Body salt

[rov1200]

How much does the average male store in body salt? Also if depleted the minimum that could preserve life?

[theprof]

This is a complex question, but I�ll try to answer it as simply as possible. All the same, first of all, we need to clear up a couple of misconceptions.

The first is that you seem to think that there may be a difference between male and female as far as salt is concerned. There isn't. The gender is immaterial.

The second revolves around what happens to salt after we take it into the body. As you probably know, salt is sodium chloride and has the chemical formula NaCl. This means that salt is made up of sodium and chlorine. Now the amount of these two elements in salt is not 50% of each but without boring you with the details, any given weight of salt contains 39.33% of sodium and 60.67% of chlorine by weight.

The body breaks down salt into sodium and chloride ions in the body. Between 25% and 33% of the sodium is sent to the skeleton to act as a reserve. Blood contains about 3.3 grams per litre of sodium in the serum whilst the rest of the body sodium is shared between the fluids between cells, nerve tissue, muscle tissue and a few other locations such as red blood cells.

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[theprof]

What this means is that there is between around 100 grams and 120 grams of sodium in the average human body. Note that this is sodium and NOT salt. In temperate climes, the average human requires around 500 milligrams of sodium to survive. However, the body is capable of dealing with up to 3000mg of sodium daily via excretion through skin and urine without any real adverse effects. Beyond this 3000mg figure, serious illness as a result of poisoning occurs.

We need approximately 500mg of sodium per day in order to survive but there is some variation. The very bottom figure is probably closer to 300mg of sodium per day but this is dependent on biochemical factors that are too complex to discuss here. Furthermore, remember that sodium demand is greater in individuals living in hot climates than in those in temperate climates because they perspire more and get rid of more sodium per day.

If we translated this 500mg of minimum daily amount of sodium into salt, it becomes 1.25 grams of salt. The reality is according to government figures, we consume around 10 grams of salt per day in the UK. This is obviously far in excess of what we need.

[theprof]

Remember also, that not all the sodium in the body comes from salt. Other sources include such things as the sodium bicarbonate contained in food products, sodium citrates in soft drinks and even from tap water.

Ironically, even table salt itself contains more sodium than it should as sodium hexacyanoferrate (ii) (sodium ferrocyanide) is often added to stop salt clumping into a solid mass after packaging.

[rov1200]

Thanks for your very comprehensive answer.