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Revisiting Sea Salt: Dr. Cordain Responds to a Reader’s Comment

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Revisiting Sea Salt: Dr. Cordain Responds to Reader CommentAs the Paleo movement has grown, many within the community have broadened the original template to include other ingredients that we at ThePaleoDiet.com do not feel should be included as a Paleo staple.  This is not to say that these additions should never be consumed, we have always agreed, that for most people, non-Paleo foods can be included in a healthy diet with an 85:15, Paleo:non-Paleo ratio.  But even if an ingredient can be argued as natural, one should still assess the likely availability, and hence its evolutionary influence upon humans, while also examining the current scientific literature with respect to its affect on human physiology.  Salt, and particularly sea salt, is probably the number one ingredient that is being included in the Paleo template by many in the community, that we feel should not be, at least with regard to the amount.  In my recent post “ThePaleoDiet.com, A New Look with a New Mission.”, I stated that “our new mission at thepaleodiet.com is to address these issues and alternatives through an open dialogue with those that are introducing them.”  Consequently, we encourage comprehensive comments that allow for such a dialogue and some, such as the one by “Anon” to Dr. Cordain’s article “Sea Salt: Between the Devil and the Deep Blue Sea”, warrant a completely new blog post on the topic.  So, without further ado, the comment is below, followed by Dr. Cordain’s response.

Mark J. Smith, Ph.D.

Anon on August 5, 2016 at 9:26 am MDT said:

I would suggest this as a well-argued, comprehensive, counter-point:
http://chriskresser.com/specialreports/salt/

Salt, not a food? Sure; it is indeed a rock. But, all minerals are rocks, and salt is the single mineral that animals in nature seek out to consume directly (salt licks). I think to call it a non-food is to engage in polemics rather than reasoned debate, since that statements and its conclusions are clearly intended to be more provocative than thought-provoking.

Certainly, there is no evidence that paleo humans sought out and consumed large amounts of salt, so I can understand not calling it paleo for that reason. I respect that position. But I have to strongly disagree with the statement:

“There is absolutely no doubt that the average American consumes excessive amounts of salt which in turn may adversely affect health and well being.”

Surely, more than a single citation is required to truly substantiate such a cut and dry claim. All we know for sure is how much salt (and/or sodium) americans are eating now, and we have some reasonable estimates for what was traditionally consumed in the diets of prehistoric humans.

But isn’t that the whole basis of the Paleo diet? Yes, and it too is unsubstantiated scientifically. But, I would further argue that it would be difficult or impossible to substantiate it in principle because reductionism is incapable of appreciating the nearly infinite interdependencies and reciprocal relationships involved. Because of that, and because the overarching Paleo paradigm is one that seems so fundamentally valid, I am willing to make the logical jump from association to causation, more as a bet and a belief than as a fact. Paleo makes sense, in its fundamental concepts and foundations and I believe the totality of that paradigm should be beneficial.

I cannot extend the same kind of leniency to specific claims, such as the health claims and disease relationships being made here about salt. For one thing, the whole issue is confounded from the get go: are we talking about the health effects salt in its natural form (sea salt), or of salt in its pure form (NaCl), or are we talking about sodium in general? One thing that is clear from the science is that sodium’s role and effects in the body are tightly connected to available levels of potassium, calcium, and many other minerals. Simply by not distinguishing between added sodium (processed food) and added salt (in recipes, at the table, to taste) could have large implications for the validity of the data. While some mention is made here of other minerals, the fundamental supposition that dietary sodium intake CAUSES health issues is accepted as fact out of hand. This may be part of the contemporary nutritional gospel, but that doesn’t make it true.

The evidence itself linking salt/sodium (to my knowledge, even the best studies have failed to very tightly control for and examine the distinctions between the two) is shaky and inconsistent at best, and the “totality of the evidence” as so many like to resort to, is really just a way to ignore the studies that have seemed to refute the hypothesized causal links or reconcile them with the established view. But the established view itself was already established long before there was real data to support it:
http://garytaubes.com/wp-content/uploads/2011/08/science-political-science-of-salt.pdf

So, I would argue that associations between salt intake and health issues are not enough to condemn salt specifically.

In any case, many of the other points made by article are valid and helpful: sea salt shouldn’t be automatically assumed to be healthy, for example. Outside of trying to specifically attribute specific disease causes to sodium in general, or NaCl in particular, I think the demonstrated cellular effects are interesting and worth consideration, as they support the view that adding high salt/sodium could upset or change the milieu intérieur and that could have a whole host of undesirable effects and consequences. Let’s just not confuse that with anything close to a known, substantiated, direct causal effect.

Personally, I think that Paleo, as a personal choice, can include a spectrum, or many degrees of interpretations and adherences, and choosing whether or not to include salt is something I would include as a discretionary item, along with dairy. Salt may very well not be, strictly speaking, part of “the” Paleo diet, but I think a paleo adherent could make a reasoned case for salting their food to taste. The basic idea of paleo will continue to evolve and branch as people choose to take their own views, sometimes making it more restrictive (raw paleo) or less (primal), but I would suggest that these debates are intra-community debates that have less significance than extra-community debates (those we all continue to have with the heart-healthy whole grains, low fat crowds). But thanks for weighing in on this one and including some useful information so that folks can make more informed choices.


Dear Anon,

Many thanks for sharing your views with me about my blog topic on dietary salt.  Let me respond briefly to your comments:

You state that:

I would suggest this as a well-argued, comprehensive, counter-point:
http://chriskresser.com/specialreports/salt/”.

I would argue the 2013 review article by Kotchen et al. 1 in The New England Journal of Medicine is a more comprehensive analysis of the available data on salt.  The conclusion of this peer-reviewed paper is completely at odds with Chris Kresser’s ultimate recommendation that “I feel that the data supports an intake between 3000 and 7000 milligrams of sodium, or 1.5 to 3.5 teaspoons of salt, per day” 2.

Kresser’s recommended values for sodium intake translate into 7.6 to 17.8 grams of salt per day which is unfounded and not supported by the scientific evidence. In 2005 the U.S. Department of Health and Human Services recommended that adults in the U.S. consume no more than 2300 mg of sodium per day (5.8 grams of salt).  Additionally, people in specific groups (those 51 years of age or older, people with high blood pressure, diabetes, kidney disease and adults of African American ethnicity should consume no more than 1500 mg of sodium per day (3.8 grams of salt) 3.  Other worldwide organizations including The American Heart Association 4, the World Health Organization 5 and the government of England and Wales 5 have made similar recommendations to reduce dietary sodium.

Starting in the early 1970s, Finland implemented population wide initiatives to reduce salt intake 6.  These initiatives resulted in a decline of more than 10 mm HG in both systolic and diastolic blood pressure and a corresponding decrease of 75 to 80 % in the mortality rate from stroke and coronary heart disease (CHD) 6.

Sodium Consumption: The Evolutionary/Anthropological Evidence

The US recommended intake of sodium is 2300 mg per day (5.8 grams of salt) 3, yet the evolutionary and anthropological evidence indicates that sodium and salt intakes may be lower still.  In perhaps the most comprehensive study of hunter-gatherers and non-westernized people worldwide, Denton demonstrated that their average dietary salt intake ranged from 0.6 grams to 2.9 grams or 236 to 1141 mg of daily sodium 7.   These numbers are derived from population wide urinary sodium excretion rates and are considerably lower than the US recommended value of 2300 mg sodium per day, and much lower than the comparatively extremely high values (7.6 to 17.8 grams of daily salt) proposed by Chris Kresser 2.  

Sodium Consumption: Evidence from Contemporary, Non-Processed Foods

Consider Figure 1 below, which demonstrates the sodium content of four contemporary Paleo foods: meat/seafood (n=8), fruit (n=20) and vegetables (n=18).  Note that fresh meat/seafood averages 694 mg of sodium per 1000 kcal, fresh vegetables 764 mg sodium per 1000 kcal and fruit 54 mg of sodium per 1000 kcal.  Accordingly, contemporary “Paleo” diets averaging 55 to 66 % of daily calories (range 2200 to 3000 kcal) from animal foods and the balance from plant foods would produce sodium intakes ranging from 1600 to 2200 mg.  These calculations show that unless salt is added to Paleo foods or unless processed foods containing added salt are consumed, it would be difficult to exceed the U.S. 2300 mg recommendation for daily sodium, and virtually impossible to obtain Chris Kresser’s advised daily intakes (3000 to 7000 mg sodium) 2.  If fruits were primarily consumed in lieu of vegetables for contemporary “Paleo” diets, the range of daily sodium intake would be lower still (900 to 1200 mg) which falls within the values of historically studied fully, non-westernized populations 7.   With contemporary Paleo foods (fresh fruits, vegetables, meats, seafoods, eggs, nuts etc.) and no added salt, you will be obtaining not only sufficient sodium intakes, but also therapeutically lower sodium intakes that are consistent with values that conditioned our species’ genome over millions of years of evolutionary wisdom.   Lowered or no consumption of added, manufactured dietary salt will lessen your risk for hypertension, stroke and cardiovascular disease 1, 8-14, certain cancers 15-17, autoimmune and immune diseases 18-21, as well as multiple diseases involving chronic low level, systemic inflammation 18-23.  I wrote an article last year on salt’s adverse influence on immunity, inflammation and autoimmunity.

Figure 1.  The Sodium Content of Contemporary Paleo Foods and Processed Foods.
Screen Shot 2016-08-22 at 4.21.44 PM

Summary

Currently, Americans consume (on average) 3400 mg of sodium daily (8.5 g of salt) with 77 % of the sodium coming from processed, packaged and fast restaurant foods 24.  The Paleo Diet is not about processed, packaged and fast foods but rather about fresh fruits, fresh vegetables, fresh grass-produced meats, fresh seafood, nuts and free range eggs.  If you consume these foods on a regular basis, it will be difficult or impossible to exceed the U.S. Health and Human Services guidelines of 2300 mg of sodium per day (5.8 grams).  Chris Kresser’s recommended advice for sodium consumption (3000 to 7000 mg Sodium daily; 7.6 to 17.8 grams salt) on contemporary Paleo diets is virtually impossible without eating processed foods or adding salt to contemporary Paleo foods. Because of the significant body of research indicating an increased risk for cardiovascular disease, cancer and autoimmune disease with increased sodium (salt) consumption, I feel it is irresponsible to promote high salt consumption without concrete scientific backing.

References

[1] Kotchen TA, Cowley AW Jr, Frohlich ED. Salt in health and disease–a delicate balance. N Engl J Med. 2013 Mar 28;368(13):1229-37. (http://www.oeaie.org/content/uploads/2014/08/Kotchen2013_Salt-in-Health-and-Disease.pdf)

[2] Kresser C. Shaking Up The Salt Myth: Healthy Salt Recommendations. May 4, 2012. http://chriskresser.com/shaking-up-the-salt-myth-healthy-salt-recommendations/   

[3] Department of Agriculture, Department of Health and Human Services.  Dietary guidelines for Americans, 2010. 7th ed. Washington, DC: Government Printing Office, December 2010.

[4] Whelton PK, Appel LJ, Sacco RL, et al. Sodium, blood pressure and cardiovascular disease: further evidence supporting the American Heart Association sodium reduction recommendations. Circulation 2012;126:2880-9.

[5] Cappuccio FP, Capewell S, Lincoln P, McPherson K. Policy options to reduce population salt intake. BMJ 2011;343: d4995.

[6] Karppanen H, Mervaala E. Sodium intake and hypertension. Prog Cardiovasc Dis 2006;49:59-75.

[7] Denton D.  Salt intake and high blood pressure in man. Primitive peoples, unacculturated societies: with comparisons.  In: The Hunger for Salt, An Anthropological, Physiological and Medical Analysis. Springer-Verlag, New York, 1984, pp. 556-584).

[8] Strazzullo P, D’Elia L, Kandala NB, Cappuccio FP. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJ. 2009 Nov 24;339:b4567. doi: 10.1136/bmj.b4567

[9] Aaron KJ, Sanders PW. Role of dietary salt and potassium intake in cardiovascular health and disease: a review of the evidence.  Mayo Clin Proc. 2013 Sep;88(9):987-95.

[10] He FJ, MacGregor GA. A comprehensive review on salt and health and current experience of worldwide salt reduction programmes. J Hum Hypertens. 2009 Jun;23(6):363-84.

[11] Ando K, Kawarazaki H, Miura K, Matsuura H, Watanabe Y, Yoshita K, Kawamura M, Kusaka M, Kai H, Tsuchihashi T, Kawano Y. [Scientific statement] Report of the Salt Reduction Committee of the Japanese Society of Hypertension(1) Role of salt in hypertension and cardiovascular diseases. Hypertens Res. 2013 Dec;36(12):1009-19.

[12]  Midgley JP, Matthew AG, Greenwood CM, Logan AG. Effect of reduced dietary sodium on blood pressure: a meta-analysis of randomized controlled trials. JAMA 1996;275:1590-7.

  [13] Cutler JA, Follmann D, Allender PS. Randomized trials of sodium reduction: an overview. Am J Clin Nutr 1997;65: Suppl:643S-651S.

[14] Graudal NA, Galløe AM, Garred P. Effects of sodium restriction on blood pressure, renin, aldosterone, catecholamines, cholesterols, and triglyceride: a metaanalysis. JAMA 1998;279:1383-91.

[15] D’Elia L, Rossi G, Ippolito R, Cappuccio FP, Strazzullo P. Habitual salt intake and risk of gastric cancer: a meta-analysis of prospective studies. Clin Nutr. 2012 Aug;31(4):489-98

[16] Ge S, Feng X, Shen L, Wei Z, Zhu Q, Sun J. Association between habitual dietary salt intake and risk of gastric cancer: A systematic review of observational studies.  Gastroenterol Res Pract. 2012;2012:808120. doi: 10.1155/2012/808120. Epub 2012 Oct 22.

[17] Hu J, La Vecchia C, Morrison H, Negri E, Mery L; Canadian Cancer Registries Epidemiology Research Group. Salt, processed meat and the risk of cancer. Eur J Cancer Prev. 2011 Mar;20(2):132-9

[18] Kleinewietfeld M, Manzel A, Titze J, Kvakan H, Yosef N, Linker RA, Muller DN, Hafler DA.  Sodium chloride drives autoimmune disease by the induction of pathogenic TH17 cells. Nature. 2013 Apr 25;496(7446):518-22

[19] Wu C, Yosef N, Thalhamer T, Zhu C, Xiao S, Kishi Y, Regev A, Kuchroo VK. Induction of pathogenic TH17 cells by inducible salt-sensing kinase SGK1. Nature. 2013 Apr 25;496(7446):513-7.

[20] O’Shea JJ, Jones RG. Autoimmunity: Rubbing salt in the wound. Nature. 2013 Apr 25;496(7446):437-9.

[21] van der Meer JW1, Netea MG. A salty taste to autoimmunity. N Engl J Med. 2013 Jun 27;368(26):2520-1.

[22] Yi B, Titze J, Rykova M, Feuerecker M, Vassilieva G, Nichiporuk I, Schelling G, Morukov B, Choukèr A. Effects of dietary salt levels on monocytic cells and immune responses in healthy human subjects: a longitudinal study. Transl Res. 2015 Jul;166(1):103-10

[23] Zhou X1, Zhang L, Ji WJ, Yuan F, Guo ZZ, Pang B, Luo T, Liu X, Zhang WC, Jiang TM, Zhang Z, Li YM. Variation in dietary salt intake induces coordinated dynamics of monocyte subsets and monocyte-platelet aggregates in humans: implications in end organ inflammation.  PLoS One. 2013 Apr 4;8(4):e60332. doi: 10.1371/journal.pone.0060332. Print 2013.

[24] Sodium intake among adults — United States, 2005–2006. MMWR Morb Mortal Wkly Rep 2010;59:746-9.

About Loren Cordain, PhD, Professor Emeritus

Loren Cordain, PhD, Professor EmeritusDr. Loren Cordain is Professor Emeritus of the Department of Health and Exercise Science at Colorado State University in Fort Collins, Colorado. His research emphasis over the past 20 years has focused upon the evolutionary and anthropological basis for diet, health and well being in modern humans. Dr. Cordain’s scientific publications have examined the nutritional characteristics of worldwide hunter-gatherer diets as well as the nutrient composition of wild plant and animal foods consumed by foraging humans. He is the world’s leading expert on Paleolithic diets and has lectured extensively on the Paleolithic nutrition worldwide. Dr. Cordain is the author of six popular bestselling books including The Real Paleo Diet Cookbook, The Paleo Diet, The Paleo Answer, and The Paleo Diet Cookbook, summarizing his research findings.


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