How much salt should we consume

What is the recommended daily sodium intake?

Pawel Malczewski
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Short Summary

The scientific world is divided into two contradictory positions about how much sodium we should be having per day.

Mainstream opinion, shared by most world governmental and health organizations, uses the established guidelines, indicating a range between 920mg-2,300mg of sodium per day, with a preference to reduce the intake to around or below 1,500mg per day.

New research, however, indicates that a range between 2,645mg–4,945mg of sodium per day is the healthiest and that the lower, “mainstream recommendations” are detrimental to health.

This, unfortunately, leaves us with many questions and no clear answer:

  1. Should we follow the mainstream guidelines of less than 2,300mg of sodium per day?
  2. Can we drop the daily sodium intake even further to below 1,500mg or is this amount dangerous for our health?
  3. Should we have between 2,645mg and 4,945mg as an optimal range contrary to the mainstream guidelines?

Until clear evidence emerges, I would suggest that we should avoid the extreme intakes (whether low or high) and consider the safest, more moderate approach. (See conclusion at the end of this article). For a quick answer click here.

Explanation

Background information and some statistics for better understanding sodium intake issues:

It has long been established and uniformly agreed that:

  1. High blood pressure increases the risk of heart attacks and strokes;
  2. Higher intake of salt causes an increase in blood pressure.

What the studies on this subject do not agree on or do not show clearly is the correlation between salt intake and stroke or death caused by cardiovascular complications. More studies are necessary to resolve this issue.

We currently consume an average of 3,400mg of sodium per day (read more):

  1. 75% of it comes from processed foods,
  2. 12% occurs naturally in food and
  3. 13% we add at the table for extra taste.

Global consumption (from a study with 66 countries) was estimated to be between 2,180mg and 5,510mg of sodium per day. (1)Mozaffarian D, Fahimi S, Singh GM, Micha R, Shahab RM, Engell RE, et al. Global Sodium Consumption and Death from Cardiovascular Causes. N Engl J Med 2014; 371:624-634. Available here.

Please note that, 1 gram of salt has approximately 400mg of sodium.

Mainstream view point on sodium intake

If you are not an athlete who requires more sodium, or suffer from a specific condition in which sodium intake must be limited, according to most governmental and health organizations (see table below) you should be consuming between an “adequate intake” amount of 920mg of sodium and the upper safe limit of 2,300mg daily, preferably being reduced to 1,500mg or below for optimal benefit.

Here are the results of some major studies regarding this subject

  1. A large systematic review and meta-analysis study has shown various health benefits of sodium reduction: a high quality evidence that blood pressure gets reduced; moderate quality evidence that there is no negative impact on blood lipids, catecholamine levels or renal function and that there is an association of lower sodium with the reduced risk of stroke and fatal coronary heart disease in adults. (2)Aburto NJ, Ziolkovska I, Hooper L, Elliott P, Cappuccino FP, Meerpohl JJ, et al. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ 2013;346:f1326. Available here.
  2. A large study by INTERSALT demonstrated a modest increase in blood pressure with higher sodium intake. (3)Stamler J. The INTERSALT Study: background, methods, findings, and implication. Am J Clin Nutr February 1997. vol. 65 no. 2 626S-642S. Available here.
  3. A study that included 18 countries showed that the blood pressure was higher in those people who were ingesting more than 6,000mg of sodium per day, modest between 3,000mg and 5,000mg and insignificant for those that ingested less than 3,000mg per day. (4)Mente A, O’Donnell MJ, Rangarajan S, McQueen MJ, Poirier P, Wielgosz A, et al. Association of Urinary Sodium and Potassium Excretion with Blood Pressure. N Engl J Med 2014; 371:601-611. Available here.
  4. A long term Cochrane systematic review recommends that a reduction from 9g-12g to 5g-6g of salt per day will drastically reduce the blood pressure and that reduction to 3g of salt per day guarantees an optimum blood pressure. Reductions of 5.39 mm Hg for systolic pressure and 2.82 mm Hg for diastolic were observed. Read more about blood pressure ranges here. (5)He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ 2013; 346. Available here.
  5. Meta-analysis of randomised trials showed that a reduction of sodium and an increase in potassium intake in people with hypertension resulted in a blood pressure decrease. (6)Geleijnse JM, Kok FJ, Grobbee DE. Blood pressure response to changes in sodium and potassium intake: a metaregression analysis of randomised trials. Journal of Human Hypertension (2003) 17, 471–480. Available here.

Emerging of new evidence that low sodium intake is dangerous

In the last decade, new studies have been attempting to show that the mainstream recommendations of sodium intake do more harm than good to our health.

These studies claim that there is not enough evidence that sodium amounts consumed at a current intake rate of 3,400mg per day are harmful. They present results showing that the healthiest range of sodium intake is actually between 2,600mg and 5,000mg per day (much more than current mainstream recommendations).

The authors of the above study argue that these conclusions are consistent with the recent discoveries in neuroscience which show that our bodies (in particular, neural circuits in animals’ vertebrae) regulate sodium appetite within the narrow physiologic range.

In other words, the amount of sodium we consume on average per day is what our body needs and therefore the amounts we currently consume are correct.

This, however, in my opinion is not valid reasoning since we have a tendency to develop a taste for salt, meaning that by getting accustomed to processed foods we artificially increase the salt intake.
If our diets consisted mostly of whole foods,  it is possible that our taste for salt would drop naturally and salt added at the table would make up for what our bodies need.

The following studies show contradictory results to the mainstream guidelines, some of which are accompanied with the published peer criticism.

  1. According to the American Diabetic Association lowering the intake of sodium increases the risk of all-cause and cardiovascular mortality in type 1 and type 2 diabetics and patients with an end-stage renal disease (ESRD). (7)Ekinci EI, Clarke S, Thomas MC, Moran JL, Cheong K, et al. Dietary Salt Intake and Mortality in Patients With Type 2 Diabetes. Published online before printFebruary 2, 2011. Available here. (8)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. Published online before printFebruary 9, 2011, Available here.
  2. A recent survey showed that a lower sodium intake (<2,300mg per day) is related to an increased risk of mortality related to cardiovascular diseases. (9)Cohen HW, Hailpern SM, Fang J, Alderman MH. Sodium intake and mortality in the NHANES II follow-up study.. Am J Med. 2006 Mar;119(3):275.e7-14. Available here. (10)Alderman MH, Cohen H, Madhavan S. Dietary sodium intake and mortality: the National Health and Nutrition Examination Survey (NHANES I). Volume 351, No. 9105, p781–785, 14 March 1998. Available here.
  3. A recent cohort study has shown that a lower intake of sodium is associated with a higher risk of cardiovascular related mortality (11)Stolarz-Skrzypek K, Kuznetsova T, Thijs L, Tikhonoff V, Seidlerova J, et al. Fatal and Nonfatal Outcomes, Incidence of Hypertension, and Blood Pressure Changes in Relation to Urinary Sodium Excretion. JAMA. 2011;305(17):1777-1785. Available here.
    However, the study was heavily criticised for its methodological flaws. (12)Campbell NR, Cappuccio FP, Tobe SW. Unnecessary Controversy Regarding Dietary Sodium: A Lot About a Little. Canadian Journal of Cardiology 27 (2011) 404-406. Available here. (13)Campbell N, Correa-Rotter R, Neal B, Cappuccio FP. New evidence relating to the health impact of reducing salt intake. Nutr Metab Cardiovasc Dis. 2011 Sep;21(9):617-9. Available here. (14)He FJ, Appel LJ, Cappuccio FP, de Wardener HE, MacGregor GA. Does reducing salt intake increase cardiovascular mortality? Kidney International. Volume: 80 Issue: 7 Pages: 696-698. Available here.
    One of the criticised methods was that the sodium measurement used excreted urine over 24 hours which is not an accurate measurement (e.g. over 3 days gives more precise results). (15)Schachter J, Harper H, Radin ME, Caggiula AW, McDonald RH, Diven WF. Comparison of Sodium and Potassium Intake with Excretion. Available here.

  4. Another study claims that the current mainstream recommendations are associated with an increased risk of cardiovascular related mortality and hospitalisation. The study showed that the risk of death due to cardiovascular complications increases if the sodium excreted via urine is not within the range of 4,000mg and 6,000mg per day. The excretion of more than 7,000mg of sodium per day showed an increase of risk of death by 1.15 times and the excretion of less than 3,000mg per day showed an increase of 1.27. Excreted sodium in urine is approximately equivalent to ingested sodium, although there are more precise results if the measurement is done over 72 hours rather than 24 as in the case of this study which was one of the reasons it was criticised by peers. (16)O’Donnel MJ, Yusuf S, Mente A, Gao P, Mann JF, et al. Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events. JAMA. 2011;306(20):2229-2238. Available here. (17)Anderson C. A critical appraisal of the ‘Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events’ study cohort, JAMA 2011;306:2229-2238. Available here.
  5. Measurements across 66 countries and using 205 studies, have shown that the lowest risk for mortality from cardiovascular complications occurs when the consumption of sodium is between 3,000mg and 6,000mg daily. An intake of more than 6,000mg or less than 3,000mg was associated with an increased risk. (18)Mozaffarian D, Fahimi S, Singh GM, Micha R, Shahab RM, Engell RE, et al. Global Sodium Consumption and Death from Cardiovascular Causes. N Engl J Med 2014; 371:624-634. Available here.
  6. A study showing that a low sodium diet significantly increases the rate of cardiovascular complications and death due to heart failure. (19)DiNicolantonio JJ, Pasquale PD, Taylor RS, Hackam DG. Low sodium versus normal sodium diets in systolic heart failure: systematic review and meta-analysis. Heart doi:10.1136/heartjnl-2012-302337. Available here.
    These studies, however, have been criticised for their apparent flaws and some were retracted due to missing data (20)DiNicolantonio JJ, Pasquale PD, Taylor RS, Hackam DG. Retraction. Heart 2013;99:820 doi:10.1136/heartjnl-2012-302337ret. Available here. (21)Heart pulls sodium meta-analysis over duplicated, and now missing, data. Available here.

Here are other related readings:

The following table shows a summary of recommendations from various sources:

Ranges of sodiummg per daySources
Minimum limit200-500 Studies (22)Holbrook JT, Patterson KY, Bodner KY, Douglas LW, Veillon C, Kelsay JL, et al. Sodium and potassium intake and balance in adults consuming self-selected diets. Am J Clin Nutr October 1984. Vol. 40 no. 4 786-793. Available here. (23)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. Available here.
Adequate intake460-920NHMRC
Upper Limit for people in a risk group (70% of U.S. population): (24)Centers for disease control and prevention. Application of Lower Sodium Intake Recommendations to Adults --- United States, 1999--2006. Available here.
- People 40 years old or over,
- African Americans,
- People with high blood pressure,
- Diabetics or
- People suffering from chronic kidney disease.

1,500NHMRC , USDA, AND, ADA, AHA
Upper limit2,300NHMRC , USDA, AND, ADA
Upper limit2,400AHA
Upper limit4,945Recent studies (Skrzypek et al)
Ideal daily intake<1,500ADA, AND, AHA
Ideal daily intake2,645–4,945Recent studies
The toxic dietary dose of sodium200mg-400mg per kg of body weight Medicine and Biology (25)Kostic-banovic L, Karadzic R, Antovic A, Petrovic A, Lazarevic M. FATAL POISONING BY EXOGENIC INTAKE OF SODIUM CHLORIDE. Series: Medicine and Biology Vol.12, No 3, 2005, pp. 146 - 149. Available here.
Fatal dose of sodium 400mg-1,200mg per kg of body weightMedicine and Biology (26)Kostic-banovic L, Karadzic R, Antovic A, Petrovic A, Lazarevic M. FATAL POISONING BY EXOGENIC INTAKE OF SODIUM CHLORIDE. Series: Medicine and Biology Vol.12, No 3, 2005, pp. 146 - 149. Available here.
Toxic and fatal levels of sodium intake depend on various factors such as: age, gender, general health state, and other characteristics.
FDA – U.S. Food and Drug Administration (27)U.S. Food and Drug Administration. Lowering Salt in Your Diet. Available here.
USDA – United States Department of Agriculture (28)The national academies press. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. 2005 Available here.
AND – Academy of Nutrition and Dietetics (29)Kojhn J. Combating High Blood Pressure. March 2015. Available here.
ADA – American Diabetes Association (30)American Diabetes Association. Cutting back on sodium. Available here.
AHA – American Heart Association (31)American Heart Association. The American Heart Association’s Diet and Lifestyle Recommendations. Aug 2015. Available here.
NHMRC- National Health and Medical Research Council (Australia and New Zealand) (32)Department of Health and Ageing. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. 2005. Available here.

 

Conclusion

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In light of the new studies and the conflicting results they present, I consider that the following solution for sodium intake is the safest:

  • Eliminate or reduce to a minimum the processed food intake. 
    This will not only cut down on the excessive amounts of salt, but also the other ingredients that adversely affect your health, such as sugar, preservatives and many others.We develop a taste preference for salt. Therefore, the appetite for sodium is higher in people whose diet consists of processed and salty foods. The more salty chips you eat the less sensitive you are to salt and the more sodium you need for the food to taste satisfactory.However, the good news is that by eliminating or substantially reducing the amount of processed foods consumed, you will develop a heightened sensitivity to saltiness within just couple of months, achieving the same pleasure from food as when you were on a high salt diet.
  • Consequently to the above consume mostly whole food.
    Cook more at home using whole ingredients and add salt when you feel you need it. Once the processed foods are cut down and your taste for salt is back to its natural state, your body will tell you if you need more or not. When you get to that stage, you won’t need to make more extreme restrictions.

In addition, if your aim is specifically to reduce blood pressure, see “How to reduce blood pressure”.

References   [ + ]

1. Mozaffarian D, Fahimi S, Singh GM, Micha R, Shahab RM, Engell RE, et al. Global Sodium Consumption and Death from Cardiovascular Causes. N Engl J Med 2014; 371:624-634. Available here.
2. Aburto NJ, Ziolkovska I, Hooper L, Elliott P, Cappuccino FP, Meerpohl JJ, et al. Effect of lower sodium intake on health: systematic review and meta-analyses. BMJ 2013;346:f1326. Available here.
3. Stamler J. The INTERSALT Study: background, methods, findings, and implication. Am J Clin Nutr February 1997. vol. 65 no. 2 626S-642S. Available here.
4. Mente A, O’Donnell MJ, Rangarajan S, McQueen MJ, Poirier P, Wielgosz A, et al. Association of Urinary Sodium and Potassium Excretion with Blood Pressure. N Engl J Med 2014; 371:601-611. Available here.
5. He FJ, Li J, MacGregor GA. Effect of longer term modest salt reduction on blood pressure: Cochrane systematic review and meta-analysis of randomised trials. BMJ 2013; 346. Available here.
6. Geleijnse JM, Kok FJ, Grobbee DE. Blood pressure response to changes in sodium and potassium intake: a metaregression analysis of randomised trials. Journal of Human Hypertension (2003) 17, 471–480. Available here.
7. Ekinci EI, Clarke S, Thomas MC, Moran JL, Cheong K, et al. Dietary Salt Intake and Mortality in Patients With Type 2 Diabetes. Published online before printFebruary 2, 2011. Available here.
8. 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. Published online before printFebruary 9, 2011, Available here.
9. Cohen HW, Hailpern SM, Fang J, Alderman MH. Sodium intake and mortality in the NHANES II follow-up study.. Am J Med. 2006 Mar;119(3):275.e7-14. Available here.
10. Alderman MH, Cohen H, Madhavan S. Dietary sodium intake and mortality: the National Health and Nutrition Examination Survey (NHANES I). Volume 351, No. 9105, p781–785, 14 March 1998. Available here.
11. Stolarz-Skrzypek K, Kuznetsova T, Thijs L, Tikhonoff V, Seidlerova J, et al. Fatal and Nonfatal Outcomes, Incidence of Hypertension, and Blood Pressure Changes in Relation to Urinary Sodium Excretion. JAMA. 2011;305(17):1777-1785. Available here.
12. Campbell NR, Cappuccio FP, Tobe SW. Unnecessary Controversy Regarding Dietary Sodium: A Lot About a Little. Canadian Journal of Cardiology 27 (2011) 404-406. Available here.
13. Campbell N, Correa-Rotter R, Neal B, Cappuccio FP. New evidence relating to the health impact of reducing salt intake. Nutr Metab Cardiovasc Dis. 2011 Sep;21(9):617-9. Available here.
14. He FJ, Appel LJ, Cappuccio FP, de Wardener HE, MacGregor GA. Does reducing salt intake increase cardiovascular mortality? Kidney International. Volume: 80 Issue: 7 Pages: 696-698. Available here.
15. Schachter J, Harper H, Radin ME, Caggiula AW, McDonald RH, Diven WF. Comparison of Sodium and Potassium Intake with Excretion. Available here.
16. O’Donnel MJ, Yusuf S, Mente A, Gao P, Mann JF, et al. Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events. JAMA. 2011;306(20):2229-2238. Available here.
17. Anderson C. A critical appraisal of the ‘Urinary Sodium and Potassium Excretion and Risk of Cardiovascular Events’ study cohort, JAMA 2011;306:2229-2238. Available here.
18. Mozaffarian D, Fahimi S, Singh GM, Micha R, Shahab RM, Engell RE, et al. Global Sodium Consumption and Death from Cardiovascular Causes. N Engl J Med 2014; 371:624-634. Available here.
19. DiNicolantonio JJ, Pasquale PD, Taylor RS, Hackam DG. Low sodium versus normal sodium diets in systolic heart failure: systematic review and meta-analysis. Heart doi:10.1136/heartjnl-2012-302337. Available here.
20. DiNicolantonio JJ, Pasquale PD, Taylor RS, Hackam DG. Retraction. Heart 2013;99:820 doi:10.1136/heartjnl-2012-302337ret. Available here.
21. Heart pulls sodium meta-analysis over duplicated, and now missing, data. Available here.
22. Holbrook JT, Patterson KY, Bodner KY, Douglas LW, Veillon C, Kelsay JL, et al. Sodium and potassium intake and balance in adults consuming self-selected diets. Am J Clin Nutr October 1984. Vol. 40 no. 4 786-793. Available here.
23. 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. Available here.
24. Centers for disease control and prevention. Application of Lower Sodium Intake Recommendations to Adults --- United States, 1999--2006. Available here.
25. Kostic-banovic L, Karadzic R, Antovic A, Petrovic A, Lazarevic M. FATAL POISONING BY EXOGENIC INTAKE OF SODIUM CHLORIDE. Series: Medicine and Biology Vol.12, No 3, 2005, pp. 146 - 149. Available here.
26. Kostic-banovic L, Karadzic R, Antovic A, Petrovic A, Lazarevic M. FATAL POISONING BY EXOGENIC INTAKE OF SODIUM CHLORIDE. Series: Medicine and Biology Vol.12, No 3, 2005, pp. 146 - 149. Available here.
27. U.S. Food and Drug Administration. Lowering Salt in Your Diet. Available here.
28. The national academies press. Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate. 2005 Available here.
29. Kojhn J. Combating High Blood Pressure. March 2015. Available here.
30. American Diabetes Association. Cutting back on sodium. Available here.
31. American Heart Association. The American Heart Association’s Diet and Lifestyle Recommendations. Aug 2015. Available here.
32. Department of Health and Ageing. National Health and Medical Research Council. Nutrient Reference Values for Australia and New Zealand. 2005. Available here.

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