The New England Journal of Medicine recently published a long-term follow-up study to determine the impact of tight control over blood pressure among patients with Type II Diabetes. Researchers at the United Kingdom Prospective Diabetes Study (UKPDS) wanted to see whether the risk reductions achieved during periods of tight control over blood pressure would be sustainable after those controls were relaxed.
Out of 5000 patients with newly diagnosed type II diabetes, they randomly assigned more than 1000 that had hypertension to either tight or more relaxed blood-pressure control regimes. Patients with blood pressures greater than or equal to 160/90 mm Hg were randomly allocated to tight-control, aiming for less than 150/85 mm Hg with either an angiotensin-converting enzyme inhibitor or a Beta-blocker or to less-tight-control aiming for less than 200/105 mm Hg. Patients who underwent post-trial monitoring were asked to attend annual UKPDS clinics for the first 5 years, but no attempt was made to maintain their previously assigned therapies.
What was the result? After the trial, blood-pressure levels fell in the less-tight-control group and rose in the tight-control group, with no significant differences between the groups after 2 years. In line with this equalization of blood pressures, there were no significant risk reductions observed between the groups 10 years after the trial.
Differences in blood pressure between the two groups during the trial disappeared within 2 years after termination of the trial. Significant relative risk reductions found during the trial for any diabetes-related end point, diabetes-related death, microvascular disease, and stroke in the group receiving tight, as compared with less tight, blood-pressure control were not sustained during the post-trial follow-up.
For more than a quarter of a century, the Department of Health and Human Services and the Department of Agriculture have jointly published a new version of the "Dietary Guidelines for Americans" every five years. In 2010, the sixth edition of this publication will come out.
With reference to the consumption of salt, the Dietary Guidelines has served the public poorly. The fact of the matter is that the figures are based entirely upon expert opinion, not scientific trials. This was confirmed in the paper delivered at the Institute of Medicine workshop "The Development of DRIs 1994-2004: Lessons Learned and New Challenges" held in Washington September 18-20, 2007 by Dr. Peter Greenwald, Director of Cancer Prevention at the National Cancer Institute of the National Institutes of Health . Dr Greenwald described how most of the figures behind the recommended dietary intakes were based upon expert opinion - the lowest quality of medical evidence - rather than randomized controlled double blind clinical trials - the highest level of evidence.
The next iteration of the Dietary Guidelines will be the sixth in the series. Are we destined to continue basing our dietary recommendations on the lowest level of evidence? What would happen if Americans actually adhered to the dietary guidelines? The only evidence we have thus far is not particularly reassuring. In two studies on healthy young adults, carried out in very different geographic locations, college students were limited to 2300 mg Na/day - the Upper Limit for sodium recommended by the Institute of Medicine (1), (2). In both cases, all the students taking part in the trial experienced elevated aldosterone levels, and in the case of the Shapiro et al. study, they all showed evidence of arterial stiffness.
These are the only experimental results we have relating to the Institute of Medicine recommendations for sodium intake. Surely, it behooves us to test whether the IOM's recommendations are safe for Americans or not. If they once more appeared in the Dietary Guidelines, based solely on expert opinion, consumers would be justifiably bound to abandon confidence in the science behind these recommendations.
It is time to step up to the plate and have the Institute of Medicine recommendations tested experimentally
We need to establish a trial with a significant group of healthy young adults who are comprehensively counseled on how to limit their sodium intake to 2300 mg/day. As a lead-in to the trial, their baseline blood pressures, 24-hr urinary sodium, and plasma renin and aldosterone levels would be accurately determined. Once the trial began and the young adults maintained their sodium intakes at 2300 mg/day, these parameters will be checked on a weekly basis. The trial will continue for 30 days and a final analyses of blood pressures, urinary sodium, renin and aldosterone would be taken.
Such a trial would give us an excellent understanding of the impact of maintaining a consumption level of 2300 mg/day of sodium or less - on blood pressure as well as renin/aldosterone levels. It would be the first large-scale trial into the effect of adhering to the IOM recommendation for sodium and will be critically important in establishing the next edition of the Dietary Guidelines. Such a trial would not be overly costly and would, for once, remove considerable doubt regarding the validity of the IOM recommendations.
(1) Kodama N, Nishimuta M, Suzuki K., "Negative balance of calcium and magnesium under relatively low sodium intake in humans," J Nutr Sci Vitaminol (Tokyo), 2003, Jun;49(3):201-9.
(2) Shapiro, Y., Boaz, M., Matas, Z., Fux, A., & M. Shargorodsky, "The association between the renin-angiotensin-aldosterone system and arterial stiffness in young healthy subjects," Clinical Endocrinolog,. 2008 Apr;68(4):510-2.
Score one for the good guys! The European Food Safety Authority (EFSA) recently adopted the rationale proffered by EuSalt and announced it would forego multi-national dietary guidelines. EFSA announced :
The main conclusion of the Panel is that it is not feasible to establish detailed and effective FBDG [note: Food Based Dietary Guidelines] which could be used at the EU level as diet-related public health priorities may differ between countries. FBDG must also take into account wide disparities in dietary habits, due to cultural differences in eating patterns and the varying availability of food products across Europe. Therefore the NDA Panel decided to focus its opinion on the scientific process underlying the development of FBDG.
EuSalt hailed the decision as "evidence for its long-standing position, namely that it is not feasible to generalise, neither globally nor on European level, requirements on the intake of salt." EuSalt argued broad guidelines would "be dangerous for many." EuSalt also expressed pleasure at the newly-announced review of the scientific process underlying dietary advisories.
The Salt Institute congratulates both EFSA and EuSalt for their enlightened advocacy.
Arguing hyperbolically that it is "even more important to reduce consumption of sodium" than to eliminate trans-fat in foods, two staffers at the New York City Department of Health and Mental Hygiene editorialized in this week's Journal of the American Medical Association (JAMA , subscription required) that "it is nearly impossible for consumers to greatly reduce their own salt intake." They urge drastic government controls to "protect the public from unhealthy food" such as restrictions on marketing foods they don't like and subsidizing the consumption of government-favored foods, zoning restrictions to bar location of restraurants that serve foods they don't like or taxes on such "bad foods."
In short, the solution is to restrict consumer choices to their know-it-all choices. "The modern food supply is tainted -- it is too salty, too sugary, and too rich in calories, and there is simply too much of such food easily available," they continue, arguing that governments should regulate the amount of salt and added sugar in foods. "Food safety for the 21st century should be reframed....public health systems must reduce the contribution of food to the epidemics of obesity and chronic disease."
Over the past year, with evidence turing against arguments for universal sodium reduction, advocates of cutting salt are becoming shriller and more totalitarian. Perhaps the the NYC Department of Health is upset that reason Magazine ranked New York City the nation's second-worst "nanny-state city" (behind San Francisco) when it comes to dietary fascism and the Big Apple is out to regain its #1 ranking.
A new analysis released today by the U.S. Department of Agriculture reported fewer Americans using federally-mandated nutrition information, especially sodium. The 2005-2006 NHANES study of 9,416 representative consumers found about 7 in 10 use the Nutrition Facts label, about the same as a decade ago. For sodium, only 66% consulted the label in 1995-1996 and that number declined 10% to 60% in 2005-2006. Among nutrients, only cholesterol fell more, 11%. Among all the listed nutrients, fiber was the only one where consumers registered increased concern as reflected in label use.
The label was mandated in 1994; sodium labeling had been in effect a decade before that.
Over the past ten years, 5% more reported "never" using the label. For salt/sodium, the increase in "never use" increased by 10 points from 12% to 22%. A decade earlier, 36% "always/often" used the sodium label; that eroded to 34%.
It would take another study to tell us why consumers are shunning nutrition information, but the pattern is consistent. Eleven percent fewer are using label health claims (37% "never") and even the ingredient list (32% "never"). With the multiplicity of advisories and the fact that scientists dispute the health consequences of cholesterol and sodium (and other nutrients), consumers are overwhelmed and doubtful about the advice they're being given. That's why the new Dietary Guidelines should adopt an "evidence-based medicine" approach in lieu of the expert panel approach of past reviews.
Many consumers continue in ignorance about the primary reason for consuming iodized salt: fetal and infant brain development. This isn't an aesthetic issue. For example, as my comment to this blogger notes, iodine deficiency for an expectant mother can penalize her child 10-15 IQ points.
The general public understands that blood pressure is an important risk factor for cardiovascular health. Most people don't realize that the hormone aldosterone is an even more powerful risk factor predicting cardiovascular events and mortality. After reading the latest issue of the just-released Salt and Health newsletter, you will understand that aldosterone is the key to understanding why low-salt diets have not proved beneficial to human health.
The U.S. Department of Agriculture released results of the 2005-2006 NHANES database today. Entitled "What we eat in America," you're probably going to read about it in the MSM. I doubt you'll read in the newspapers what you read here.
This survey of what Americans eat and how it relates to their health and mortality has been conducted for about 35 years. The 9,349 individuals are selected to be a cross-section of American society.
Analyses of earlier NHANES reports (I, II and III) have consistently and convincingly disparaged the notion that those on low-salt diets enjoy any health advantages. See, for example, the analysis of NHANES III on this point presented recently to the annual meeting of the Canadian Society of Clinical Nutrition.
The 2005-2006 data will eventually be combined with health outcomes data allowing this analysis. For now, however, we have the nutrient intake data. The sodium data is on page 4 . Those data unmask another shibboleth employed by crusaders for universal salt reduction, namely that African Americans and Mexican immigrants are particularly prone to consume "excess sodium" putting themselves at a health risk.
The data tell a different tale. Whatever the ultimate health outcomes of these groups, don't blame salt intake. The average American in 2005-2006 consumed 3,436 milligrams of sodium a day -- the same as it's been for a century or more and smack dab in the middle of the global range of population intakes, contrary to anti-salt proselytizers' contention that Americans eat an abnormally high amount of salt.
Compare the average 3,436 mg/day to these groups; what do you find? African Americans ("non-Hispanic blacks" in the government's nomenclature) consumed only 3,257 mg/day. That is 5% less than average and 8% less than Caucasians. For Mexican Americans the difference is greater still; Hispanics eat only 3,162 mg/day of sodium, 8% less than average and more than 10% less than whites.
The Salt Institute has argued that we need to focus more on total quality diet; our opponents have explicitly rejected that policy direction , arguing that sodium/salt reduction would be superior. Let's follow the data. African Americans are the identified priority beneficiaries of salt reduction, its proponents say. Experts have argued that dietary potassium is an excellent indicator of a qualty diet: the higher the potassium, the better the diet. These new USDA data show African Americans eating 14% less potassium than average. The data support our call for an emphasis on overall dietary improvement, not salt reduction.
It's been another bad month for the anti-salt crowd. In early July, other USDA data showed no change in Americans' sodium consumption over the past 40 years, disproving the argument that our increased consumption of processed foods has led to an increase in sodium intake. Not so, said USDA. Then, the study they welcomed as "definitive," actually disproved their contention that salt worsened asthmatic conditions . Pesky data, those.
Dr. Hillel Cohen of the Albert Einstein College of Medicine, NYC and author of several health outcomes studies of the NHANES database, delivered a PowerPoint presentation recently to the Canadian Society of Clinical Nutrition 's annual scientific meeting in Toronto. CSCN has rendered a valuable service by putting the presentation .
The website of WASH (World Action on Salt and Health) states that a double-blind study of modest salt restriction caused a reduction in the severity of asthma attacks and a reduction in the use of medication and an improvement in the measurement of airways resistance. The article concludes with a statement:
"It seems therefore that, while salt is not a direct cause of asthma, a high salt intake can act as a major aggravating factor."
The CASH (Consensus Action on Salt and Health) website similarly states:
Going a step further, another CASH document confidently wrote with great anticipation of the upcoming University of Nottingham study which would once and for all establish the relationship between salt and asthma.
On page 15 of the CSPI (Center for Science in the Public Interest) book, Salt-The Forgotten Killer it states that:
"High-salt diets impair lung function and worsen asthma symptoms"
The NHLBI (National Heart, Lung, and Blood Institute) paper on salt and health, A Critical Review of Current Scientific Evidence indicates in their opening section on sodium intake and non-CVD conditions that:
"Several studies have shown direct associations between sodium intake and other conditions, including ....indicators of asthma."
All four websites claim to be portraying good science, responsible science, all in the public's interest, yet, all four made the relationship between salt and asthma as if there were a solid scientific relationship between the two. Grasping at whatever straws they could to forward their own parochial agendas, they misinformed the public in this matter of health. It will be interesting to see how long it takes for them to retract their statements on the relationship between salt and asthma. It will also be interesting to see if they apologize to their readership for misinforming them.
Today, June 16, 2008, reports started coming in from, among others, CBS , the CBC and The Press Association of the long-anticipated definitive University of Nottingham study to examine the relationship between salt intakes and asthma. The University of Nottingham press release was emblazoned with the title, "Low-sodium advice for asthmatics should be taken with a pinch of salt. " The conclusion of their story stated that the new study by researchers at The University of Nottingham found no evidence that cutting back on salt helps patients with their asthma symptoms.
Once more, we see clear incontrovertible evidence of a patently obvious anti-salt movement that is only too willing to spread myth-information and pseudo-science about an issue, long before the actual science has been definitively established.
As I mentioned above, we will be revisiting the websites of these "scientists" in future to see how quickly they correct their misinformation and apologize for it. This may well show "the measure of the man."
Picking up where Scotland left off , KIng David School in Childwall, Liverpool, UK is considering banning home-packed school lunches.
Junkfood Science blew the whistle on that one, opining: "Imagine being able to make a law eliminating competing products and convince people it's for the children."
Apparently the British mania for food faddism continues. The LIverpool Echo quotes the chairwoman of governors at the school explaining the need to prevent students from consuming low-quality lunches packed by their mothers, explaining "We are amazed at what we find in children's lunch boxes. Some even come in with doughnuts." Can you IMAGINE? Doughnuts in a school lunch? The chair of a local charity, the Child Growth Foundation, joined the chorus: "If parents send in rubbish in lunch boxes, then the school has got to ban them." The "charity" is funded by the UK government.
The cover story of reason magazine's August/September issue ranks America's 35 largest cities with regard to their "nanny-state" proclivities. The rankings include the libertarian rag's judgment on each city's ordinances and community profile in eight areas: sex, tobacco, alcohol, guns, traffic enforcement, drugs, gambling and food/other. Our interest, naturally, is on "food/other." Perhaps unsurprisingly, when it comes to active "food police" atmosphere, San Francisco is America's most-nannying city, followed by New York, Los Angeles and Seattle. At the polar extreme was a six-way tie (listed in reverse order of each city's overall nannying score): Miami (overall #2), Denver (overall #3), Milwaukee, Jacksonville, Atlanta, and Detroit (Las Vegas, the overall #1 slipped to a tie for 7th in politically-correct food enforcement. Here's the list
Least nannying: Miami, Denver, Milwaukee, Jacksonvill, Atlanta, Detroit Tie for 7th place: Las Vegas, Portland, Phoenix, Cleveland, Washington-DC, Columbus, Charlotte Tie for 14th place: Louisville, Ft. Worth, San Antonio, Austin, Dallas, Indianapolis, Houston, El Paso Tie for 22nd place: Kansas City, Memphis, Nashville Tie for 25th place: Baltimore, Philadelphia, Boston 28th place: Chicago Tie for 29th place: Oakland, San Jose San Diego 32nd place: Seattle 33rd place: Los Angeles 34th place: New York City 35th place (worst nanny-state city): San Francisco
A new study in The Journal of Clinical Endocrinology & Metabolism found that "Prolonged iodized salt significantly improves maternal thyroid economy and reduces the risk of maternal thyroid insufficiency during gestation, probably because of a nearly restoring intrathyroidal iodine stores."
Women who used salt for at least two years before becomng pregnant avoided thyroid failure during pregnancy. The Italian research team found in its study of 100 women, 62 of whom were "long-term" users of iodized salt and 38 of whom were not. The short-term group had a six-fold greater incidence on thyroid failure.
In response to a direct question today at a food industry conference in Chicago, Dr. Lawrence Appel who chaired the "objective" Institute of Medicine sodium review and then chaired the 2005 Dietary Guidelines sodium guideline panel, denied he is a member of the anti-salt lobby group, World Action on Salt and Health. Apparently WASH hasn't received his letter of resignation since its website still lists him as member #268 .
Fellow WASH partisan, Michael Jacobson (#189) told the group "we've tried voluntary action (to curtail salt intakes) and it doesn't work." Contrasting the US and UK, he declared that the UK government "is interested in public health" (ergo the US government isn't) and, finally, he allowed that salt reduction is easy, and the UK has made dramatic strides with miniscule resources -- only two full time bureaucrats, he stated.
Other speakers added a modicum of balance. Dr. Connie Diekman of Washington University in St. Louis and immediate past president of the American Dietetic Association explained her group's devotion to an evidence-based approach and refused to pre-judge its ongoing review. Grocery Manufacturers Association Senior Nutrition Policy Director Bob Earl again endorsed the Salt Institute's call for a controlled trial of the health outcomes of salt-reduced diets. He noted that the suggested weekly menu to implement USDA's My Pyramid diet guideline provides 2,900 mg/day sodium. Alana Moshfegh, senior researcher at USDA, characterized her presentation as a "reality show" amongst the anti-salt presenters and said salt usage has grown only 3% since 1980 (even that's an overstatement ; as she spoke, her colleagues in Beltsville, MD were releasing data showing no increase at all).
For our non-US readers, the headline references the latest dust-up in the US presidential race where presumptive Democratic nominee, Chicagoan Barack Obama, announced those who interpreted his post-primary statements as changed positions "haven't apparently been listening to me" and GOP nominee-presumptive John McCain joined the argument.
Mort and I are at a meeting in Chicago this week. Today, the usual anti-salt crowd (Michael Jacobson, Larry Appel, et al) told a food industry conference that they should be concerned that Americans' appetite for salt is greater today than ever before. We've contended there hasn't been much change in a century.
Returning to my hotel room, I found a new database just announced by the US Department of Agriculture's Economic Research Service tracking the nutrient composition of the US diet back nearly 100 years. For perspective, the government's NHANES database figures Americans take in about 3,400 mg/day of dietary sodium.
In this database, " ," USDA analysts estimate that per-capita daily sodium intake has increased 10 milligrams and has had swings of only about +/- 40 milligrams throughout the entire last half century, 1955-2005 (the latest data).
Maybe bit by bit our "truth squad" can get this debate to focus on facts. Everyone's entitled to their opinion; no one is entitled to their own facts.
Just for our readers' information, summarizing some of the changes in other nutrients since 1970, the analysis found in 2005 each American consumed (on average) 80 more pounds of commercially grown vegetables than in 1970, plus 56 more pounds of grain products and 34 more pounds of fruit. On the other hand, the numbers show the average American ate 55 fewer eggs and drank 10 gallons less milk and nine gallons less coffee. Protein intake shifted in favor of poultry (40 more pounds), cheese (20 more pounds), and fish (4 more pounds of boneless, trimmed equivalent), but with a 17-pound drop in red meat. Americans ate 31-pounds more in fat and oil additives and 23-pounds more of sweeteners. Gosh, maybe salt ISN'T the culprit in our "obesity epidemic." The data also track the well-known concern for calcium deficiency, especially in early-teenage girls. The ten gallons/year drop in milk represents 34 milligrams a day less calcium (mineral deficiencies, of course, are a trigger for salt-sensitive changes in blood pressure and a major reason why the Salt Institute has so strongly supported the DASH Diet, high in fruits, vegetables and dairy products.
