Sandrine Wetzler, a project manager in the nutrivigilance mission of the National Agency for Food, Environmental and Occupational Health Safety (ANSES), has examined salt substitutes, often consumed within specific diets.
In pharmacies and supermarkets alike, substitutes for “table salt” are available for those adhering to a “low-salt diet” for health reasons or looking to reduce their sodium intake in line with recommendations from national authorities and the World Health Organization (WHO).
The WHO estimates that approximately 1.9 million deaths per year globally are linked to excessive sodium consumption. A clear link has been established between high sodium intake and hypertension, a known risk factor for cardiovascular diseases.
Vigilance with Potassium-based Salt Substitutes
The WHO recommends consuming less than 2 g of sodium per day (equivalent to less than 5 g of table salt). Populations with high salt intake sometimes turn to salt substitutes without realizing these products can pose health risks.
These substitutes typically contain potassium chloride. Their consumption may be particularly dangerous for individuals with medical histories including hypertension, heart failure, kidney disease, or diabetes.
In October 2018, a cardiologist alerted ANSES about the risks of excessive potassium (hyperkalemia) in the blood, which can lead to severe or even fatal consequences due to the consumption of potassium chloride.
This refers to potassium chloride used as a substitute for “table salt” (sodium chloride) in the context of a “low-salt diet” (termed hyposodic). ANSES promptly initiated an evaluation to assess the risks associated with these products.
Potassium: An Essential Mineral
Potassium is an essential mineral in our bodies, present in all our cells. It plays a fundamental role in nerve transmission, muscle contraction, and heart function. Additionally, it is involved in insulin secretion, carbohydrate and protein metabolism, and maintaining the body’s acid-base balance.
In its 2021 report updating nutritional references for vitamins and minerals, ANSES recommended a potassium intake of 3,500 mg/day, which benefits blood pressure in adults. It found that lower intakes are associated with a higher risk of stroke. Due to insufficient robust data to ascertain an average nutritional need, a satisfactory intake of 3,500 mg/day was established for both men and women.
In France, average potassium intakes are estimated at 3,484 mg/day for men and 2,755 mg/day for women (ANSES, figures published in 2017), slightly higher among men due to greater food consumption.
It’s important to note that low potassium concentration in the blood (or hypokalemia) resulting from inadequate dietary potassium intake can lead to cramps, fatigue, and urinary disorders, although this is quite rare and usually occurs in cases of extreme caloric restriction or malnutrition.
Clinical Manifestations of Excess Potassium
The primary food groups contributing to potassium intake include starchy foods, cereals, vegetables, and dairy products. Foods like chocolate and bananas are also naturally high in potassium (according to data from the Ciqual nutritional composition table).
Beyond sodium substitutes, potassium chloride is also used in various food products, often related to manufacturing processes (potassium fortification, additives, and technological auxiliaries), without clear labeling for consumers.
For the general healthy population, risks associated with high potassium intake, exceeding nutritional recommendations, seem limited. However, for certain groups, particularly those with impaired renal potassium excretion, consuming too much can lead to dangerously high potassium levels (hyperkalemia), possibly impacting heart function.
Mild to moderate hyperkalemia often presents nonspecifically, manifesting as general weakness, paralysis, nausea, vomiting, and diarrhea.
Severe hyperkalemia (over 6.5 millimoles per liter, or about 254 mg/l) can lead to various clinical signs depending on the cause and the patient’s health status; the most dangerous are heart rhythm disorders that can be fatal. These risks are amplified by dehydration, especially among the elderly.
At-risk Groups: Renal and Cardiac Patients, Diabetics, Hypertensives
The WHO’s international database (Vigilyze), which catalogs all adverse drug effects, has been queried to identify instances of hyperkalemia worldwide since 1986.
Of over 23,000 cases, including around a thousand fatal ones, nearly 3,000 were recorded in France. The majority stemmed from medication-related causes, notably among diabetic (Type 2) patients, heart failure sufferers, and those with kidney issues treated with medications that hinder renal potassium excretion or introduce potassium.
Considering these observations and a body of scientific literature, it is evident that those at highest risk for hyperkalemia from inappropriate use of potassium salts include:
- End-stage renal patients;
- Diabetics;
- Heart failure patients;
- Hypertensive individuals;
- Older adults, who are often treated for hypertension, diabetes, heart failure, or reduced kidney function.
The European Food Safety Authority (EFSA) has also noted some case studies indicating that potassium supplementation of 5,000 to 7,000 mg/day could adversely affect heart function in healthy adults. It identified additional risk situations for individuals engaged in activities leading to dehydration (such as exercise or working in hot conditions).
Labeling and Other Recommendations from ANSES
Individuals presenting one or more risk factors comprise a significant segment of the French population. Consequently, ANSES has recommended that those needing to reduce salt intake or increase potassium consumption be made aware of the risks of hyperkalemia associated with potassium chloride substitutes.
Authorities have been alerted to the dangers consumers face due to insufficient labeling information regarding potassium salts, especially for those receiving inadequate or no medical supervision who possess conditions heightening their risk.
It has been suggested that warnings be added to applicable products, such as:
” Individuals treated for hypertension, diabetes, heart failure, or having diminished kidney function are advised to consume this product only under medical supervision. “
Furthermore, since 2006, ANSES has recommended informing consumers upon purchasing potassium-containing dietary supplements or salt substitutes that these products are contraindicated in cases of kidney failure or low-potassium diets.
ANSES has also raised awareness among authorities about the existence of three authorized health claims under European regulations for potassium, one of which states that “potassium contributes to maintaining normal blood pressure.” This claim could lead hypertensive individuals to seek products containing potassium chloride and thus risk their health.
It is essential to maintain consistent and rigorous medical supervision for at-risk individuals and ensure that consumers are adequately informed about these salt substitutes to significantly reduce the risk of hyperkalemia.