Sodium Recommendations, Ground Hog’s Day and The New York Times
” A new study published in the American Journal of Hypertension finds evidence that the average daily sodium intake of most Americans is actually associated with better health outcomes than intake levels currently recommended by the CDC and major health departments, which are now being viewed by many in the scientific community as excessively and unrealistically low.
The study, “Compared With Usual Sodium Intake, Low-and Excessive-Sodium Diets Are Associated With Increased Mortality: A Meta-Analysis,” concluded that 2,645 – 4,945 mg of sodium per day, a range of intake within which the vast majority of Americans fall, actually results in more favorable health outcomes than the CDC’s current recommendation of less than 2300mg/day for healthy individuals under 50 years old, and less than 1500 mg/day for most over 50 years. This study was a combined analysis of 25 individual studies, which measured results from over 274,683 individuals. “
I’ve seen some people surprised by this, but for anyone following the issue and how it is reported it isn’t surprising, instead you feel more like Bill Murray in Ground Hog’s Day. [Editor: Warning: selective quotes ahead]
Gina Kolata writing in the The New York Times, May 14, 2013:
In a report that undercuts years of public health warnings, a prestigious group convened by the government says there is no good reason based on health outcomes for many Americans to drive their sodium consumption down to the very low levels recommended in national dietary guidelines.
Those levels, 1,500 milligrams of sodium a day, or a little more than half a teaspoon of salt, were supposed to prevent heart attacks and strokes in people at risk, including anyone older than 50, blacks and people with high blood pressure, diabetes or chronic kidney disease — groups that make up more than half of the American population.
Gary Taubes writing in The New York Times, June 2, 2012:
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.”
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.
Nicholas Bakalar writing in The New York Times, November 28, 2011:
The scientists studied an international group of 28,880 men and women over age 55 at high risk for heart disease. They estimated salt intake by testing urine and followed the group for almost five years. The study appears in the Nov. 23 issue of The Journal of the American Medical Association.
The researchers found — unsurprisingly — that high sodium intake significantly increased the risk for heart problems.
But too little sodium was almost as bad as too much. Compared with those who excreted 4 to 6 grams of sodium daily, people who excreted 2 to 3 grams were at 19 percent greater risk for death from a cardiovascular event, and the less they consumed the greater their risk.
Nutritionists recommend a daily intake of 1.5 grams of salt for people with heart problems, a level that in this study increased the risk for cardiovascular death by 37 percent.
Gina Kolata writing in The New York Times, May 3, 2011:
The investigators found that the less salt people ate, the more likely they were to die of heart disease — 50 people in the lowest third of salt consumption (2.5 grams of sodium per day) died during the study as compared with 24 in the medium group (3.9 grams of sodium per day) and 10 in the highest salt consumption group (6.0 grams of sodium per day). And while those eating the most salt had, on average, a slight increase in systolic blood pressure — a 1.71-millimeter increase in pressure for each 2.5-gram increase in sodium per day — they were no more likely to develop hypertension.
“If the goal is to prevent hypertension” with lower sodium consumption, said the lead author, Dr. Jan A. Staessen, a professor of medicine at the University of Leuven, in Belgium, “this study shows it does not work.”
In 2010 they wrote approvingly about the FDA possibly establishing an upper limit per serving.
But the year before, Michael Alderman wrote in The New York Times, February 5, 2009:
The best available evidence on how salt consumption affects our health comes from observational studies, in which groups of subjects are investigated to identify any correlations between usual sodium intake and subsequent heart attacks and strokes. Nine such studies, looking at a total of more than 100,000 participants who consume as much sodium as New Yorkers do, have had mixed results. In four of them, reduced dietary salt was associated with an increased incidence of death and disability from heart attacks and strokes. In one that focused on obese people, more salt was associated with increased cardiovascular mortality. And in the remaining four, no association between salt and health was seen.
People who advocate curtailing salt consumption typically prefer to discuss two other observational studies from Finland and Japan, where salt consumption is generally higher than in the United States. In both of these, more salt was associated with more cardiovascular problems.
To be fair(ish) Jane Brody wrote in 2011 about a study that supported limiting sodium intake but suggested that the ratio to potassium intake was more important. But then, Jane Brody never stopped partying like it’s 1999. In the interest of balance, Michael Jacobson was critical of the Times 2013 reporting on the IOM paper. But then, everything Michael Jacobson says about nutrition should be taken with a grain of salt. (ouch!)
I don’t expect this cycle to stop playing out any time soon. Conventional wisdom never goes gently into that good night. From the Taubes piece:
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.”