The mineral sodium occurs naturally in sodium chloride – or common salt. Humans have added salt to food for thousands of years, both as a preservative and as a flavor enhancer. In modern times, processed, prepared and fast foods add high levels of 'hidden' salt to our diets, with the result that many people today consume too much. High-sodium diets are linked to a number of serious health problems, including high blood pressure, heart disease and kidney failure.
Do not add any form of salt to cooking or at the table. This includes rock salt and sea salt which are very similar to table salt. You may find fairly quickly that your sense of taste adjusts so that you no longer like the taste of salt.
Canned goods are generally high in salt, so try to use fresh, unprocessed food e.g. vegetables, fruit, fish, chicken and meat, which all contain only very small amounts of salt.
Levels of salt and food labelling
Most processed foods are now labelled with the amount of salt that is in the food. Unfortunately, these labels are difficult to understand. Your total daily consumption should be no more than 2gm of sodium per day, which means 5gm of salt. The easiest way to avoid salt is to stick to a couple of rules:
Avoid all foods that have more than 0.2gm of sodium per 100gm. Examples include:
Ideally only eat foods containing less than 0.1gm of sodium per 100gm. There is a HUGE difference between the levels of sodium in fresh and processed foods. Examples include:
Foods with low salt content include:
Foods with high salt content include:
If you have high blood pressure, reducing the level of salt in your diet will reduce your blood pressure. In some people with mild high blood pressure this could free them from blood-pressure-lowering medications entirely. In people with marked high blood pressure, it should mean that a reduction in medications is possible. If you are taking medication for high blood pressure, particularly diuretics, let your doctor know that you are reducing your salt intake.
Salt restriction is recommended for those individuals with hypertension who are "salt-sensitive" or are prone to retaining sodium, gaining weight, and developing a rise in blood pressure as a result of a high-salt diet. Those who are "salt-resistant", on the other hand, do not experience change in weight or blood pressure on either high- or low-salt diets. For the salt-sensitive population, extreme amounts of salt restriction are not needed for improvement of blood pressure. Several studies have shown that diets containing 1600 to 2300mg of sodium per day are associated with average reductions in systolic pressure of -9 to -15mm Hg and in diastolic pressure of -7 to -16mm Hg in salt-sensitive individuals. Thus, salt restriction in this range is recommended in the dietary management of most individuals with hypertension.
Research suggests that people who reduce salt in their diet by about 3gm per day can reduce their chances of developing cardiovascular disease by a quarter.
On average, only 10% of dietary sodium comes from salt added to food at the table. Therefore, beyond eliminating salt from the table, it is recommended that one reduces preserved and processed food consumption and avoids adding excessive salt to food being prepared at home. Ideally, one should try to reduce daily salt intake to 2,400mg (slightly more than 1 tsp). People should check food labels and watch out for high sodium items, including such processed foods as luncheon meats, prepared cheeses, canned vegetables, snack foods and baked products.
Because urinary sodium excretion and urinary calcium excretion occur together in the kidneys, increasing the level of dietary sodium triggers urinary calcium losses [Massey and Whiting, 1996]. According to data from salt-loading trials, when calcium consumption is moderate or high, 500mg of sodium ingested as sodium chloride will draw out about 10mg of calcium. [Institute of Medicine 1997, p. 75; Massey and Whiting, 1996] In other words, sodium leaches calcium from the bones.
If you have IgAN with hypertension or edema, you may be asked to reduce sodium intake. An actual 'renal diet' (low protein, low potassium, low sodium, low phosphorus, high calories) is not required until IgAN has progressed to more advanced renal failure. The purpose of such a renal diet is not to delay progression of IgAN, but mainly to minimize the uremic symptoms of chronic renal failure.
Studies suggest that high salt intake may have an adverse effect on asthma, particularly in men. In a small, preliminary trial, doubling salt intake for one month led to a small increase in airway reactivity (indicating a worsening of asthma) in men with asthma, as well as in non-asthmatics. [BMJ 1988;297:454] At least four double-blind trials have provided limited evidence of clinical improvement following a period of sodium restriction. It is difficult to compare the results of these studies because they used different amounts of sodium restriction. However, they consistently suggest that increased dietary sodium may aggravate asthma symptoms, especially in men. [Clin Exp Allergy 2000;30: pp.615-27]