January 22, 1999
Mr. Joseph A. Levitt
Director
Center for Food Safety and Applied Nutrition
Food and Drug Administration
Room 6815
200 C Street, SW
Washington, DC 20204
Dear Mr. Levitt:
Thank you for affording us a chance to introduce the Salt Institute and our support for effective nutrition labeling. The Salt Institute is the trade association representing all American producers of food grade salt. Our members also produce salt for other purposes such as roadway safety and mobility, chlor-alkali chemical production, animal nutrition, water softening, etc.
Since 1914, we have advocated public policies to enable American consumers to enjoy the benefits of salt. Over that history, two major health issues have had a heavy salt focus: iodine deficiency disorders (IDD) and cardiovascular health. In the 1920s and 1930s, the salt industry led the fight against IDD in this country, overcoming the disfigurement of goiter and the more serious incidence of mental retardation by iodizing salt. And, since the early 1980’s, have supported regulations and, later, legislation, requiring sodium labeling of foodstuffs so that consumers choosing low-sodium diets would have the information necessary for informed purchasing decisions. We are proud of that record and continue in firm support of both policies.
We recognize both the breadth of your responsibilities and your required focus of limited resources – in this case, emphasizing food safety issues. While salt is used by food processors to assure food safety by retarding bacterial growth and for other reasons beyond enhancing palatability, our concerns focus more on the question of safe diets and not safe foods.
For years, we have taken it for granted in this country that our successful salt iodization campaign of 60-70 years ago had ended the threat of IDD. Our focus has been on assisting UNICEF and other international public health agencies in their number one priority for the 1990s (so identified in the 1990 U.N. World Summit on Children): iodizing salt elsewhere in the world. We can report significant success, and UNICEF chief Carol Bellamy has accepted an invitation to review these achievements at a worldwide salt symposium next year. In the U.S., however, there are new concerns that the American diet may be delivering less dietary iodine, particularly to pregnant women. Last Fall, researchers at the CDC published an analysis of the NHANES I and NHANES III data which, among other things, found that about 7% of pregnant American women were below the safe threshold for iodine consumption. While not enough to raise a red flag and warrant any public messages, it has been enough to get CDC to agree to continue its lab analyses for urinary iodine and to make sure that future population surveys collect urinary iodine -- which had, otherwise, been planned to be abandoned for budgetary reasons.
Why has there been an increase in the number of pregnant American women at risk for IDD? At this point, no one knows. But here's an intriguing idea:
Several years ago, I was invited to present to the HHS Nutrition Coordinating Committee on the subject of sodium and hypertension. During the Q&A, one of the HHS agency reps voiced concern that given the relatively lower amount of sodium in the average woman's diet (about 2,700 mg/day), and given the normal bell-shaped distribution of intakes, should the government's campaign to reduce dietary sodium to no more than 2,400 mg/day be successful, the average intake for women would be much lower – in all likelihood below 2,000 mg/day – and the lower end of the bell curve well below that. The focus of that discussion, of course, was on the impact of sodium and blood pressure, including the potential for disturbing metabolic systems by producing a salt blood pressure sensitivity by unintentionally coincidentally reducing other vital mineral intakes, calcium in particular.
What if the pregnant women with IDD-threatening iodine intake levels are also that group of women who have discontinued using their salt shakers – the primary source of iodized salt? We know that use of "round can" consumer salt, including nearly all iodized U.S. salt, has been declining since W.W. II as we eat out more and buy more pre-processed home-cooked or -heated foods which contain non-iodized salt. We have seen evidence that low-sodium dieters make choices that produce deficiency levels of other vital minerals; why not iodine?
So, while these are but fragmentary results and we may not have a reviving problem with iodine, might these CDC analysts have begun to identify a broader problem? Perhaps our diets are not as safe as we had hoped – and assumed. Maybe iodine isn’t the only mineral whose deficiency intake levels should concern us. Perhaps FDA should be paying more attention to CDC and the U.S. Preventive Services Task Force and less to the anti-salt ideologues at NHLBI. I hope you’ve had a chance to read the article in Science by Gary Taubes on "The (Political) Science of Salt" which outlines the efforts by NHLBI to filter the interpretations of the science FDA receives regarding the safety and efficacy of reduced sodium diets. The U.S. Preventive Services Task Force at HHS has examined the evidence on sodium and blood pressure and concluded:
"There is insufficient evidence that, for the general population, reducing dietary sodium intake or increasing dietary intake of iron, beta-carotene, or other antioxidants results in improved health outcomes." (emphasis added)
Yet a general population advisory to reduce dietary sodium is the position underlying the current FDA health claim on "Sodium and Hypertension." I could rehearse with you the science on safety and efficacy in detail, but suffice it to say that: 1) several meta-analyses have been done with relatively similar results (except for the "spin" by their authors) which we feel demonstrate the superiority of a targeted promotion of lower-sodium diets rather than the current promotion of universal sodium restriction, and 2) of the only four studies exploring the health outcomes of lower-sodium diets, two found no discernible benefit – and the other two found significant increased risks. Again, not a "food safety" argument; rather a diet safety issue. On top of that, the NHLBI-funded Trials of Hypertension Prevention, phase II, has documented that any blood pressure-lowering effect of lowering dietary sodium disappears after 18 months – hardly a recipe for a lifetime lifestyle change to enhance health.
Perhaps even more tellingly, NHLBI funded the DASH Study (Dietary Approaches to Stop Hypertension) which found dietary interventions can lead to a dramatic improvement in blood pressure – and then NHLBI has almost completely ignored the policy outcomes that would flow from this seminal work. The DASH Study, you see, was "politically incorrect" inasmuch as it held dietary sodium constant at about 3,000 mg/day, 25% above the DRV, above that consumed by women today and only slightly below the national average intake. The results were that the "DASH Diet," heavy in fruits, vegetables and low-fat dairy products, produced a blood pressure benefit equivalent to drug therapy – unheard of! We think we know why: blood pressure sensitivity to sodium exists where there is a deficiency in other key electrolytes: calcium, potassium and magnesium. Studies in which the protocol reduces dietary sodium have also reduced these other key electrolytes, thus creating salt-sensitivity; they then proceeded, by adding salt back into the diet, to create a blood pressure increase on the higher salt intake.
In the months preceding the resignations of David Kessler, Fred Shank and Ed Scarbrough, the Salt Institute petitioned FDA to rescind the NLEA health claim on "sodium and hypertension," including the disqualifier that other health claims be prohibited on an otherwise-qualifying food that was not "low sodium." We withdrew that petition when it became clear that those who would decide the issue would be brand-new to the issue. With the continued emergence of studies showing that the "significant scientific agreement" that FDA used to justify the claim when it was adopted has evolved into a raging debate among scientific experts in the field, we feel the agency should reconsider the issue. But since the priority has been determined to be "food safety," we anticipate such a renewed petition would have a hard time competing for scarce resources.
Therefore, we recommend that you, Dr. Henney and other FDA officials responsible for the integrity of the FDA nutrition labeling apparatus, invite key hypertension researchers in for a direct briefing so that you might judge whether "significant scientific agreement" sustains the current claim. We would suggest such an invitation be extended to Drs. Michael H. Alderman, Alexander G. Logan, David A. McCarron and Suzanne Oparil.
As Science reporter Gary Taubes concluded:
"After interviews with some 80 researchers, clinicians, and administrators throughout the world, however, it is safe to say that if ever there were a controversy over the interpretation of scientific data, this is it. In fact, the salt controversy may be what Sanford Miller called the ‘number one perfect example of why science is a destabilizing force in public policy." (page 899)
Sandy Miller not only remains an astute and informed observer on these matters, but his perspective should be particularly consequential as you weight this issue. Sandy not only served with distinction as Director of CFSAN, but headed the Center when it first grappled with the salt issue. I think he would confirm my assessment of the role of balanced electrolytic intake.
Repeal of the "sodium and hypertension" health claim need not be seen as a retreat from protection of public health. In fact, it serves as an impediment to advances in our fight to reduce the incidence of stroke and heart attacks by diverting attention and resources from more effective strategies such as vigorously promoting the DASH Diet. The nation would be well-served for FDA to take a leadership position in aligning public health nutrition policy with sound science.
Sincerely,
Richard L. Hanneman
President, Salt Institute