Author Taubes strikes again, frees salt from PC jail, to horror of some
A study established the danger of too little salt forty years ago, but doesn’t science support danger of too much?
Albert Schweitzer (and Amazon Indians) point to stark contrast between Native vs Western diet, and its result
The key may be to aim at a potassium/sodium balance 5 to 1 or more
One of the very few science writers who quarrel with the establishment when it walks the plank into a sea of ignorance, expecting us all to follow, is the impressive Gary Taubes, an author who searches the literature himself and is willing to say that even Harvard (his alma mater) can carry out bad research.
He is also one of the few dissenters and critics among journalists who have managed to retain a flourishing career while he does it. Somehow he has managed the trick of rubbing the noses of under researched top dogs (those who fill panels with reassuring waffle, and lead conferences and science journalists by the nose and away from any dissenting research that has been published) in that contradictory literature and not get drawn and quartered for it.
Instead of having his career blighted as sources dry up and received wisdom goons attack him in the New York Times, Taubes won one of the fattest advances ever for his corrective diet book on “Why We Get fat”, gained a perch at the Robert Wood Johnson Foundation as an Independent Investigator in Health Policy, and here he is in the Sunday New York Times Review speaking up for salt, armed with relevant scientific studies, in a reprise of his Science article in 1998, The (Political) Science of Salt.
We think he deserves every dollar he has won with his double checking of the rickety rationales for blaming fat for obesity and now for blaming salt for undermining our cardiac health. As Taubes writes, not only has there been a paucity of convincing studies over the last forty years proving that salt gives you permanently high blood pressure, but there has recently been new evidence confirming the 1972 result that reducing salt might well make you pay with other ills, including increased output of renin from the kidneys which will end in heart disease and earlier death.
Taubes secret – apart from the fact he does copious research – may be that he studied at Harvard (applied physics) and Stanford (aerospace engineering) before attending the journalism school at Columbia, a path which not only made him a fully paid up member of the Establishment or at any rate the Harvard Mafia himself but also must have taught him more about the difference between cause and correlation than your average diet epidemiologist.
This is what he says today, in his latest Op Ed mythbusting this coming Sunday (June 3 2012):
Salt, We Misjudged You
By GARY TAUBES
Humans need salt
We all need salt for the proper operation of the nerves and muscles, and when we exercise heavily we sweat it out in copious quantities which demand replacement, as everyone now agrees:
THE first time I questioned the conventional wisdom on the nature of a healthy diet, I was in my salad days, almost 40 years ago, and the subject was salt. Researchers were claiming that salt supplementation was unnecessary after strenuous exercise, and this advice was being passed on by health reporters. All I knew was that I had played high school football in suburban Maryland, sweating profusely through double sessions in the swamplike 90-degree days of August. Without salt pills, I couldn’t make it through a two-hour practice; I couldn’t walk across the parking lot afterward without cramping.
Dept of Agriculture, CDC say its dangerous
However, in all other circumstances we are being loudly advised to avoid salt because it raises blood pressure and risks premature death, and the federal authorities have made it the number one dietary bugbear, labeled as dangerous as cigarettes:
While sports nutritionists have since come around to recommend that we should indeed replenish salt when we sweat it out in physical activity, the message that we should avoid salt at all other times remains strong. Salt consumption is said to raise blood pressure, cause hypertension and increase the risk of premature death. This is why the Department of Agriculture’s dietary guidelines still consider salt Public Enemy No. 1, coming before fats, sugars and alcohol. It’s why the director of the Centers for Disease Control and Prevention has suggested that reducing salt consumption is as critical to long-term health as quitting cigarettes.
But evidence remains weak
When Taubes researched it thoroughly in 1998, he found, however, that after 25 years of advice to cut down salt the scientific evidence for salt as a cause of hypertension was slim, as even the editor of JAMA agreed:
And yet, this eat-less-salt argument has been surprisingly controversial — and difficult to defend. Not because the food industry opposes it, but because the actual evidence to support it has always been so weak.
When I spent the better part of a year researching the state of the salt science back in 1998 — already a quarter century into the eat-less-salt recommendations — journal editors and public health administrators were still remarkably candid in their assessment of how flimsy the evidence was implicating salt as the cause of hypertension.
“You can say without any shadow of a doubt,” as I was told then by Drummond Rennie, an editor for The Journal of the American Medical Association, that the authorities pushing the eat-less-salt message had “made a commitment to salt education that goes way beyond the scientific facts.”
Now studies say salt reduction is dangerous
On the other hand, restricting salt has its own dangers. Studies in the last two years suggest harm if we stick to USDA and CDC guidelines, possibly even leading to earlier death. Salt makes us thirsty but the increase in blood pressure with eating more salt only lasts until our kidneys eliminate the excess salt. Is there a long term penalty if we often eat excess salt? In 1972 we only knew that populations that ate little salt had little hypertension, and that rats given the equivalent of 60 times the salt eaten by the average American got hypertension.
While, back then, the evidence merely failed to demonstrate that salt was harmful, the evidence from studies published over the past two years actually suggests that restricting how much salt we eat can increase our likelihood of dying prematurely. Put simply, the possibility has been raised that if we were to eat as little salt as the U.S.D.A. and the C.D.C. recommend, we’d be harming rather than helping ourselves.
WHY have we been told that salt is so deadly? Well, the advice has always sounded reasonable. It has what nutritionists like to call “biological plausibility.” Eat more salt and your body retains water to maintain a stable concentration of sodium in your blood. This is why eating salty food tends to make us thirsty: we drink more; we retain water. The result can be a temporary increase in blood pressure, which will persist until our kidneys eliminate both salt and water.
The scientific question is whether this temporary phenomenon translates to chronic problems: if we eat too much salt for years, does it raise our blood pressure, cause hypertension, then strokes, and then kill us prematurely? It makes sense, but it’s only a hypothesis. The reason scientists do experiments is to find out if hypotheses are true.
In 1972, when the National Institutes of Health introduced the National High Blood Pressure Education Program to help prevent hypertension, no meaningful experiments had yet been done. The best evidence on the connection between salt and hypertension came from two pieces of research. One was the observation that populations that ate little salt had virtually no hypertension. But those populations didn’t eat a lot of things — sugar, for instance — and any one of those could have been the causal factor. The second was a strain of “salt-sensitive” rats that reliably developed hypertension on a high-salt diet. The catch was that “high salt” to these rats was 60 times more than what the average American consumes.
Hypothesis lacked evidence but became fact
From this and other admittedly “inconclusive and contradictory” evidence sprang the public eat-less-salt campaign.
Still, the program was founded to help prevent hypertension, and prevention programs require preventive measures to recommend. Eating less salt seemed to be the only available option at the time, short of losing weight. Although researchers quietly acknowledged that the data were “inconclusive and contradictory” or “inconsistent and contradictory” — two quotes from the cardiologist Jeremiah Stamler, a leading proponent of the eat-less-salt campaign, in 1967 and 1981 — publicly, the link between salt and blood pressure was upgraded from hypothesis to fact.
Flimsy DASH-Sodium study became gospel
Massive spending by the NIH since has failed to confirm the belief, however. All we have is the 2001 DASH-sodium study which in a 30 day trial suggested that less salt would lower blood pressure a little.
In the years since, the N.I.H. has spent enormous sums of money on studies to test the hypothesis, and those studies have singularly failed to make the evidence any more conclusive. Instead, the organizations advocating salt restriction today — the U.S.D.A., the Institute of Medicine, the C.D.C. and the N.I.H. — all essentially rely on the results from a 30-day trial of salt, the 2001 DASH-Sodium study. It suggested that eating significantly less salt would modestly lower blood pressure; it said nothing about whether this would reduce hypertension, prevent heart disease or lengthen life.
2011 Cochrane metastudy finds no proven benefit, NEJ in 1972 said why lower intake might be dangerous
Two meta-reviews by Cochrane last year found cutting back reduced blood pressure but didn’t provably reduce heart disease or death rates, and that the effect of low salt diets was unknown.
While influential, that trial was just one of many. When researchers have looked at all the relevant trials and tried to make sense of them, they’ve continued to support Dr. Stamler’s “inconsistent and contradictory” assessment. Last year, two such “meta-analyses” were published by the Cochrane Collaboration, an international nonprofit organization founded to conduct unbiased reviews of medical evidence. The first of the two reviews concluded that cutting back “the amount of salt eaten reduces blood pressure, but there is insufficient evidence to confirm the predicted reductions in people dying prematurely or suffering cardiovascular disease.” The second concluded that “we do not know if low salt diets improve or worsen health outcomes.”
Italians, others have now shown harm to heart patients
But restricting salt even to the government advised ceiling can be harmful, continues Taubes. According to a “slew of studies” covering 100,000 people in 30 countries, human salt consumption is stable among populations over time, including in the US for the last fifty years despite the eat-less-salt campaign. In other words, there seems to be a steady physiological need, and it is more than the one teaspoon a day advised by the US government. The normal salt intake ie the average global personal intake turns out to be one and a half teaspoons, fifty per cent more than the federal safety ceiling for under 50s, and double the safe limit advised for the old or sick.
Meanwhile, Italian clinical trials revealed four years ago that limiting salt consumption actually increased the death rate of heart failure patients. Four other studies – of diabetics Type 1 and 2, of healthy Europeans and of heart failure patients – show that lower than average salt consumption risks heart disease.
With nearly everyone focused on the supposed benefits of salt restriction, little research was done to look at the potential dangers. But four years ago, Italian researchers began publishing the results from a series of clinical trials, all of which reported that, among patients with heart failure, reducing salt consumption increased the risk of death.
Those trials have been followed by a slew of studies suggesting that reducing sodium to anything like what government policy refers to as a “safe upper limit” is likely to do more harm than good. These covered some 100,000 people in more than 30 countries and showed that salt consumption is remarkably stable among populations over time. In the United States, for instance, it has remained constant for the last 50 years, despite 40 years of the eat-less-salt message. The average salt intake in these populations — what could be called the normal salt intake — was one and a half teaspoons a day, almost 50 percent above what federal agencies consider a safe upper limit for healthy Americans under 50, and more than double what the policy advises for those who aren’t so young or healthy. This consistency, between populations and over time, suggests that how much salt we eat is determined by physiological demands, not diet choices.
One could still argue that all these people should reduce their salt intake to prevent hypertension, except for the fact that four of these studies — involving Type 1 diabetics, Type 2 diabetics, healthy Europeans and patients with chronic heart failure — reported that the people eating salt at the lower limit of normal were more likely to have heart disease than those eating smack in the middle of the normal range. Effectively what the 1972 paper would have predicted.
Skeptics must be industry shills, say salt limiters
Those that defend salt restriction in the face of all this evidence that it damages health usually accuse the skeptics of being in the pocket of the food industry, says Taubes, who reaches back to his 1998 piece for a quote from a NIH official.
Proponents of the eat-less-salt campaign tend to deal with this contradictory evidence by implying that anyone raising it is a shill for the food industry and doesn’t care about saving lives. An N.I.H. administrator told me back in 1998 that to publicly question the science on salt was to play into the hands of the industry. “As long as there are things in the media that say the salt controversy continues,” he said, “they win.”
Typical denial continued at recent Salt hearings
He says that the FDA and Department of Agriculture continue to confer on how to push the public into eating less salt without reviewing whether the policy makes any sense in the light of the recent research, which they ignore or dismiss as nothing new. This confirmation bias has been in place for decades, sorry to say. Scientists have no business indulging in a weakness in scientific thinking that Huxley pointed out a hundred and fifty years ago.
When several agencies, including the Department of Agriculture and the Food and Drug Administration, held a hearing last November to discuss how to go about getting Americans to eat less salt (as opposed to whether or not we should eat less salt), these proponents argued that the latest reports suggesting damage from lower-salt diets should simply be ignored. Lawrence Appel, an epidemiologist and a co-author of the DASH-Sodium trial, said “there is nothing really new.” According to the cardiologist Graham MacGregor, who has been promoting low-salt diets since the 1980s, the studies were no more than “a minor irritation that causes us a bit of aggravation.”
This attitude that studies that go against prevailing beliefs should be ignored on the basis that, well, they go against prevailing beliefs, has been the norm for the anti-salt campaign for decades. Maybe now the prevailing beliefs should be changed. The British scientist and educator Thomas Huxley, known as Darwin’s bulldog for his advocacy of evolution, may have put it best back in 1860. “My business,” he wrote, “is to teach my aspirations to conform themselves to fact, not to try and make facts harmonize with my aspirations.”
A Robert Wood Johnson Foundation Independent Investigator in Health Policy Research and the author of “Why We Get Fat.”
A classic case of bad paradigm resistance to correction?
Strangely enough, Gary Taubes doesn’t mention that clinging to an unjustified hypothesis far past its due date – in fact for centuries – is still typical behavior in medicine, as it is in most academic fields. To err in this way is part of human nature, as difficult to root out in medicine as anywhere else. The power of a universal belief, even one where the evidence is pointing in another direction, can never be under estimated in human affairs, and especially in health and medicine.
That was in fact the theme of an exceptional book published in 2008, Bad Medicine: Doctors Doing Harm Since Hippocrates, by David Wootton, a historian at the University of York who pointed out that for 2300 years doctors did their patients no good whatsoever – aside from the placebo effect – and when improvement did come they were actively resisted.
Perhaps that was why our last post on the topic of salt reserved judgment on whether the idea that less is better was valid, a notion which anyway contradicted our instincts which tell us that salt is too necessary for animal life to be a danger at the level of intake that comes with a sane diet which avoids fast foods and packaged products, or any of the other nutritionally distorted rubbish which commerce offers us in this very slowly reforming economy.
We were also advised by the resident nutritional expert at home of her summary judgment that it was wrong that it was nonsense but that, of course, is another story.
The ageless Yanomamos
However, despite our personal liking for pink Himalayan salt sprinkled liberally on meat and veg we have the higher responsibility of delivering the edict of the best research available on the topic, so how does Taubes’s myth busting stand up in the light of the literature?
We’re not sure that our original post on this topic, two years ago, Salt Fights Back with Science needs much updating, since we did mention what seems to us to be the key to all this: humans need a balance between sodium and potassium intake, and it is the imbalance which modern commerce encourages with its excessive emphasis on salt as a taste enhancer that needs to be limited to avoid serious problems.
Where the salt prejudice really comes from
In fact it is wrong to imply as Gary Taubes does that there is very little in the literature arguing that salt intake should be limited, if this balance is the topic. The classic paper on the potassium-sodium ratio is Dietary, Total Body, and Intracellular Potassium-to-Sodium Ratios and Their Influence on Cancer.
Authored by biomathematician Birger Jansson at the M.D. Anderson Cancer Center 22 years ago, it observes human evolution from 30,000 feet and makes the general point that one of the great changes in human diet over the last few thousand years has been the liberal use of salt in cooking and preserving food.
Since over the same short evolutionary time our intake of potassium has dwindled, except for the few of us who love flounder, which provides 166 mg per ounce, or bananas, which contain 440 mg of potassium each medium size fruit, or avocado, which is the champion at 660 mg per half avocado, the ratio between K and Na in our diet has gone down perhaps 20 times.
In fact, modern urban humans who neglect fruit and vegetables may in fact eat about 100 to 200 times more sodium to potassium than the Yanomamo Indians in the Amazon jungle, who with massacres and disease have now been reduced to less than 25,000.
These famous Paleolithic holdovers do not eat salt and are still clinging to a Stone Age diet rich in potassium from cooking bananas. With evolution still needing a few millennia to catch up with this change, it has been blamed for major modern ailments by many researchers, including accelerated aging, none of which are seen among the Yanomamos, who typically lived till 75 or more until Western civilization came upon them:
One of the greatest changes in the human diet, a change that has occurred only within the past few thousand years, is the immense increase in the intake of sodium (Na) caused by use of table salt in the preparation and preservation of food. At the same time, man’s intake of potassium (K) has decreased. The result is that from Paleolithic times to modern times the dietary K/Na ratio has been reduced by a factor of about 20. Based on a comparison of modern people in civilized areas with the primitive Yanomamo Indians in South America (who do not eat salt but who do grow and eat potassium-rich cooking bananas), this factor may even be on the order of 100 to 200. Humans, who initially had to adapt to retain sodium from a sodium-poor diet and to excrete potassium from a potassium-rich diet, have not yet evolutionarily adapted to today’s high-sodium, low-potassium diet. This failure has caused increased rates of a number of diseases in civilized man, among them cancer. The influence of the K/Na ratio on cancer development–first discovered by epidemiologic studies–has been confirmed by various means, such as dietary studies, gerontological studies, studies of relationships between hyper- and hypokalemic diseases and cancer, and review of the cellular changes of this ratio induced by carcinogenic and anticarcinogenic agents. Recently, animal experiments have also confirmed the results. The recommended dietary K/Na ratio should be well above 1, preferably 5 or higher, and the cellular K/Na ratio should be above 10.
Albert Schweitzer, the organ playing Bach enthusiast and medical missionary who won the Nobel for his humanitarian efforts, was one of the first to bring this point to international attention. Ministering to the natives of Gabon in French Equatorial Africa, he found his efforts were being thwarted by the enthusiasm of black Africans for the salted diet of white people, which they took to be more civilized, presumably.
“Based on my own experience, going back to 1913, I can say, if cancer occurred at all (in Gabon and its surroundings at that time) it was very rare bu that it has become more frequent since…. It is obvious to connect the fact of increase of cancer with the increased use of salt by the natives. For the past forty years, practical experience was gathered about the effects of salt limitation upon diseases of the kidneys. It was shown just here that radical limitation of salt intake, which corresponds to the usual saltless nutrition, decreases the burden on the (black Africans’) diseased kidneys. As soon as the diseased kidneys are not over-irritated and over-burdened by the excessive intake of chlorides in nutrition, they recover in an amazingly short time and … eliminate more NaCl on a saltless diet than on the salt-rich diet!”
Of course, as Taubes would point out, it was a judgment call on the part of Schweitzer that it was the salt that was responsible for increased cancer in Gabon, and not a result from an epidemiological study that might have blamed something else. But Schweizer had observed that “many natives, especially those living in larger communities, do not now live as formerly–they lived almost exclusively on fruits and vegetables, bananas, cassava, ignam (yam), taro, sweet potatoes and other fruits. They now have begun to live on condensed milk, canned butter, meat-and-fish preserves, and bread.” Since the preservation was with salt, he traced the appearance of cancer, appendicitis and other degenerative diseases to that substance.
But as Taubes points out, correlation is not necessarily causation, and “those populations didn’t eat a lot of things — sugar, for instance — and any one of those could have been the causal factor. ” Well, maybe. The infatuation with sugar is certainly a well known candidate for causing poor health in the West. But there are other studies which link salt with health problems beyond hypertension, including cancer, as Schweizer surmised, if the balance with potassium is not kept up – and with salt added merrily to almost everything edible, for those who don’t cook this balancing act is very hard to do without supplements.
Flat contradictions in Times letters
Here are the letters that the Times has now published in answer to Taubes (we are writing a few days later), briefly and flatly asserting that Taubes is up the creek on this one.
They state that a huge amount of studies of all kinds have established that a high sodium diet brings high blood pressure which threatens heart attacks, strokes and kidney disease, and now a 15 year study has shown the risk is reduced by 30% if salt is curbed. Taubes has “cherry picked a vast literature to suit his needs” and contributed nothing to the debate, merely complicating the advice physicians must give individual patients, particularly the elderly, who might benefit from the “small” effect of lowering hypertension that salt reduction brings. We certainly need lower salt food products as the Institute of Medicine recommended in 2010:
In “Salt, We Misjudged You” (Sunday Review, June 3), Gary Taubes contends that decades of studies have failed to demonstrate that diets high in salt, or sodium, are harmful, and that advocates of restricting salt “essentially rely on the results from a 30-day trial of salt.”
In fact, huge amounts of evidence from animal, clinical, cohort and intervention studies demonstrate that high-sodium diets raise blood pressure, and that higher blood pressure promotes heart attacks, strokes and kidney disease.
Critics of efforts to reduce salt acknowledge that studies show those two relationships, but demand studies that directly link lower salt to lower risk of heart disease. Such studies have now been done.
The 15-year follow-up on the Trials of Hypertension Prevention found a 30 percent reduction in the risk of heart attacks, strokes and other cardiovascular events.
As the Institute of Medicine recommended in 2010, it’s high time that the Food and Drug Administration began limiting sodium in packaged and restaurant foods.
MICHAEL F. JACOBSON
Center for Science in the Public Interest
Washington, June 4, 2012
Gary Taubes does little to advance an objective view of the effect of salt intake on health. He has cherry-picked a vast literature on the subject to suit his needs. What we know is that reducing salt intake lowers blood pressure, particularly in the elderly with hypertension, and that anything that reduces blood pressure reduces cardiovascular risk. The effect is small, but the cost is minimal.
Whether everyone should reduce his or her salt intake is a separate question, for which the debate continues. For those who need to restrict their salt intake, however, local availability of food products with low salt content is essential.
Mr. Taubes’s article only turns up the heat on the salt controversy without shedding any light, leaving physicians the onerous task of explaining once again the need for salt restriction to their patients.
F. JOHN GENNARI
Burlington, Vt., June 4, 2012
The writer is professor emeritus at the University of Vermont College of Medicine.
I have been instructed to sprinkle a teaspoon of salt over my food to avoid muscle cramps. My husband suffers high blood pressure and has been told to avoid salt. Doctors and health policy experts should stop taking a one-size-fits-all approach and admit that everyone has a unique metabolic constitution, and that salt needs vary tremendously.
Darien, Conn., June 3, 2012
In other words, not only is Taubes wrong to say that there aren’t enough studies showing that high sodium raises blood pressure, or that high blood pressure is dangerous, but there now studies which link the two directly, such as the “15-year follow-up on the Trials of Hypertension Prevention study” which shows that low salt can help lower the risk 30% (we assume that low salt was not the only factor involved).
Michael Jacobsen we know to be a reliable source on such matters. Is this a stake through the heart of Taubes’ troll? Is the clever Taubes merely muddying clear water, as the Vermont Professor Emeritus scolds?
One alternative treatment book is worth quoting here. Not only are studies which link a lower salt diet to improvement in health easy to find, but many, according to The Gerson Therapy: The Amazing Nutritional Program for Cancer and Other Illness by Charlotte Gerson and Morton Walker DPM (2001, Twin Streams, Kensington)” show it to be useful for many other maladies, including cancer.
“Much more needs to be explained about ingesting no salt and adding potassium, sodium’s mineral antagonist. … Not only does elevated blood pressure improve from high potassium usage and reduced sodium intake, but the saltless diet is responsible for reversing both acute and chronic illnesses of all types such as arthritis, diabetes, multiple schlerosis, cardiovascualr disease, autoimmune diseases, chronic fatigue syndrome and many others.”
The Gerson concept in cancer is that a high potassium-low sodium diets acts against tumor formation.
(To be cont.)