Wayne Turner, of Dunedin, asks :-

Salt is important for the body. Is rock/sea salt any better than iodized salt? Is there any way of knowing your correct salt level without a blood test? Perhaps the old-timers were right in having salt with their porridge.

Kirk Hamilton of the Department of Physiology at the University of Otago, responded.

First, a bit of background. Common salt is composed of sodium and chloride (NaCl). Salt balance in your body is very important and the level of salt is maintained within a narrow range, both inside (10-15 mmoles/litre) and outside of cells (150 mmoles/litre), including blood.

Your body has specials sensors (receptors) that monitor the amount of salt (and water) of your body. If salt levels are too high, then a sequence of physiological changes occur to correct that problem resulting in an increase of salt loss from your body via the urine. Proper levels of sodium are important for a number of processes of your body such as, for example, absorption of food (glucose), electrical nerve activity (action potentials) and contraction of muscles for breathing. So, when the sodium level of the body is altered, this may result in problems. Increase of sodium intake can lead to increased blood pressure which may lead to heart disease and stroke. Some people suggest that high blood pressure is the ‘silent killer’.

Is rock/sea salt better than iodized salt? Rock/sea salt is the product of evaporation of ocean water. This type of salt is not really further processed; therefore, rock salt possesses trace minerals which adds colour, texture and flavour to salt. Before being iodized, natural salt is formed into table salt by super heating at extreme temperatures. Doing this destroys beneficial elements.

Additionally, additives are added to the salt to prevent salt from absorbing moisture which makes it difficult to sprinkle salt from a salt shaker. Table salt is normally fortified with iodine to avoid thyroid problems due to a deficiency in iodine resulting in goitre. When it comes down to the nutritional value of rock salt versus iodized (table) salt, both contain basically the same amount of sodium by weight. However, rock salt does contain trace minerals and elements which have been lost in the processing of table salt.

As for the question ‘Is there any way of knowing your correct salt level without a blood test?’ The simple answer is ‘no’. The typical way to determine someone’s salt level is to have a blood sample taken by a qualified person (doctor or nurse) and have it analysed at a commercial laboratory.

Finally, for those gourmet chefs, you have a real choice of ‘gourmet’ salts to use in cooking. These types of salt include: Table, Sea, Himalayan Pink, Grey, Fleur de sel, Black, Red, Persian Blue, and Smoked. People that have a well-balanced diet will obtain plenty of salt, along with iodine, from their food, enough to fulfil the daily recommended requirements. So, put the salt shaker down.

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