Salt: Shaking out the truth

"You can say without any shadow of a doubt," says Drummond Rennie, a ‘Journal of the American Medical Association’ editor and a physiologist at the ‘University of California’, San Francisco, "that the ‘National Heart, Lung, and Blood’ Institutehas made a commitment to salt education that goes way beyond the scientific facts". (1)

History of salt:

Evidence suggests that homosapiens have an innate desire for the taste of salt. (2)Researchers have demonstrated, that Individuals will subconsciously increase salt intake to rebalance any losses occurred through diuretic treatment. (2)The body does this because if left unbalanced, and sodium levels drop too low (less than 135 mml/L), an individual will enter a mild form of hyponatremia. (3)If internal levels continue to drop, and dive below 130 mml/L, hyponatremia reaches a critical stage with the possibility of coma and death. (3)

This conscious and unconscious craving, coupled with the internal need, has made salt highly prized throughout human history. (4)Salt has been so valued, that the word salary is derived from the Latin word salarium, which has the root meaning of sal better known as salt. (4)

Despite this scientists have been telling us for more than a century now that salt is harming us, that sodium is a ‘blood pressure-raising demon’(5). 

When Salt became a problem:

In 1952, a study was conducted where albino rats were fed a diet of 5% sodium. (6)This study demonstrated a positive correlation between salt consumption and an increase in systolic blood pressure.(6)Then in 1904 the salt–blood pressure hypothesis was formalised by L. Ambard and E. Beaujard who also demonstrated an association between salt consumption and an increase in blood pressure. (7)By the 1970’s a study by L.K. Dhal proved unequivocally that sodium was indeed the cause of high blood pressure. (8)

 By the early 80’s some academics and health authorities were already starting to recommend sodium restriction for cardiovascular health. (9)

Fast forward to 2018, under pressure from the overwhelming body evidence, demonstrating excessive salt consumption is causing a blood pressure epidemic, Governments are being forced to react. (10)

There are groups such as ‘World Action on Salt and Health’ who lobby Governments to reduce salt consumption in their population. Some of the policies implemented on a country wide scale are already causing a decrease in salt consumption. (10)   

However, are Governments rushing to act on science which is still debatable?

….“the results argue against a reduction of dietary sodium as an isolated public health recommendation”. (11)

In 2004, a review of 11 salt-reduction trials by the Cochrane Collaboration showed a long-term low-salt diet would only reduce Systolic and Diastolic blood pressure by around 1 mmol/d for both metrics. (12)They went on to say that these minimal reductions do not justify the intensive interventions needed to reduce salt consumption. (12)

By 2005, the original studies which kicked off the great salt scare were coming into question. (13)It was calculated that in L.K. Dhals study (8)the amount of sodium given to the albino rats would be equivalent to roughly 560 grams per day in a human, this would equate to 50 times more than the average consumption of a person living in the western world. (13)

Then in 2015, A Cross-Sectional Analysis from the NutriNet-Santé Study, a French Web-based Cohort Study found that Body Mass Index (BMI) was the main modifiable factor in reducing Blood Pressure not salt consumption. (14) 

Furthermore, could this rush to reduce salt consumption actually harm us?

A sodium intake and Mortality study conducted in 2006 had 8699 participants which represented over 99 million American adults greater than 30 years of age. (15)They found that lower salt intake had a modest though not significant association with higher mortality. (15)

 However in 2011, a study on diabetic patients called for caution on the push to lower salt consumption. (16)Their study demonstrated low sodium was independently associated with all-cause mortality. (16)

Then Dr. Michael Alderman suggested, researches whoare confident that known beneficial effects of salt reduction will outweigh known negative effects may well be acting rashly. (17)Alderman’s findings suggest that in societies where traditionally salt intake was high there was no association between high salt intake and Cardiovascular Disease (CVD). Whereas lowing salt intake in these populations would increase the risk of CVD. (17)

What we know:

People not only enjoy consuming salt they have a physiological need, when restricted too heavily they will innately search out, and if the internal balance is disrupted too negatively death can result.

Salt can raise blood pressure, though the increase does not appear significant enough to condone drastic salt reduction policies.

Even though it appears salt has been unnecessarily villainised, there is enough anti-salt research to warrant caution, do not shake with abandon until there is undeniable proof, if ever.

In regards to Government policy there should be conclusive proof of mechanism before creating a public policy which could do more harm than good.

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2.         Mattes RD. The taste for salt in humans. Am J Clin Nutr. 1997;65(2 Suppl):692S-7S.

3.         Hew-Butler T, Almond C, Ayus JC, Dugas J, Meeuwisse W, Noakes T, et al. Consensus statement of the 1st International Exercise-Associated Hyponatremia Consensus Development Conference, Cape Town, South Africa 2005. Clin J Sport Med. 2005;15(4):208-13.

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12.       Hooper L, Bartlett C, Davey SG, Ebrahim S. Advice to reduce dietary salt for prevention of cardiovascular disease. Cochrane Database Syst Rev. 2004(1):CD003656.

13.       Graudal N. Commentary: Possible role of salt intake in the development of essential hypertension. International Journal of Epidemiology. 2005;34(5):972-4.

14.       Lelong H, Galan P, Kesse-Guyot E, Fezeu L, Hercberg S, Blacher J. Relationship between nutrition and blood pressure: a cross-sectional analysis from the NutriNet-Sante Study, a French web-based cohort study. Am J Hypertens. 2015;28(3):362-71.

15.       Cohen HW, Hailpern SM, Alderman MH. Sodium intake and mortality follow-up in the Third National Health and Nutrition Examination Survey (NHANES III). J Gen Intern Med. 2008;23(9):1297-302.

16.       Thomas MC, Moran J, Forsblom C, Harjutsalo V, Thorn L, Ahola A, et al. The association between dietary sodium intake, ESRD, and all-cause mortality in patients with type 1 diabetes. Diabetes Care. 2011;34(4):861-6.

17.       Alderman MH. Reducing dietary sodium: the case for caution. JAMA. 2010;303(5):448-9.