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
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.
Historically, aldosterone was considered a hormone released from the adrenal cortex in response to low salt intakes. It was thought to exert its effects solely through mineralocorticoid receptors, thereby causing sodium retention and potassium loss. More recently, however, a much wider role for aldosterone has been recognized.
Research efforts have revealed a host of new pathophysiologic mechanisms associated with elevated aldosterone that could be expected to contribute to the progression of congestive heart failure and sudden cardiovascular death.
More importantly, the recent evidence is based upon research into the actual metabolic mechanisms rather than epidemiological or observational studies, which are generally open to a range of mechanistic interpretations and confounding errors. A growing body of evidence suggests that . The endothelium is the thin layer of cells that line the interior surface of all blood vessels. It serves as the interface between the circulating blood and the rest of the vessel wall. The condition of the endothelium plays a critical role in the regulation of vascular tone, platelet aggregation within the vessel, the adhesion of leukocytes and overall blood coagulation. When the endothelium is not right, as in endothelial dysfunction, it is predictive of future cardiovascular events.
Because low salt diets stimulate elevated aldosterone levels, this phenomenon may very well explain the repeated findings that more people on low salt diets succumb to cardiovascular disease than those on normal or high salt diets, which we reported on previously.
In the past, experimental studies have focused on the pathological effects of angiotensin II, rather than aldosterone, and demonstrated that angiotensin-converting enzyme inhibitors confer significant cardiovascular protection. However, more recently, research has revolutionized our view of aldosterone and its biological actions, and identified mineralocorticoids as important mediators of cardiovascular injury. Elevated aldosterone levels can cause cardiovascular injury without raising the blood pressure, and aldosterone blockers can exert significant protective effects without lowering the blood pressure.
Infants born with a low birth weights tend to have higher aldosterone levels when they are older. This corresponds to recent research, which we previously reported on demonstrating that low birth weight babies are also born with low sodium in their blood serum because their mothers were on low salt intakes.
The current evidence concludes that that a long-term increase in aldosterone production from early on in life is determined by an interaction of genetic and environmental factors, such as diets that are low in salt. This leads to cardiovascular damage in middle age and beyond. These results have been confirmed by at least two other studies, one from Israel and one from Japan, which further state that the current upper limit of 2300 mg sodium per day (6 g of salt), described in the Institute of Medicine Dietary Reference Intakes is insufficient to prevent the triggering of elevated aldosterone levels.
As more and more high quality evidence mounts on the malignant impact of elevated aldosterone levels upon cardiovascular function, it is hoped that the voice of the medical establishment and the new Dietary Guidelines on sodium will take this squarely into account.
As the title suggests, "Aphrodite, sex and salt ," an article just published in the July issue of Nephrology Dialysis Transplantation is wide ranging in its medical and cultural purview.
The article describes "major effects on procreation, gestation and lactation" when humans reduce dietary salt intakes. Bernard Moinier, former staff executive of the European salt association and the French salt association, teamed with Dr. Tilman Drueke to explore neurophysiological mechanisms linking reproductive functions with salt appetite and hormone generation and conclude "a sodium replete state (is strongly related) to fertility and reproductive performance." Of particular note, they point out the hormonal changes that occur related to salt intake during pregnancy and remind us of "a reasonable degree of agreement that salt intake should not be reduced during pregnancy." This is an especially important finding because expectant mothers are the most important target for advice to use iodized salt.
Back in 2003, the Cochrane Collaboration published its evidence-based review of the health outcomes of reducing dietary salt, concluding:
Intensive interventions, unsuited to primary care or population prevention programmes, provide only minimal reductions in blood pressure during long-term trials. Further evaluations to assess effects on morbidity and mortality outcomes are needed for populations as a whole and for patients with elevated blood pressure.
Coming from the inventors of the term "evidence-based medicine," this should have caused reconsideration of the entire approach of universal salt reduction. It also pointed the way to resolving the ongoing conflict among medical experts about whether salt restriction should be part of recommended dietary guidelines: it called for "further evaluations to assess effects on morbidity and mortality outcomes...."
Since then, several new studies have been published on the health outcomes of low-salt diets; they haven't confirmed a benefit.
So the Cochrane Collaboration has re-issued its 2003 Review, unchanged .
Proponents of evidence-based nutrition recommendations should use the 2008 version to counter the statistically-creative, substantively-deficient, blood pressure-centric arguments posited by proponents of the status quo. As this re-publication reminds us, it's time to sweep away opinion-based recommendations and replace them with sceince-based guidelines.
We have all sorts of animal studies trying to discover mechanisms of human physical and psychological function. Rat studies, dog studies. But...worm studies?
Researchers at the University of Oregon have discovered that woms perform a calculus based on their sensing of salt to determine whether to proceed straight ahead (high salt) or stop and consider other options. If this were the Calaveras County (CA) jumping frog race, we'd put our money on the high-salt roundworm.
Read about it in the July 3 edition of Nature as reported in advance by Physorg.com from which was gleaned this explanatory graphic. A spike in salt concentration in ASEL (left neuron) activates expression that leads a worm to proceed in a straight line. A dip in salt levels in ASER (right neuron) turns on a negative reaction that tells a worm to change to a turning movement to look around. Graphic courtesy of Shawn Lockery.
Using as examples the role of salt in combatting lymphatic filariasis and iodine deficiency, the cover story of the June issue of Geotimes devoted six pages to "Salt of the Earth: the pubilc health community employs a mineral to fight infectious disease ." Pointing out that its economy and ubiquity make salt the "ideal vehicle" to fortify with minerals or medications, author Cassandra Willyard concludes: "The saltshaker has become one of the most powerful weapons in the public health arsenal."
The article recounts the pioneering public health efforts to combat iodine deficiency by iodizing salt, quoting Venkatesh Mannar, executive director of the Ottawa-based Micronutrient Intitiative, explaining that salt is the "food that comes closest to being universally consumed." Salt is preferred because "the risk of overdose is minimal because everyone eats a predictable amount."
Building on the success of salt iodization, salt was fortified with other additives, first fluoride to prevent dental caries and then chloroquine to prevent malaria and most recently DEC (diethylcarbamazine) to combat lymphatic filariasis. Willyard featured the World Health Organization's ongoing work with DEC-fortified salt in Haiti and Guyana.
The article also broaches the question of the adequacy of iodine nutrition in the U.S. where substitution of processed foods using plain salt for home-cooked meals using iodized salt has led to a gradual decline in iodine intake levels. Willyard includes the Salt Institute's views, noting "officials may think about adding iodized salt to processed foods, Hanneman says. The important things, he adds, is to keep monitoring."
Choose a few minutes when you want a pick-me-up -- and bookmark the URL for future reference; you'll want to read a new Junk Food Science blog post "Traffic tickets for salt -- does healthy eating mean low salt? "
In a word, "no." But here is author Sandy Szwarc's lead to give you the flavor:
Salt makes food taste good. Therefore, it must be bad for us. Enjoying food means people might eat too much and get fat.
Believe it or not, that is the logic behind beliefs that everyone - from children to adults - should reduce their salt intake as an important part of 'healthy' eating.
Fears of salt have become so widespread, even little kids are being told it's bad for them and given low-salt diets.
She quickly moves to explain why this matters:
But salt is another food ingredient where the science and the voices of medical experts have had a hard time breaking through myths, fears and pop ideologies.
What may seem inconceivable, given the Red Lights being given to salt, is that there is no credible evidence low-salt diets can help prevent heart disease, high blood pressure or premature death. Nor is there any sound evidence to support fears that we're eating too much salt and that high salt diets increase our risks for cardiovascular disease and deaths. Nor can we assume that putting everyone on low-salt diets "can't hurt" and are benign. In fact, the medical research suggests the very opposite.
She continues at length (more than 2,250 words) to explain the NHANES research results from the Albert Einstein Medical College as well as the just-reissued Cochrane Review on "Advice to reduce dietary sodium for prevention of cardiovascular disease." The advice, of course, is: don't bother; there's no evidence of a a heath benefit.
Significantly, Szwarc recounts the multiple risks for those who follow political convention and curtail their salt. Our short post cannot do it justice. You need to read it yourself.
She concludes with this warning:
There are a lot of urban legends about salt, from "salt kills" to "cutting salt can add years to your life." The scariest thing isn't salt, though. It's that scare-based legends and myths, rather than good science, are guiding public health policies, the "nutrition" education being given children, and the public health messages teaching everyone to fear salt. Agendas that are not about health.
We can see why the blog was a finalist for the best new medical blog. Happy reading.
Scotland's youth just received their health "report card " from the World Health Organization. The report was prepared by a Scottish doctor for WHO-Europe and represents rosy health results for Scottish youngsters (among others).
It presents the key findings on patterns of health among young people aged 11, 13 and 15 years in 41 countries and regions across the WHO European Region and North America in 2005/2006. Its theme is health inequalities: quantifying the gender, age, geographic and socioeconomic dimensions of health differentials. Its aim is to highlight where these inequalities exist, to inform and influence policy and practice and to help improve health for all young people.
The report clearly shows that, while the health and well-being of many young people give cause for celebration, sizeable minorities are experiencing real and worrying problems related to overweight and obesity, self-esteem, life satisfaction, substance misuse and bullying. The report provides reliable data that health systems in Member States can use to support and encourage sectors such as education, social inclusion and housing, to achieve their primary goals and, in so doing, benefit young people's health. Policy-makers and professionals in the participating countries should listen closely to the voices of their young people and ensure that these drive their efforts to put in place the circumstances - social, economic, health and educational - within which young people can thrive and prosper.
Yet, within a week, a local paper reported that the government's crusade to re-make Scots' diets will be accelerated. If the kids' "report card" was okay, clearly their parents need some shaping up. Among the new initiatives:
Ministers also want to change the way cooking is taught in the nation's catering colleges by getting young chefs to rely less on salt, sugar, butter and cream, and more on healthy alternatives.
Among the interventions planned is having every worker log in daily using government software to report to the government on his or her personal diet and health situation. The Confederation of British Industry objected.
Iain McMillan, the director of CBI Scotland, said: "I think we will want to look at the detail and we are in favour of promoting health. But it seems that some people are drinking far too much and some are eating far too much and it's everyone else's fault but their own. We need to have far greater regard for the fact that people are responsible for their own welfare. And this seems to be a very heavy-handed approach."
Regular readers will recall the earlier attempt in Glasgow to "lock down" schools at lunch time because students were going off-campus to avoid the "healthy" fare in their cafeterias -- and monitors were to check students' brown bag lunches for nutritional adequacy.
And this from the nation that gave the world the Magna Carta.
Our thanks to Junk Food Science for surfacing the issue.
