Registered Dietitian, PNDS.
Sodium is almost certainly the most extensively studied nutrient influencing blood pressure. Evidence from a variety of sources, including epidemiologic studies as well as intervention trials, indicates rather conclusively at this point that sodium contributes to blood pressure elevations on a population and individual basis1, 2.Therefore salt restriction in the diet is the first line of advice given to hypertensive patients because dietary salt is the main source sodium in our diet as one teaspoon of salt provides 2300mg of sodium3. It is now recommended to restrict sodium intake to 1500mg to a maximum of 2400mg4. Adherence to a low sodium diet is difficult for most individuals therefore nowadays people are opting for salt substitutes in order to reduce sodium intake. Salt substitutes, which replace some or all of the sodium with potassium or calcium, may serve as a useful aid to patients struggling to adjust to a salt-restricted diet. But the question is: “Are these salt substitutes safe?” Rite, No-salt, Lo-salt etc are among the most common salt substitutes available. They contain high percentage of potassium chloride (up to 65-70%). Using a salt substitute that contains potassium has the advantage of reducing sodium intake and increasing potassium intake. Clinical trial outcomes suggest a favorable influence on blood pressure of salt substitution 5, 6. An additional advantage is more palatable diets and better compliance. But in some cases excess potassium can be harmful. Excessive intake of potassium chloride (> 280mmol or 10906mg) can cause acute hyperkalemia and associated problems such as heart failure and cardiac arrest. Potassium containing salt substitutes should be avoided by people taking ACE inhibitors and potassium- sparing diuretics. Chronic use of potassium chloride at levels in excess of 3700mg/day (95mmol/day) may cause gastrointestinal irritation resulting in nausea, vomiting and ulceration7,8 . A number of cases have been reported with cardiac arrest due to hyperkalemia in patients with renal insufficiency taking salt substitutes (Lo-salt) which contain two third potassium chloride9.Case studies of toxicity resulting from high doses of salt substitutes have also been reported and described chest tightness, nausea and vomiting, diarrhea, hyperkalemia, shortness of breath and heart failure10. In conclusion, we can say that although salt substitutes have shown to have a favorable influence on blood pressure, they need to be used with caution in older people, infants, individuals with pre-existing renal- disease, hyperkalemia, adrenal insufficiency, acidosis, insulin deficiency or taking medications which may decrease the body’s excretion of potassium8. Hence salt substitutes should not be used without consulting the health care provider.