Here is a post I received from another list where salt was mentioned
particularly questioning what tiers there are to salt use. I'd thought you
could have too little (and had said you'd drop dead mowing the lawn on a hot
day- egg on face). The author is an expert researcher on salt and health.

If you want the fittest person on earth to mow your lawn, look no further
than the Yanomama Indians of the remote rainforest of Brazil and Venezuela.
They are the world's most salt free society with an estimated intake of 6
mmol/day and a 24-hour sodium excretion rate of less than 1 mmol (one
millimole).  Most of the 6 mmol is lost in faeces, sweat and lactation,
leaving virtually none for the urine.  Note that in industrial societies
the 24-hour urinary excretion represents about 90% of intake, so for
practical purposes, such as setting the RDI for sodium, the RDI of 40-100
mmol/day refers to the intake as estimated by excretion rate.  When you
talk about intakes you measure them by excretion rates, and you don't
bother to correct for the 10% difference.

You couldn't find a better advertisement for the Paleodiet than the
Yanomama (syn. Yanomamo, Yanomamö), except that admittedly they live in
settlements and grow vegetables to supplement the meat, fruit and
vegetables obtained by hunting and gathering.  Their robust health, superb
fitness and stamina are legendary (see the book 'Yanomamö, the Fierce
People', by anthropologist N A Chagnon, who spent 12 years with them).
Some people assume that a love of salt is natural 'because animals love it
too', but Chagnon records that the Yanomama detest salt when they first
taste it (they don't go for salt licks like the herbivores that develop
sodium deficiency on virtually salt free pasture).   There are about 20
salt free societies and not one of them has ever been offered salt as a
public health measure (note the contrast between regional availability of
sodium and iodine as natural components of the diet).

The learning curve of GPs about salt doesn't move until they begin to
measure intake by 24-hour excretion.  Before that neither the patient nor
the GP have the faintest idea how much salt is being eaten-the blind are
leading the blind.  Some people who have sworn that they neither cooked
with salt nor added it at the table, and have avoided salty foods
religiously and kept no salt in the house, have actually passed over 200
mmol of sodium in a 24 hour urine collection.

Stepwise taste perception of salt requires logarithmic increases in
concentration, and most people assume that the pathophysiological effects
also require log changes, in line with most drugs, where effective dose
changes commonly involve doubling or halving.  It is useful to distinguish
six levels of intake, starting with the Yanomama at 6 mmol/day and
multiplying by 2.5.  Rounding some of the figures this gives the series:
Level 1 6-15 mmol/day
Level 2 16-40 mmol/day
Level 3 40-100 mmol/day
Level 4 100-250 mmol/day
Level 5 250-650 mmol/day
Level 6 650-1600 mmol/day

Level 1 (using the Kempner diet) is the only non-pharmacological treatment
known to reverse some cases of malignant hypertension.  Instead of the
Kempner diet, a more palatable alternative is to take up anthropology, live
with the Yanomama and eat their Paleodiet.
Level 2 is the Paleodiet with more meat and fish than the Yanomama are able
to catch.
Level 3 is the RDI for sodium, intended for the whole population of
Australia
Level 4 is eaten by hapless victims of the status quo. I know salt is hard
to avoid, but so is fat.  Does that mean we must do nothing?  Yes, let's
ignore fat, because we can't even measure the 24-hour intake.
Level 5 is what a patient of mine excreted in the 24 hours after living
away from home on take-away food for a whole weekend (he excreted 578 mmol,
in a collection with normal volume, potassium and creatinine content).
Level 6 is an experimental diet that raised the BP of all volunteers (n=14)
within 3 days.