a few things differently.

First, they gave more weight to studies that determined sodium intake levels through multiple high-quality 24-hour urine collections. Remember, this is Low-Sodium Larry’s favorite way of estimating intake.

Also, they did not approach the data with a predetermined “healthy” range already established in their brains. Because of the extreme variability in intake levels among population groups, they decided to—this is crazy, I know—let the outcomes speak for themselves.

Finally, and most importantly, in the new IOM report, the authors, unlike Larry and Linda, focused on—hold on to your hats, folks!—actual health outcomes, something the Dietary Guidelines Have. Never. Done. Ever.

The IOM committee found, in a nutshell:

“that evidence from studies on direct health outcomes is inconsistent and insufficient to conclude that lowering sodium intakes below 2,300 mg per day either increases or decreases risk of CVD outcomes (including stroke and CVD mortality) or all-cause mortality in the general U.S. population.”

In other words, there is no science to indicate that we all need to be consuming less than ¾ of a teaspoon of salt a day. Furthermore, while there may be some subpopulations that may benefit from sodium reduction, reducing sodium intake to 1500 mg/day may increase risk of adverse health outcomes for people with congestive heart failure, diabetes, chronic kidney disease, or heart disease. (If you’d like to wallow in some of the studies reviewed by the IOM, I’ve provided the Reader’s Digest Condensed Version at the bottom of the page.)

Of course, the American Heart Association, eager to provide the public with the most up-to-date recommendations about heart health as long as they don’t contradict outdated recommendations of which the AHA is fond, responded to the IOM report by saying, “The American Heart Association is not changing its position. The association rejects the Institute of Medicine’s conclusions because the studies on which they were based had methodological flaws.”

Um, hello AHA? Exactly what completely non-existent, massive, highly-controlled and yet highly-generalizable randomized controlled trials about sodium intake and health effects were you planning on using to make your case? I believe it was the AHA that mentioned that “It is well-known, however, that such trials are not feasible because of logistic, financial, and often ethical considerations.” Besides, I don’t know what the AHA is whining about. The quality of the science hardly matters if you are not going to pay any attention to it in the first place.

No, folks that giant smacking sound you hear is not my head on my keyboard. That was the sound of science crashing into a giant wall of Consistent Public Health Message. Apparently, those public health advocates at the AHA seem to think that changing public health messages—even when they are wrong—confuses widdle ol’ Americans. The AHA—and the USDA/HHS team—doesn’t want us to have to worry our pretty little heads about all that crazy scientifical stuff with big scary words and no funny pictures or halftime shows.

Frankly, I appreciate that. I hate to have my pretty little head worried. But there’s one other problem with this particular Consistent Public Health Message. Not only is there no science to back it up; not only is it likely to be downright detrimental to the health of certain groups of people; not only is it likely to introduce an arsenal of synthetic chemical salt-replacements that will be consumed at unprecedented levels without testing for negative interactions or toxicities (remember how well that worked out when we replaced saturated fat with partially-hydrogenated vegetable oils?)—it is, apparently, incompatible with eating food.

Researchers set out to find what would really happen if Americans were muddle-headed and sheep-like enough to actually try to reduce their sodium intake to 1500 mg/day. They discovered that, “the 2010 Dietary Guidelines for sodium were incompatible with potassium guidelines and with nutritionally adequate diets, even after reducing the sodium content of all US foods by 10%.”  Way to go, Guidelines

While these researchers suggested that a feasibility study (this is a scientifical term for “reality check”) should precede the issuing of dietary guidelines to the public, I have a different suggestion.

How about we just stop with the whole 30-year-long dietary experiment to prevent chronic disease by telling Americans what not to eat? I hate to be the one to point this out, but it doesn’t seem to be working out all that well.  It’s hard to keep assuming that the AHA and the USDA/HHS mean well when, if you look at it for what it is, they are willing to continue to jeopardize the health of Americans just so they don’t have to admit that they might have been wrong about a few things.  I suppose if a Consistent Public Health Message means anything, it means never having to say you’re sorry for 30 years-worth of lousy dietary advice.

Marion Nestle has noted that, up until now, “every single committee that has dealt with this question [of sodium-reduction] says, ‘We really need to lower the sodium in the food supply.’ Now either every single committee that has ever dealt with this issue is delusional, which I find hard to believe—I mean they can’t all be making this up—[or] there must be a clinical or rational basis for the unanimity of these decisions.”

Weeeell, I got some bad news for you, Marion. Believe it. They have been delusional. They are making this up. And no, apparently there is no clinical or rational basis for the unanimity of these decisions.

But, thanks to the IOM report, perhaps we can no longer consider these decisions to be unanimous.

Praise the lard and pass the salt.

Read ’em and weep:  The Reader’s Digest Condensed Version of the science from the IOM report.  Studies marked with an asterix (*) are studies that were available to the 2010 Dietary Guidelines Advisory Committee.  

Studies that looked at Cardiovascular Disease, Stroke, and Mortality

*Cohen et al. (2006)

When intakes of sodium less than 2300 mg per day were compared to intakes greater than 2300 mg per day, the “lower sodium intake was statistically significantly associated with increased risk of all-cause mortality.”

*Cohen et al. (2008)

When a fully-adjusted (for confounders) model was used, “there was a statistically significant higher risk of CVD mortality with the lowest vs. the highest quartile of sodium intake.”

Gardener et al. (2012)

Risk of stroke was positively related to sodium intake when comparing the highest levels of intake to the lowest levels of intake. There was no statistically significant increase in risk for those consuming between 1500 and 4000 mg of sodium per day.

*Larsson et al. (2008)

“The analyses found no significant association between dietary sodium intake and risk of any stroke subtype.”

*Nagata et al. (2004)

“Among men, a 2.3-fold increased risk of stroke mortality was associated with the highest tertile of sodium intake.” That sounds bad, but the average sodium intake in the high-risk group was 6613 mg per day. The lowest risk group had an average intake of 4070 mg per day. “Thus, the average sodium intake in the US would be within the lowest tertile of this study.”

Stolarz-Skrzypek at al. (2011)

“Overall, the authors found that lower sodium intake was associated with higher CVD mortality.”

Takachi et al. (2010)

The authors found “a significant positive association between sodium consumption at the highest compared to the lowest quintile and risk of stroke.” As with the Nagata (2004) study, this sounds bad, but the average sodium intake in the high-risk group was 6844 mg per day. The lowest risk group had an average intake of 3084 mg per day. “Thus, the average sodium intake in the US would be close to the lowest quintile of this study.”

*Umesawa et al. (2008)

“The authors found an association between greater dietary sodium intake and greater mortality from total stroke, ischemic stroke, and total CVD.” However, as with the Nagata and the Takchi studies (above), lower quintiles—in this case, quintiles one and two—would be comparable to average US intake.

Yang et al. (2011)

Higher usual sodium intake was found to be associated with all-cause mortality, but not cardiovascular disease mortality or ischemic heart disease mortality. “However, the finding that correction for regression dilution increased the effect on all-cause mortality, but not on CVD mortality, is inconsistent with the theoretical causal pathway.”  In other words, high sodium intake might be bad for health, but not because it raises blood pressure and leads to heart disease.

Studies in Populations 51 Years of Age or Older

*Geleijnse et al. (2007)

“This study found no significant difference between urinary sodium level and risk of CVD mortality or all-cause mortality.” Relative risk was lowest in the medium intake group, with an average estimated intake of 2, 415 mg/day.

Other

“Five of the nine reported studies in the general population listed above also analyzed the data on health outcomes by age and found no interaction (Cohen et al., 2006, 2008; Cook et al., 2007; Gardener et al., 2012; Yang et al., 2011).”

Studies in Populations with Chronic Kidney Disease

Dong et al. (2010)

“The authors found that the lowest sodium intake was associated with increased mortality risk.”

Heerspink et al. (2012)

“Results from this study suggest that ARBs were more effective at decreasing CKD progression and CVD when sodium intake was in the lowest tertile” which had an estimated average sodium intake of about 2783 mg/day.

Studies on Populations with Cardiovascular Disease

Costa et al. (2012)

“Dietary sodium intake was estimated from a 62-itemvalidated FFQ. . . . Significant correlations were found between sodium intake and percentage of fat and calories in daily intake. . . . Overall, for the first 30 days and up to 4 years afterward, total mortality was significantly associated with high sodium intake.”

Kono et al. (2011)

“Cumulative risk analysis found that a salt intake of greater than the median of 4,000 mg of sodium) was associated with higher stroke recurrence rate. Univariate analysis of lifestyle management also found that poor lifestyle, defined by both high salt intake and low physical activity, was significantly associated with stroke recurrence.

O’Donnell et al. (2011)

“For the composite outcome, multivariate analysis found a U-shaped relationship between 24-hour urine sodium and the composite outcome of CVD death, MI, stroke, and hospitalization for CHF.” In other words, both higher (>7,000 mg per day estimated intake) and lower (<2,990 mg per day estimated intake) intakes of sodium were associated with increased risk of heart disease and mortality.

Studies on Populations with Prehypertension

*Cook et al. (2007)

In a randomized trial comparing a low sodium intervention with usual intake, lower sodium intake did not significantly decrease risk of mortality or heart disease events.

*Cook et al. (2009)

No significant increase in risk of adverse cardiovascular outcomes was associated with increased sodium excretions levels.

Other

“Several other studies discussed in this chapter analyzed data on health outcomes by blood pressure and found no statistical interactions (Cohen et al., 2006, 2008; Gardener et al., 2012; O’Donnell et al., 2011; Yang et al., 2011).”

Studies on Populations with Diabetes

Ekinci et al. (2011)

Higher sodium intakes were associated with decreased risk of all-cause mortality and heart disease mortality.

Tikellis et al. (2013)

“Adjusted multivariate regression analysis found urinary sodium excretion was associated with incident CVD, with increased risk at both the highest [> 4,401 mg/day] and lowest [<2,346 mg/day] urine sodium excretion levels. When analyzed as independent outcomes, no significant associations were found between urinary sodium excretion and new CVD or stroke after adjustment for other risk factors.”

Other

“Two other studies discussed in this chapter analyzed the data on health outcomes by diabetes prevalence and found no interaction (Cohen et al., 2006; O’Donnell et al., 2011).”

Studies in Populations with Congestive Heart Failure

Arcand et al. (2011)

High sodium intake levels (≥2,800 mg per day) were significantly associated with acute decompensated heart failure, all-cause hospitalization, and mortality.

Lennie et al. (2011)

“Results for event-free survival at a urinary sodium of ≥3,000 mg per day varied by the severity of patient symptoms.” In people with less severe symptoms, sodium intake greater than 3,000 mg per day was correlated with a lower disease incidence compared to those with a sodium intake less than 3,000 mg per day. Conversely, people with more severe symptoms who had a sodium intake greater than 3,000 mg per day had a higher disease incidence than those with sodium intakes less than 3,000 mg per day.

Parrinello et al. (2009)

“During the 12 months of follow-up, participants receiving the restricted sodium diet [1840 mg/day] had a greater number of hospital readmissions and higher mortality compared to those on the modestly restricted diet [2760 mg/day].”

*Paterna et al. (2008)

The lower sodium intake group [1840 mg/day] experienced a significantly higher number of hospital readmissions compared to the normal sodium intake group [2760 mg/day].

*Paterna et al. (2009)

A significant association was found between the low sodium intake [1,840 mg per day]) and hospital readmissions. The group with normal sodium diet [2760 mg/day] also had fewer deaths compared to all groups receiving a low-sodium diet combined.

The NaCl Debacle Part 1: Salt makes you fat?

Adele Hite, PhD MPH RD 20 Comments

Don’t look now, but I think the Institute of Medicine’s new report on sodium just bitch-slapped the USDA/HHS 2010 Dietary Guidelines.

In case you have a life outside of the nutritional recommendation roller derby, the IOM recently released a report that comes to the conclusion that restricting sodium intake to 1500 mg/day may increase rather than reduce health risks. Which is a little weird, since the 2010 Dietary Guidelines did a great job of insisting that any American with high blood pressure, all blacks, and every middle-aged and older adult—plus anyone who has ever eaten bacon or even thought about eating bacon, i.e. nearly everybody—should limit their salt intake to 1500 mg of sodium a day, or less than ¾ of a teaspoon of salt. The American Heart Association was, of course, aghast. The AHA thinks EVERYBODY should be limited to less than ¾ teaspoon of salt a day, including people who wouldn’t even think about thinking about bacon.

Why are the AHA and USDA/HHS so freaked out about salt?  And how did the IOM reach such a vastly different conclusion than that promoted by the AHA and the Dietary Guidelines?  Fasten your seat belts folks, it’s gonna be a bumpy blog.

First, it is helpful to examine why the folks at AHA and USDA/HHS are so down on salt.  The truth: we have no freakin’ idea. Salt has been around since what, the dawn of civilization maybe? It is an essential nutrient, and it plays an important role in preserving food and preventing microbial growth (especially on bacon). But Americans could still be getting too much of a good thing. Everybody at the AHA seems to think that Americans consume “excessive amounts” of sodium. (Of course, just about anything looks excessive compared to less than ¾ of a teaspoon.) But do we really consume too much sodium?

Back in 2010, Dr. Laurence I-Know-More-About-Sodium-Than-Your-Kidneys-Do Appel (or as his friends call him, “Low-Sodium Larry”), one of the leading advocates for a salt-free universe, acknowledged that “The data is quite murky. We just don’t have great data on sodium trends over time. I wish that we did. But I can’t tell you if there’s been an increase or decrease.”

Well, Low-Sodium Larry, I can, and I am about to make your wish come true.

According to recent research done by that wild bunch of scientific renegades at Harvard, in the past 60 years sodium intake levels have . . .drumroll, please . . .  not done much of anything.

Hey, that doesn’t sound right! Everyone knows that it is virtually impossible to get an accurate measure of sodium intake from dietary questionnaires; people are probably just “under-reporting” their salt intake like they “under-report” everything else. Low-Sodium Larry has previously insisted that one of the reasons the data is so murky is that few epidemiological studies measure sodium intake accurately and that, “really, you should do 24-hour urinary sodium excretions to do it right.”

The guys at Harvard looked at studies that did it right.  This systematic analysis of 38 studies from the 1950s to the present, found that 24-hour urinary sodium excretion (the “gold” standard—omg, I could not resist that—of dietary sodium intake estimation) has neither increased nor decreased, but has remained essential stable over time. Despite the fact that Americans are apparently hoovering up salt like Kim Kardashian hoovers up French fries—and with much the same results, i.e. puffing up like a Macy’s Thanksgiving Day balloon—for whatever reason we simply aren’t excreting more of it in our urine.

According to that same study however, despite the lack of increase in sodium excretion (which is supposed to accurately reflect intake—but that can’t be right), high blood pressure rates in the population have been increasing. Duh. Everyone knows that eating lots of salt makes your blood pressure go up. But have the rates of high blood pressure in America really been going up?

Age-Adjusted Prevalence of Hypertension (2009 NIH Chart Book)

Well, no.  Not really. The Harvard dudes cite a report that goes back to 1988-1994 data, and yes, rates of high blood pressure have been creeping slowly back up since then. This is because from 1976-1980 to 1988-1994, rates of high blood pressure plummeted for most segments of the American population.

We don’t know why rates of high blood pressure fell during the 70s and early 80s. It may have been that the Dietary Guidelines told people to eat more potassium-filled veggies and people actually tried to follow the Dietary Guidelines, which would have had a positive effect on high blood pressure. On the other hand, it could have been largely due to the sedating influence of the soft rock music of that era blanketing the airwaves with the mellow tones of England Dan and John Ford Coley, Christopher Cross, Ambrosia, and the like (youtube it, you young whippersnappers out there). We also don’t know why rates are going back up. Rising rates of obesity may be part of the problem, but it is also entirely possible that piping the Monsters of Lite Rock through every PA system in the country might save our health care system a lot of time and trouble.

This is what we (think we) know:

  • High-sodium diets might possibly maybe sometimes be a contributor to high blood pressure.
  • Rates of high blood pressure are going (back) up.
  • Obesity rates are definitely going up.

Ergo pro facto summa cum laude, it is clear—using the logic that seems to undergird the vast majority of our public health nutrition recommendations—salt makes you fat.  The USDA/HHS has been faced with rapidly rising rates of obesity which, until now, they have only been to pin on the laziness and gluttony of Americans.  But if salt makes us fat, that might explain why the USDA/HHS doesn’t want us to eat it.

After all, the biomechanics of this is pretty straightforward. If you eat too much sodium (which we must be), but you don’t pee it out (which we aren’t), you must be retaining it and this is what makes your blood pressure and your weight both go way up. They didn’t really cover the physics of this in my biochemistry classes so you’ll have to ask Dr. Appel how this works because he knows more about sodium than your kidneys do. But I think it must be true. After all, this is the mechanism that explains the weight loss behind carbohydrate-reduced diets, right? I myself reduced my carb intake and lost 60 pounds of water weight!

And besides, taking the salt out of our food will give food manufacturers the opportunity to make food more expensive and tasteless while adding synthetic ingredients whose long-term effects are unknown—just what the American consumer wants!

For a while there, we thought the whole idea was to reduce sodium in order to reduce blood pressure in order to reduce diseases of the circulatory system, like heart failure, stroke, and coronary heart disease . That didn’t seem to work out so well, because the whole time that sodium intake was staying stable (if we want to believe the urinary sodium excretion data) and high blood pressure rates were going down (although they are starting to go back up), rates of those diseases have gone up:

Age-Adjusted Prevalence of Heart Failure (2009 NIH Chart Book)

Age-Adjusted Prevalence of Stroke (2009 NIH Chart Book)

Age-Adjusted Prevalence of Coronary Heart Disease (2007 NIH Chart Book)

So if reducing blood pressure to reduce cardiovascular disease isn’t the answer, then we must need to reduce blood pressure to reduce obesity! By jove, I think we’ve got it!

The USDA/HHS must have known the “salt makes you fat” notion would be a tough sell, I mean, what with the lack of any shred of supporting science and all that. (But then, the “salt causes high blood pressure which causes cardiovascular disease” argument hasn’t exactly been overburdened by evidence either, and that never seemed to stop anyone.) So the 2010 Dietary Guidelines brought together the American Heart Association’s Superheroes of Sodium Slashing, Low-Sodium Larry and his bodacious salt-subduing sidekick, Linda Van Horn, both of whom had been preaching the gospel of sodium-reduction as a preventive health measure with little conclusive evidence to support their recommendations.  The USDA/HHS knew that with Linda and Larry on the team, it didn’t matter how lame the science, how limited the data, or how ludicrous the recommendation, these two could be counted on to review any and all available evidence and reliably come up with the exact same concrete and well-proven assumptions they’d been coming up with for years.

The Sodium-Slashing Superheroes–Drs. Lawrence Appel and Linda Van Horn– ready to make the world safe for bland, unappetizing food everywhere! (Drawings courtesy of Butcher Billy)

So here’s the cliffhanger:  Will Linda and Larry be able to torture the science on salt into confessing its true role in the obesity crisis?

Tune in tomorrow, when you’ll hear Linda and Larry say: “Science? We don’t need no stinkin’ science.”

Americans don’t follow Guidelines—or do they?

Adele Hite, PhD MPH RD 2 Comments

One of the enduring myths of our current nutrition culture is that Americans don’t follow recommendations–have never followed them–because if we had, this obesity thing wouldn’t have happened. According to the 2010 Dietary Guidelines Advisory Committee Report, “average American food patterns currently bear little resemblance to the diet recommended in the 2005 Dietary Guidelines for Americans.”

As proof, the following figure is provided:

FIGURE 1: Americans don’t follow dietary recommendations!

It seems pretty obvious that Americans are woefully off-base when it comes to eating anything close to what the USDA and HHS have been recommending for the past thirty years. I would bet my RD certification that this figure will be shown in PowerPoints across the land to demonstrate—to the accompaniment of much hand-wringing—how we must “make the healthy choice the easy choice” for those poor, dumb Americans who will otherwise just eat themselves into obesity and ruin airplane trips for the rest of us.

Aside from the fact that Americans are being evaluated on whether or not they follow the Guidelines, rather than whether or not the Guidelines are actually appropriate, there are some serious “truth in advertising” issues going on with this figure.

First, note the data collection time points: National Health and Nutrition Examination Surveys from 2001-2004, and 2005-2006. And the fun begins . . .

1) The figure shows that we eat too many calories from SoFAS. But this concept was not part of the Guidelines until the 2010 Dietary Report, the report that contains this figure. In other words, Americans are being held to standards that hadn’t even been created yet.

2) The saturated fat “cut-off” is based on a 7% of calories. The recommended limit for saturated fat at the time the data were collected and at the time this document was written is 10% of calories, not 7%.

3) The standards for whole grain consumption given in the Guidelines that the public would be familiar with when the data were collected were pretty vague: “Choose a variety of grains daily, especially whole grains” (from the 2000 Dietary Guidelines). I don’t know how this translates into an absolute amount of whole grains that Americans don’t consume.

4) The report that contains this figure (the 2010 Dietary Guidelines Advisory Committee Report) indicates that added sugars should be less than 25% of calories. Current research indicates that added sugar consumption by Americans is around 16% of total calories (Welsh et al, 2010, JAMA). According to this figure, Americans consume 242% more added sugars than recommended. Another mystery.

5) In the fine print, it says that the sodium cut-off is based on the recommended Adequate Intake (AI) amount. The AI amount is a “goal for adequate intake,” and, as such, is more of a floor than a ceiling. The AI amount is currently set at 1500 mg of sodium for adults. On the other hand, the Dietary Guidelines that were in effect at the time the data were collected set sodium recommendations at 2400 mg (2000 DGs) and 2300 mg (2005 DGs) per day.

Americans don’t follow the Guidelines–but the standards being used in a number of cases aren’t even part of the Guidelines?

Here’s a different perspective on whether or not Americans are following dietary recommendations:

FIGURE 2: Or do they? Black lines represent lower limits of Acceptable Macronutrient Distribution Range (AMDR) given in the Dietary Guidelines; red lines designate upper limits of AMDR.

Since 1980, Americans have been told to increase their carbohydrate consumption and reduce their fat intake. Since 1980, we’ve done just that. American’s consumption patterns fall within the recommended AMDR levels, with the exception of saturated fat, which—at 11% of total calories—is just slightly more than the recommended limit of 10% of calories. (If you are interested in just exactly how well Americans have complied with the dietary recommendations of the past 30 years, you can find the gory details here.)  Far from being careless and casual consumers of anything and everything, Americans have radically shifted their eating patterns to match recommendations.

So why don’t Americans get any credit for actually lowering their fat intake and raising their carbohydrate intake, as we were told to do? I think there are a couple of things behind that.

First, I think one of the purposes of information like that presented in Figure 1 is to make sure the responsibility for overweight and obesity continues to rest squarely on the chubby little shoulders of Americans themselves and in no way reflects a possible lack of appropriateness of (or—gasp!—good scientific basis for) the Guidelines themselves. This is an attitude that pervades the Dietary Guidelines.

Second, the USDA’s Center for Nutrition Policy and Promotion would really like another $9 million to “help Americans develop eating behaviors that are more consistent with the Dietary Guidelines for Americans.” It would be a little awkward to ask for a funding increase to convince Americans to follow current dietary recommendations if we were already doing that—and they still weren’t working.

This is where recommendations become fanaticism.  According to Neil Postman, “the key to all fanatical beliefs is that they are self-confirming.”  The USDA and HHS seem unwilling to even acknowledge that the dietary shift that has occurred during the past thirty years has actually been in the direction of compliance with recommendations; in fact–according to Figure 1–they are willing to fudge the numbers to prove otherwise.  That’s not nice, and it’s sure not science.

References:

Welsh JA, Sharma A, Abramson JL, Vaccarino V, Gillespie C, Vos MB. Caloric sweetener consumption and dyslipidemia among US adults. JAMA. 2010 Apr 21;303(15):1490-7