Our current lifestyle with its high salt intake poses a problem for us in preventing the damaging effects of excessive salt intake. All of us eat more salt than we need, and almost all of us eat more than is good for our health and wellbeing. Too high an intake of salt raises the blood pressure in many people, especially those past age 50, and those with kidney disease.
The purpose of a sodium-restricted diet is to prevent accumulation of fluid and/or promote a net loss of excess body water. Although sodium reduction is recommended, an aggressive sodium limit of ≤ 1.5 g/day has not demonstrated a mortality benefit and may even increase risk of adverse health effects in some populations.
- Essential hypertension: Blood pressure reduction is correlated with a moderately reduced sodium intake. To decrease blood pressure, the Canadian Hypertension Education Program recommends reducing sodium intake toward 2 g (5 g of salt or 87 mmol of sodium) per day.
- Heart failure: Sodium restriction is the primary diet therapy in treating heart failure. A sodium intake of ≤ 2–3 g/day is recommended for all patients with symptomatic heart failure with a further reduction to ≤ 1–2 g/day for patients with more advanced heart failure or fluid retention.
- Renal disease: Sodium intake should be modified to facilitate blood pressure control, to maintain normal hydration status, and to help prevent heart failure and pulmonary edema. Fluid status and appropriateness of sodium intake can be monitored through measuring blood pressure, interdialytic weight gains, signs of edema and thirst. In people with chronic kidney disease (CKD), sodium reduction lowered blood pressure considerably and reduced proteinuria consistently. However, long-term studies are required to determine the effect on mortality and progression to end-stage kidney disease. Generally, the recommended intake of sodium is 2–3 g per day (87–130 mmol). See our note, "Nutrition for patients with CKD" for more information.
- Liver disease: In patients with liver disease, fluid and electrolyte status must be monitored and sodium restriction may be required.
Choose fresh or frozen food and reduce intake of high-sodium processed food, beverages and condiments (e.g., fast foods, smoked and/or salted meats, canned or prepackaged foods, snack foods, salad dressings). Limit use of salt in cooking and at the table: use salt substitutes (KCl) or other seasoning such as herbs, spices, seasoning blends (e.g., Mrs. Dash), lemon juice and garlic during food preparation. Most salt substitutes contain less than 1 mmol of sodium per teaspoon but large amounts of potassium (30–50 mmol per teaspoon). Patients with renal disease should not use salt substitutes, as ingestion of additional potassium could result in hyperkalemia.
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REMEMBER!
2.4 g elemental sodium = 6 g NaCl = 1 teaspoon of table salt.
| Table (1). Food Containing Sodium | |
|---|---|
| FOOD THAT CONTAIN A LOT OF SALT | FOODS THAT CONTAIN LITTLE SALT |
| Constituents of fast food, especially hamburgers, pizza, Thai and Mexican food Olives in brine, salted nuts Canned beans, corn and peas Potato chips Sauerkraut, tomato ketchup or puree Peanut butter Corn flakes Bread, crackers, donuts, muffins, pies, pretzels, scones Cheese (specially Roquefort, processed cheese, camembert) Bacon, ham, pate, sausages, salami Pickled, smoked or canned fish Sardines |
Fruits and fruit juices Vegetables and salads Unsalted nuts Grains and pasta Eggs, milk, yogurt, ice cream Chocolate Most fresh meats, fish and shellfish Cottage cheese Carbonated drinks and alcoholic beverages |
Advise patients to read the Nutrition Facts table on food packages for sodium content. Sources of sodium include sodium chloride (table salt), celery salt, garlic salt or onion salt, sea salt, baking soda, baking powder, brine for pickling, soy sauce, substances with Na (abbreviation for sodium), monosodium glutamate (Accent or MSG), sodium benzoate, sodium citrate, sodium nitrate, disodium phosphate and sodium gluconate.
- Sodium free/salt free = < 5 mg sodium per serving.
- Very low sodium = ≤ 35 mg sodium per serving.
- Low sodium = ≤ 140 mg sodium per serving.
- Reduced sodium/less sodium = at least 25% less than the regular product.
REFERENCES
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J A Cutler, D Follmann, P S Allender, Randomized trials of sodium reduction: an overview, The American Journal of Clinical Nutrition, Volume 65, Issue 2, February 1997, Pages 643S–651S, https://doi.org/10.1093/ajcn/65.2.643S. Available at: https://academic.oup.com/ajcn/article/65/2/643S/4655388?login=false
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 May 22-29;275(20):1590-7. Available at: https://jamanetwork.com/journals/jama/article-abstract/402918
Daskalopoulou SS, Rabi DM, Zarnke KB, Dasgupta K, Nerenberg K, Cloutier L, Gelfer M, Lamarre-Cliche M, Milot A, Bolli P, McKay DW, Tremblay G, McLean D, Tobe SW, Ruzicka M, Burns KD, Vallée M, Ramesh Prasad GV, Lebel M, Feldman RD, Selby P, Pipe A, Schiffrin EL, McFarlane PA, Oh P, Hegele RA, Khara M, Wilson TW, Brian Penner S, Burgess E, Herman RJ, Bacon SL, Rabkin SW, Gilbert RE, Campbell TS, Grover S, Honos G, Lindsay P, Hill MD, Coutts SB, Gubitz G, Campbell NR, Moe GW, Howlett JG, Boulanger JM, Prebtani A, Larochelle P, Leiter LA, Jones C, Ogilvie RI, Woo V, Kaczorowski J, Trudeau L, Petrella RJ, Hiremath S, Stone JA, Drouin D, Lavoie KL, Hamet P, Fodor G, Grégoire JC, Fournier A, Lewanczuk R, Dresser GK, Sharma M, Reid D, Benoit G, Feber J, Harris KC, Poirier L, Padwal RS. The 2015 Canadian Hypertension Education Program recommendations for blood pressure measurement, diagnosis, assessment of risk, prevention, and treatment of hypertension. Can J Cardiol. 2015 May;31(5):549-68. Available at: https://www.onlinecjc.ca/article/S0828-282X(15)00130-0/fulltext
Arnold JM, Liu P, Demers C, Dorian P, Giannetti N, Haddad H, Heckman GA, Howlett JG, Ignaszewski A, Johnstone DE, Jong P, McKelvie RS, Moe GW, Parker JD, Rao V, Ross HJ, Sequeira EJ, Svendsen AM, Teo K, Tsuyuki RT, White M; Canadian Cardiovascular Society. Canadian Cardiovascular Society consensus conference recommendations on heart failure 2006: diagnosis and management. Can J Cardiol. 2006 Jan;22(1):23-45. Available at: https://www.onlinecjc.ca/article/S0828-282X(06)70237-9/pdf
McMahon EJ, Campbell KL, Bauer JD, Mudge DW. Altered dietary salt intake for people with chronic kidney disease. Cochrane Database Syst Rev. 2015 Feb 18;(2):CD010070. Available at: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD010070.pub2/full
Committee on the Consequences of Sodium Reduction in Populations; Food and Nutrition Board; Board on Population Health and Public Health Practice; Institute of Medicine. Sodium Intake in Populations: Assessment of Evidence. Strom BL, Yaktine AL, Oria M, editors. Washington (DC): National Academies Press (US); 2013 Aug 27. Available at: https://www.nap.edu/catalog/18311/sodium-intake-in-populations-assessment-of-evidence or https://pubmed.ncbi.nlm.nih.gov/24851297