Saline drip
Hyponatremia is a far more serious condition than was originally thought. While reviewing some of the standard therapies associated with symptoms, I came across some facts that caused me to do a double take. As anyone who has ever been admitted to hospital for treatment knows, the intravenous saline drip is standard therapy and the fastest way to deliver fluids and medications throughout the body. Normal saline drip is the commonly-used term for a solution of 0.91% salt (sodium chloride). The amount of saline infused depends largely on the particular needs of a patient, but on average is typically between 1.5 and 3 liters a day for an adult. So, in order to maintain an average adult in optimum health during a hospital stay, somewhere between 13.7 – 27.3 grams of salt per day is administered. Of course, that doesn't even include the salt that is consumed along with the food. If the hospital dieticians were able to provide meals that corresponded to the current recommended levels, this would add an additional 6 grams of salt for a total of somewhere between 20 and 33 grams of salt a day. And don't forget, every four hours or so, they come by to check on your blood pressure.
I wonder how hospitals will comply with the salt intakes recommended by the Dietary Guidelines Advisory Committee? After all, the Dietary Guidelines recommend 4 - 6 grams of salt per day, about 1/5 of what is currently administered in hospitals!!
Today's NY Times (free subscription) carries an opinion column by science editor John Tierney, "Salt Wars." It recounts the exchanges between medical experts over the advisability of asking the general population to reduce dietary salt and hits both of the key issues, which are:
- Is salt reduction even possible or is "salt appetite" a hard-wired physiological response by the body to its need for this necessary nutrient?
- If population salt reduction were achieved, would public health be improved?
The most interesting aspect of this debate among medical professionals is that those advocating for population salt reduction want to skip over these two questions. Tierney blows the whistle on them, quoting America's leading salt reductionist, Dr. Larry Appel, conceding that the data a "murky" and that there is no evidence of any change in American salt consumption, up or down, in recent decades. Said Appel: “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.”
To oblige Dr. Appel, while the data on any putative benefit of salt reduction is clearly all over the map with some studies supporting a benefit but more finding no benefit or even heightened risk, the data on the immutability of salt appetite is rather consistent and compelling -- government policies do not move salt consumption among people eating normal amounts of sodium (the U.S. intake is absolutely dead center among nations around the globe).
Recognizing the volatility of the issue, Tierney invited his readers to comment:
You’re welcome to weigh in on any of these issues, especially the question of what scientists really know about the effects of restricting salt. Should Washington follow New York City’s lead in pressuring food companies to take salt out of their products? Or has New York gone beyond what the evidence warrants, as argued by Elizabeth Whelan of the American Council on Science and Health ?
We have heard a lot in the media lately about salt and health. In fact, there has been an unceasing parade of talking heads and cranks that have emerged from the woodwork to repeat the urban legends on blood pressure and cardiovascular deaths that will result from our continued consumption of salt. The fact that cardiovascular disease death rates have plummeted in the last 30 years seems to be lost on these soothsayers. Another fact they conveniently ignore is that the Mediterranean countries that have such excellent cardiovascular figures eat far more salt than we do here in America and at that countries, which consume the highest levels of salt, such as Japan and Switzerland, also have the longest life expectancies. Oh well, how can actual evidence ever compete with a good scare story?
We're beginning to hear about the importance of reducing salt in the diets of young children. Unfortunately, much of what we hear does not coincide with what is being demonstrated in the medical literature.
In particular I refer to a review paper very recently published in Pediatrics, the Journal of the American Academy of Pediatrics, in November 2009. The article is titled Hyponatremia in Preterm Neonates - Not a Benign Condition . In this paper, authors Michael Moritz and Juan Carlos Ayus state that hyponatremia, or low sodium levels in the neonates pose a significant risk for future childhood development. These risks include reduced neuromotor abilities from infancy through later years as well as impaired growth and mental development. Hyponatremia has also been found to be a significant factor for hearing loss, cerebral palsy, intracranial hemorrhage and increased mortality - all because of low sodium levels in the blood resulting from decreased salt intakes.
Furthermore, the authors quoted research carried out in Israel demonstrating that low sodium levels lead to hyponatremic neonates weighing 30% more than their peers maintained at normal sodium levels and that hyponatremia in infants was predictive of increased salt appetite in adolescence and later years. So, once again, contrary to the urban legend of salt consumption leading to obesity, the evidence is exactly the opposite – it is low salt levels in neonates that lead to obesity.
The authors then went on to stress that the emerging literature also suggests that hyponatremia in adults can have very deleterious effects and may be an independent predictor of mortality in hospital patients, those with community acquired pneumonia, with congestive heart failure and liver disease. Chronic low salt levels produces neurologic impairment that affects both balance and attention deficit conditions in the elderly - effect similar to alcohol ingestion. These data were able to explain why low-salt levels are such an important cause of falls and bone fractures in the elderly. This is clinical evidence, not urban legend.
Nutrition and nutrition-related policy initiatives are not things to be trifled with and it's certainly not anything to be left to in competent activists and minimally-trained physicians parading around as nutritionist-wannabes. Neither should they be matters of gratuitous opinion. Nutrition is a key to health and any policies regarding nutrition have to be based upon strong, clinical evidence.
The USDA's Supplemental Program for Women, Infants and Children or WIC program provides food and nutritional information to low-income people who are at nutritional risk - yet, to qualify for the program, WIC foods must contain little or no added salt . Just look at the regulatory requirements for WIC-eligible foods. In particular, there is great concern over products such as vegetables and instant preparations containing vegetables that are required to be made without salt. Not only does this increase the chances for hyponatremia, but because children are so sensitive to the natural bitterness in vegetables, it is unlikely that they will eat them without the addition of salt, thereby robbing of the natural goodness these products contain.
Here again, falling victim to anti-salt propaganda, government bureaucrats in charge of this program have backed away from their responsibilities and blindly gone along with the urban legends and myth-information regarding salt, rather than heeding the published evidence in the medical literature.
As a result, the low income women, infants and children, who are most at nutritional risk have had these risks compounded by the additional risks related to low salt intakes and hyponatremia - risks leading to poor neuromotor development, impaired growth and mental development, hearing loss, cerebral palsy, brain hemorrhage and increased mortality – now how's that for government assistance?
Click the image to see the Vlog or check out the full SaltGuru video .
The UK's Food Standards Agency has made since-disproven claims to have achieved population sodium reduction. This week FSA and the Department of Health rolled out a new National Diet and Nutrition Survey .
The NDNS promises to use 24-hour urine samples (UNaV) to measure population sodium intakes -- the approach advocated by the Salt Institute in place of the dietary recall surveys FSA used to claim an overall sodium reduction. But, surprise, the results apparently didn't confirm the rosy projections of the press office. The report is silent on sodium with the excuse that "results from the urine analysis are not included in the current report as the sample size for year one is too small to report."
Not to worry, scientists have reviewed the data already -- and published an analysis that documents no reduction in sodium intake . So, Britons are safe from their government's mindless meddling -- at least for now. Last Fall, researchers reported in the Journal of the American Society of Nephrology:
UNaV and, thus, dietary sodium intake has varied minimally in the UK over the 25 yr encompassing these surveys. The mean sodium intake over the time period 1984 to 2008 was 150 mmol/d. Second, more than 6300 subjects, many providing multiple samples, are the source of these 24 h UNaV measurements from a variety of regions of the UK and Ireland, and they fall within a relatively narrow range.
Not shown, but assessed by us, was the individually determined mean and range of UNaV for women and men where the gender breakdown was available from the survey. Sodium intake for women was 129. Likewise, male sodium intake, which included a 1982 survey of only men living in London, was constant over the same period, although, as would be expected on a caloric basis, higher than that of women, 169.4. The male and female analyses excluded the three Intersalt sites, as the published data provided only the mean for the combined cohort. This statistical analysis of all available 24 h UNaV from the UK does not support recent FSA pronouncements that their national campaign directed at sodium reduction has achieved a significant reduction in the population.
Perhaps the next NDNS will "find" the urinary data these other scientists have already reported in the peer-reviewed literature.
The Mayor Bloomberg initiative (grandiosly referred to as the National Salt Reduction Program), possibly dreamed up by activist groups and leveraged through cronies at New York's health department and their friends at health commission offices around the country, reminds me of something I wrote some time back when I did the history of “Typhoid Mary.” It concerns the abuse of power exercised by Boards of Health and Health Commissions who feel they can, without fear of repercussion, dispense with civil rights in order to execute policies, even if there is no solid evidence to support them. In doing so, these bureaucrats make the self-indulgent leap from civil servants to civil masters without any permission from those they swore to serve.
The quote I am reminded of was by Dr. Josephine Baker, the person who first managed to take 'Typhoid' Mary Mallon into custody. Everyone else looked at Mary's decades-long illegal detention with a clear conscience after her death in custody. Only Dr. Baker spoke up and soberly stated what Mary, a poor Irish immigrant, was up against.
“Typhoid Mary made me realize for the first time what sweeping powers are vested in Public Health authorities. There is very little that a Board of Health cannot do in the way of interfering with personal and property rights for the supposed protection of the public health. Boards of Health have judicial, legislative and executive powers... There have been many typhoid carriers recognized since her time, but she was the first charted case and for that distinction she paid in a life-long imprisonment.”
We see the same mindless, hob-nail boot trampling going on with salt today. C.S. Lewis once said, "Of all tyrannies, a tyranny exercised for the good of its victims may be the most oppressive... those who torment us for our own good will torment us without end, for they do so with the approval of their own conscience."
A muddle of disingenuous advocates, ambitious civil servants and politicians, operating with manipulated evidence, has chosen salt reduction as their cause célèbre. These make-believe crusaders are infused with thought, “Focus on the journey, not the destination.”
Unfortunately, for the public there is a destination, and it is their freedoms and their health.
The former president of Canada's largest science based regulatory agency, the Canadian Food Inspection Agency, cautioned the public recently: "Don't be fooled. Science is always politicized." Ronald Doering argues in the National Post that we should not expect scientists to put aside their policy biases nor confess using their scientific credentials as participants in the policy arena:
That scientists should dress up their science advice as pure neutral science is understandable. For those with scientific expertise, it makes perfect sense to wage political battles through science because it necessarily confers to scientists a privileged position in political debate.
But, does it? Must we lower our high expectations that scientific experts can give us the "straight scoop" without injecting their personal policy preferences to bias their "scientific findings"? I think we can expect more from scientists. Dumbing down our sensibilities in considering scientific studies would result in substituting our own, non-expert biases and thwart progress in embracing new understandings of the reality of the world around us. Count us pro-science.
What can be said of the charge, then, that scientists have biases and their work can only be considered as a political statement? The scientific method is value-neutral. Every scientific study recognizes that the investigator has a "bias" in that the hypothesis to be tested is proposed because the scientist thinks it may offer explanatory value. It is the method itself that will save science from the bias towards confirming the hypothesis. The key here is to get agreement on the quality standards for performing the study and analyzing the results. Those, like Dr. Doering, so insist that we prioritize our understanding of "how policy is scientized and science is politicized" suggest that there is no consensus on standards of scientific inquiry. That's just plain wrong.
A generation ago, the late Dr. Archie Cochrane at Oxford University confronted this question: that scientists seemed to be reaching differing conclusions from the same body of evidence and he devised procedures that grew into the global "evidence-based medicine" movement currently promoted by his eponymous Cochrane Collaboration .
The critical component of evidence-based science is the rigorous separation of method and data. The method must be set out first and the data then gathered and analyzed using that method. It's the opposite of choosing the analytic method after the data have been examined to "discover" that the post-hoc hypothesis is confirmed.
I'm recently returned from the India-International Salt Summit in India and so my eye caught the news that, in the wake of ClimateGate, India has withdrawn from the International Panel on Climate Change (IPCC). India's environmental minister, Jairam Ramesh, was quoted observing: "There is a fine line between climate science and climate evangelism. I am for climate science."
For more than two decades, back to at least 1988 when the Intersalt Study was published, we've seen the same "theological" threat to science in the salt and health controversy. In fact, the shenanigans of the salt reductionist advocacy groups give theology a bad name. It's just the dogmatic rejection of science showing no general health benefit from salt reduction and even the futility of the public health campaign to alter salt intake levels once they are the the range that 90+% of the world's population ingests (the U.S. is right smack in the middle of this intake range).
So, we stand with Mr. Ramesh: we're for nutrition science and not nutrition evangelism in the salt and health debate.
The debate over salt and health continues to wallow at low levels of evidence: opinion or, at best, only observational outcomes studies (with one exception: a randomized trial showing that heart failure patients put on low salt diets suffered worse outcomes).
As a result, the Salt Institute, Grocery Manufacturers Association and many leading researchers are calling for a controlled trial of the health outcomes of the current policy of promoting salt reduction for everybody.
But while the salt controversy simmers, medical scientists are "moving on," recognizing that even well-designed randomized trials (RCTs) can produce results that can mislead policy decisions. TheHeart.org recently carried Sue Hughes' admonition to insist on "clinically significant" RCTs. Hughes summarizes an article in the February 2 issue of the Journal of the American College of Cardiology by Drs. Sanjay Kaul and George Diamond. That issue of JACC also contains an instructive article by Gregg W. Stone and Stuart J. Pocock on the same subject: the clinical significance of RCTs.
So, while salt reduction advocates want us to turn a blind eye to the conceded fact that six of the eight subgroups in the DASH-Sodium trial had no statistically-significant blood pressure improvement (and those subgroups would represent the overwhelming majority of the general public), the discussion in JACC is that statistical significance is not even enough: the findings also need to make a clinical difference. We read "clinical difference" to mean improved outcomes, not simply plausible theoretical modeling results.
Something public health nutrition policy-makers should consider.
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