Hanneman letter to Canadian Transport Minister David Collenette Urging that Highway Operations Become Part of Canada's Road Safety Vision 2010, August 29, 2002

When the Salt Institute submitted its Second Supplemental Statement to the FDA on March 20, 2008, it pointed out that it was impossible to address any specific concerns with the petition voiced by others because the ongoing transition from the FDA Dockets Management System to the Federal Dockets Management System did not allow us to view the range of comments submitted. Indeed, we were unable to see our own comments posted on the Regulations.gov website.

Because of the unique circumstance resulting from the transition, the Salt Institute requested a 60 day extension to the comment submission deadline so that all concerned parties have a full opportunity to review all comments made and add any additional information pertaining to them.

We note that the Regulations.gov website now has a significant number of comments posted although we were unable to see the Salt Institute First Supplemental Statement submitted on March 4, 2008. This comment was particularly pertinent as it described the latest scientific publications focused on the significant health risks associated with limiting salt in the diet. One of the publications cited was very recent (April, 2008) and indicated the risks for healthy young adults who were limited to 2,300 mg sodium per day. The significance of this publication is that 2,300 mg per day is the upper limit recommended by the dietary guidelines.

After reviewing the comments now available on the Regulations.gov website, the Salt Institute is submitting a third supplement in response to one comment we have read which specifically refers to the Salt Institute input to the FDA on this matter. Because the Salt Institute was specifically mentioned in this comment, we feel obliged to respond. Even though this is past the official closing date, the Salt Institute hopes these comments will be accepted in light of our request for an extension and in the constructive spirit with which they are submitted.

Needless to say, any issue regarding the health of our citizens requires the most objective and comprehensive evaluation we can carry out. Interpretation of data should not be biased by positions that are profit-, ego-, or career-driven.

We would like to address the comments submitted on behalf of World Action on Salt and Health (WASH), an advocacy group whose entire “mission is to achieve a reduction in dietary salt intake.” We note they refer to the Salt Institute as “a public relations company defending the interests of salt extractors and manufacturers worldwide.” That is incorrect. The Salt Institute is a non-profit association whose mission is to “Increase understanding regarding the contributions of responsible salt use, enabling improved quality of life, better health and safer transportation.” We contrast the two mission statements because they reveal the inherent bias of each group. We are dedicated to finding legitimate ways for society to use salt and they are dedicated to reducing dietary salt use, period. Our position is that the science should determine the legitimacy of any intervention; they advocate general salt reduction, not basing it on scientific outcomes. No doubt, we all favor improving public health. We just haven’t pre-judged the science.

Salt reduction being the raison d’être of WASH, it is unsurprising that the group’s submission fails the test of providing an objective evaluation of the role of salt in health. It ignores or misstates the evidence that suggests that salt intake reduction may not be in the interests of consumers. To admit such would be to render the WASH mission obsolete. (It should be noted that several individual WASH members submitted separate comments to the FDA on this issue, including Jacobsen, Appel and Kaplan, who did not divulge their affiliation with this advocacy effort.)

With reference to the WASH statement on page 11 regarding the Intersalt Study, WASH gives the impression that the Salt Institute was the sole voice objecting to the authors’ interpretation of results. In fact a great many people disagreed with the analysis. The initial analysis, in fact, conceded that the data did not support the primary hypothesis that population sodium excretion would be related directly to population systolic blood pressure. The data also failed to support the secondary hypothesis that sodium excretion would be related directly to diastolic blood pressure. The original Intersalt proposal was limited to those hypotheses. Added later was a second secondary hypothesis, that older cohorts would have higher blood pressures, implying a “rise with age.” It took eight years before the authors conceded that that relationship was created by the statistically-controversial means of driving all the points through zero. Experts, including but not limited to the Salt Institute, noted these contortions. In the original data, when the four primitive populations were excluded, the data actually showed a statistically-insignificant inverse relationship of BP and sodium excretion. That is why the original authors made a couple rounds of further adjustments to their analytic models – to overcome the “failure” of the data themselves to sustain their favored policy outcome.

The proponents of Intersalt were clearly dissatisfied with the outcome of the study, and revised

their initial analysis[1]. In the second rework of the data several more ‘corrections’ were applied for ‘regression dilution bias’ so that stronger, positive correlations emerged between urinary sodium and systolic blood pressure. Again, the scientific basis of this revised analysis was criticized[2] but the recent submission by WASH does not mention this second criticism at all, preferring to leave the impression that only the Salt Institute questioned the value of the Intersalt study and its reanalysis. The WASH comments also omitted to state that the approach to the revision analysis, was considered by some to be openly partial and designed to demonstrate a preconceived correlation[3].

Robertson[4] writes that the publication of the revised INTERSALT analysis was followed by a strange occurrence. Both critics and supporters of the re-analysis were forced to wait for more than a year before their letters were published[5] (British Medical Journal 1997). According to the editors this long delay was the result of undefined ‘problems with the letters’. Only then were Davey Smith & Phillips[6] able to point out that the response by Dyer et al.[7] (1996) to their earlier criticisms (1996) was inadequate and failed to address the substantive points.

Again, the WASH comments appear to be mute when it comes to publications critical to the Intersalt studies and consequent analyses, preferring to subjectively cite only those papers that strengthen their case.

The WASH interpretation of the Dash-Sodium trial is another example of a skewed interpretation resulting from a singular commitment to salt reduction. What the DASH-Sodium[8] trial actually showed was that salt reduction has a minimal impact on blood pressure compared to eating a DASH diet. When reviewing the results on the DASH-Sodium graph, it is immediately apparent that moving from a regular U.S. diet to a DASH-type diet has a far greater impact on blood pressure than lowering salt consumption. On the regular diet, dropping from the current level of sodium consumption to the recommended daily level of 2,300mg Sodium/day dropped the systolic pressure by an average of 2.1 mm Hg (mercury). However, changing from a regular U.S. diet to the DASH diet, without any changes to sodium consumption, reduced the systolic blood pressure by 5.9 mm Hg, almost three times the drop resulting from the sodium reduction! There is no equivalency here. Eating the DASH diet alone had a 3-fold greater effect than not eating the DASH diet and reducing salt consumption by 1/3 down to 2,300 mg/day. This clearly explains why Mediterranean people enjoy an excellent cardiovascular status despite their very high salt consumption. Because of the employment of blood pressure measurements as a proxy for actual health outcomes, the DASH-Sodium trial did not show the negative impact of salt reduction on any other aspect of health such as stiffening of the arteries of young health adults who are limited to 2,300 mg/day sodium[9].

On page 34 of their comments, WASH refers to the case of Finland which has reduced its salt intake by 40% over the last 30 years. They quote the paper by Karpannen and Mervaala[10] which describes a major reduction in CHD and stroke death rates during the same period. This paper has considerable significance. For the first time, it describes an actual example of a nationwide reduction in salt consumption - something no other country has been able to accomplish until now and giving the world a real baseline from which to make judgments regarding the benefits of national salt reduction programs. In addition, the study highlights actual endpoint health impacts, i.e. cardiovascular disease incidence, stroke and life expectancy, to evaluate the benefits of the national salt reduction program. These health outcomes overcome the deficiency of relying solely on blood pressure as a proxy for all health outcomes.

Unfortunately, Karpannen and Mervaala did not compare the Finnish health figures with any other country. When that comparison for CHD and stroke death rates is carried out using the public WHO Global Cardiovascular Infobase, it turns out that Finland did not fare nearly as well as all their neighbors or Canada or the US,[11] countries that did not reduce salt during that same 30-year time period. It is easy to project a case when only one data point is selected, but it has no meaning unless compared to other points. What the Karpannen and Mervaala paper clearly demonstrated when Finland was compared to other countries was that despite a 40% reduction in the consumption of salt in Finland, there were absolutely no health benefits at all attributable to this intervention.

Finally, there is a statement made by WASH which, more than any other, reflects their attitude. It appears on page 37 - “The reasons that the food industry adds salt in such large amounts to processed foods is mainly because it makes cheap, unpalatable food edible at no cost.” The authors pretend to know something about the food industry. It is no different than street car driver saying that “The reason why people with limited intellect go into medicine is to make money.” In both cases the statements are based upon a absence of knowledge rather than an abundance of it and a clear reflection of the lack of devotion to a comprehensive understanding of the issues.

In sum, the Salt Institute believes that the FDA should have available to it the most comprehensive scientific database upon which to make its evaluation and put its efforts squarely behind objective research which emphasizes overall dietary quality while affirming the GRAS status of salt and resisting efforts to trivialize our approach to better health.

[1] Elliott P., Stamler J., Nichols R., Dyer A.R., Stamler R., Kesteloot H. & Marmot M., (1996), “Intersalt revisited: further analyses of 24 hour urinary sodium excretion and blood pressure within and across populations,” British Medical Journal, 312, 1249–1253.

[2] Davey Smith G. & Phillips A.N., (1996), “Inflation in epidemiology: ‘the proof and measurement of the association between two things’ revisited,” British Medical Journal, 312, 1659–1661.

[3] Taubes G., (1998), “The (political) science of salt,” Science, 281, 898–907.

[4] Robertson, J. I. S., (2003), “Dietary salt and hypertension: a scientific issue or a matter of faith?” Journal of Evaluation in Clinical Practice, 9, 1, 1–22

[5] British Medical Journal, (1997), 315, 23 August, passim.

[6] Davey Smith G. & Phillips A.N., (1997), “Correction for regression dilution bias in INTERSALT study was misleading,” British Medical Journal 315, 485–486.

[7] Dyer A.R., Elliott P., Marmot M., Kesteloot H., Stamler R. & Stamler J., (1996), “Commentary: strength and importance of the relation of dietary salt to blood pressure,” British Medical Journal, 312, 1661–1664.

[8] Sacks FM, Svetkey LP, Vollmer WM, Appel LJ, Bray GA, Harsha D, Obarzanek E, Conlin PR, Miller ER, 3rd, Simons-Morton DG, Karanja N, Lin PH., (2001), “Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet,” DASH-Sodium Collaborative Research Group, N Engl J Med,344, 3-10.

[9] Shapiro Y, Boaz M, Matas Z, Fux A, Shargorodsky M., (2008), “The association between the renin-angiotensin-aldosterone system and arterial stiffness in young healthy subjects,” Clin Endocrinol (Oxf), 4, 510-2.

[10] Karppanen H, Mervaala E., (2006), “Sodium intake and hypertension,” Prog Cardiovasc Dis, 49, 59-75.

[11] Satin, M., (2007), “Health Outcomes Lessons from Finland’s Salt Reduction,” Salt and Health Newsletter, 2(3).