CSPI assertion: “Doctors first suspected 100 years ago that salt (sodium chloride) increases blood pressure.” (Salt: The Forgotten Killer, p. 1)
Fact: As long ago as 2,000 B.C. when the famous Chinese “Yellow Emperor” Huang Ti recorded salt’s association with a “hardened pulse,” we have known of a relationship between salt and blood pressure. (http://www. saltinstitute.org/52.html)
CSPI assertion: “Epidemiologists found that populations, such as in northern Japan, that consume high levels of sodium (almost all from salt) suffer high rates of hypertension, while populations with low sodium intakes (hunter-gatherer tribes) have low rates.” (p. 1)
Fact: The largest epidemiologic study of the association of population blood pressures with sodium intakes, Intersalt, found no evidence supporting its primary hypothesis that posited that there would be a direct relationship of systolic blood pressure and sodium excretion (sodium is most reliably measured by 24-hour urinary excretion analysis). Likewise, the secondary hypothesis of a direct relationship with diastolic pressure was also found unsupported in this study of more than 10,000 persons in 53 centers around the world. If the four remote primitive populations are excluded, the relationships even become inverse, though not statistically significant. (Intersalt citation). While epidemiologic studies cannot prove causality, the Intersalt data provide no comfort to CSPI’s assertion.
CSPI assertion: “Researchers also noted that in people living in industrialized nations—but not in tribes eating low-sodium diets—blood pressure tended to rise with age.” (p. 1)
Fact: This is also a factoid from the Intersalt Study, though a couple amplifications are required. First, Intersalt was a snapshot view, not a longitudinal study observing the same subjects as they aged. The researchers (and CSPI) assumed that no other factors in either the industrialized or primitive societies might be responsible for the observation that older cohorts in the study had higher blood pressures. In fact, the starting blood pressures among the primitive peoples in the study were higher, so their rise with age was flatter. Moreover, in comparing industrialized societies with primitive societies, there are many variables affecting blood pressure, not just dietary sodium. A study by Harvard University researchers of a high-sodium-consuming primitive people who migrated to cities found that their blood pressures increased even though their sodium intakes did not. (Hollenberg citation)
CSPI assertion: “Louis Tobian, Jr. … (said): ‘One must realize that prehistoric man for 3 million years was on a low-salt diet.” (p. 1)
Fact: Yes, Dr. Tobian made that statement. Dr. Tobian has conducted persuasive research showing a benefit of potassium on stroke risk and has projected a drastic curtailment of dietary potassium from prehistoric societies to today. Not that prehistoric men lived long or healthy lives, but research in the last decade has confirmed earlier observations that it is the balance of potassium (also calcium and magnesium) with sodium that determines whether blood pressure responds to changes in dietary sodium. That modern societies do not consume Paleolithic diets may be true, but inclusion of this observation is misleadingly irrelevant to the question of whether any particular level of dietary sodium is healthy or unhealthy.
CSPI assertion: “Subsequent research has quantified not just the effects of salt on blood pressure but also the health and economic benefits of lower-sodium diets. Increased blood pressure causes an estimated two-thirds of strokes and almost half of all heart attacks around the world.” (p. 1, citing Murray CJL, Lauer JA, and Hutubessy RCW. Effectiveness and costs of interventions to lower systolic blood pressure and cholesterol: a global and regional analysis on reduction of cardiovascular-disease risk. Lancet. 2003; 361:717–25.)
Fact: The Murray et al study is yet another, like CSPI’s that builds a model based on salt/blood pressure studies and projections of population health benefits; it is not an outcomes study at all.
CSPI assertion: “Consuming less sodium is one of the single most important ways to prevent cardiovascular disease.” (p. 1)
Fact: There are a dozen observational studies on this question; not a single clinical trial. There is no comfort in the evidence for the CSPI assertion. More importantly, the National Heart, Lung and Blood Institute’s blood pressure treatment guidelines ranks salt reduction well behind more promising strategies of losing weight, limiting alcohol and increasing intakes of fruits, vegetables and low-fat dairy products among lifestyle interventions.
CSPI assertion: “Despite such clear expressions of concern by top health and policy experts, the battle against high blood pressure is being lost.” (p. 2)
Fact: The definitive evidence shows dramatic gains in the battle against high blood pressure over many years. Recently, with the spurt of obesity, the largest factor in blood pressure, our national efforts have plateaued, but, no, CSPI, the sky is not falling.
CSPI assertion: “Sodium consumption has been rising, not falling.” (p. 2)
Fact: We have had laboratory tests for urinary sodium for the past century. During that entire 100 years, sodium excretion (and, hence, intakes) has been constant. 
CSPI assertion: “Health experts from the Surgeon General on down have decried diets high in sodium. But they’ve never taken strong policy actions or mounted compelling educational programs to correct the problem.” (p. 2)
Fact: In 1981, FDA under the leadership of Arthur Hull Hayes began a vigorous public education campaign and enlisted the assistance of food manufacturers to reduce the amounts of salt in their food products. Salt was demonized as “Killer Salt” and a cover of Time magazine looked much like the CSPI report. Americans recorded an astounding responsiveness with upwards of 60 percent of the population declaring they believed salt damaged their health—for well over a decade, concern about salt far outstripped any other dietary concern such as that for obesity, fat intake, cholesterol, etc.
CSPI assertion: “According to the Salt Institute, per capita production (of food grade salt) declined significantly for several years beginning in 1978, but then increased steadily to 1998.” (p. 2)
Fact: The Salt Institute reports neither salt production nor per capita salt production. We do report food grade salt sales, but these include amounts that are used in food processing, but never ingested. Beginning in 1978, sales did not decline until after the U.S. Dietary Guidelines in 1980 and then, particularly, with the FDA campaign in 1981. The decline lasted two years and continues to rise today as U.S. population increases.
CSPI assertion: “Sodium intake has drifted steadily upwards, increasing from about 2,300 milligrams (mg) per day in the early 1970s to about 3,300 mg in 1999-2000.” (p. 2)
Fact: CSPI admits its data are from dietary recall studies, notoriously unreliable. Relevant data are the baseline sodium intake levels of populations entering clinical trials. These show a remarkably consistent range of sodium intake with the average of 3,200—3,600 mg of sodium a day.
CSPI assertion: “In the 1970s and 1980s, the ratio of sodium to calories increased sharply… Since 1987-88, sodium intake has continued to increase, but the ratio of sodium to calories has remained fairly constant.” (p. 3)
Fact: This is the only original observation in the report and is completely undocumented. Most experts agree that in dietary recall studies (such as those used by CSPI) respondents’ recall of caloric intake is the least reliable.
CSPI assertion: Regarding the “best way to measure sodium intake”: urinary sodium testing “is expensive, so sample sizes are relatively small and not representative of the entire population.” (p. 3)
Fact: Expensive, yes, but the Intersalt Study measured more than 10,000 individuals worldwide using identical methods and a single laboratory. They found remarkable consistency. You’ll never find a researcher who can’t figure out a way to seek more information if funding is available, but there is no data that challenge the Intersalt findings.
CSPI assertion: “…the increase in salt and fluid within the circulatory system causes a narrowing of the blood vessels, which further increases pressure and reduces the flow of blood to the tissues.” (p. 11)
Fact: False, at least in any normal salt intake ranges.
CSPI assertion: “Reducing Blood Pressure Reduces Cardiovascular Disease.” (p. 13)
Fact: All of the “studies” cited employ estimation models that assume that blood pressure alone determines cardiovascular outcomes without, in fact, measuring those outcomes. Their design is fatally flawed. Estimates derived from unvalidated models exemplify the computer observation: “garbage in, garbage out.”
CSPI assertion: Salt intake worsens calcium excretion, kidney stones, asthma, heliocobac-ter pylori and stomach cancer. (p. 15)
Fact: Pure junk science except for calcium excretion, but to what health effect? Drink your milk.
CSPI assertion: “A study of overweight people found that a 2,300 mg higher daily consumption of sodium was associated with an 89
percent increase in stroke mortality and a 44 percent increase in mortality from coronary heart disease.” (after correcting for blood pressure) (p. 15, citation to He J, Ogden LG, Vupputuri S, et al. Dietary sodium intake and subsequent risk of cardiovascular disease in overweight adults. JAMA. 1999; 282:2027–34.)
Fact: In the entire population, the study could identify no health benefit. Without question some individuals and subgroups respond differently than others. If some groups get great benefit and overall there is no effect, than some (unidentified) individuals and subgroups must enjoy reduced risk on much higher salt diets.
CSPI assertion: “…an earlier Salt Institute letter that unsuccessfully sought to derail the 2000 Dietary Guidelines… ” (p. 25)
Fact: While the Salt Institute opposed the salt guideline in 2000, it at no time either advocated or worked to “derail the 2000 Dietary Guidelines.” This is a blatant falsehood.
CSPI assertion: “The Salt Institute… contends that the best way to fight hypertension is to consume… a diet low in saturated fat and cholesterol…” (p. 25)
Fact: The Salt Institute favors the DASH Diet as a means of reducing or eliminating salt sensitivity in blood pressure. It does not specifically endorse interventions on saturated fat or cholesterol. We believe that improving dietary quality will help control high blood pressure, and endorse the DASH Diet in hopes of improving health, not just blood pressure.
CSPI assertion: “What the institute refuses to recognize… is that when a health problem affects a huge segment of the population—110 million Americans have hypertension or pre-hypertension—a more encompassing society-wide solution is needed.” (p. 25)
Fact: Elevated blood pressures are important intermediate variables, not a disease end point. They indicate something is wrong with the body and are multi-factoral. The Salt Institute clearly recognizes that cardiovascular events impose an unacceptable burden on American society. Wasting resources on interventions that have no proven benefit is not an effective response. Until we know the net health outcomes impact of a population intervention such as salt restriction, we should be cautious. As journalist Gary Taubes observed in his award-winning article “The (Political) Science of Salt,” as the evidence continues to accumulate, rather than giving greater confidence that salt restriction might be effective, the evidence is producing just the opposite result—the more we know, the less certain we can be that this is a good idea.

Share.

Comments are closed.