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Mother Nature can handle salt
Salt causes high blood pressure – which ultimately puts you at risk of cardiovascular disease. So we’re often told better body chemistry begins with a low salt diet, but this is not the whole story.
Sodium does cause the blood pressure to rise but mother nature is quite capable of “handling” this rise. A sophisticated regulatory system gets rid of the extra salt and returns blood pressure to normal.
The star player in salt regulation is a hormone called aldosterone.
The “temporary” rise in blood pressure
What happens when you eat a salty meal. The sodium is absorbed into the blood stream making your blood a little more salty.
One of the first concepts they teach you in high school biology is osmosis.
Let me paraphrase the definition ……….water moves from a “high concentration” to a “low concentration” until the “water concentration” is balanced.
The rise in bloodpressure is temporary
So if there is a lot of sodium in the blood, the water concentration has dropped, water will be moving into the blood from the cells to restore the balance. Oh dear ! This causes blood pressure to rise.
The extra water coming into the blood vessels can create a problem because the pipes (blood vessels) have a fixed carrying capacity. Extra water in the pipes has nowhere to go and so the pressure in the system rises.
In most people, the problem is really just temporary because the body carefully regulates the amount of salt.
Sodium is a precious commodity
The “electricity” in your body relies on sodium ions moving in and out of cells. Both your nervous system and your heart depend on bioelectricity to function.
Aldosterone is the chemical tasked with regulating the amount of salt kept by the body so that adequate bioelectricity can be generated.
Aldosterone – working hard
When there is a shortage of sodium, aldosterone has to work hard at keeping the sodium inside your body. It does this by closing the “sodium valves” in the kidney.
The extra sodium means that aldosterone can take a break from controlling the “sodium valves” in the kidney.
Aldosterone – takes a break
As it takes a break, the sodium can slip out of the open valves.
As the extra salt is excreted, water follows (osmosis again), so the volume of blood decreases and the pressure in the pipes returns to normal.
Blood pressure returns to normal……………….
So why the big fuss over salt consumption – it makes food taste good !
Regulation can be disrupted
Now, in some people this regulatory process is “defective” , it is these people, who suffer from salt sensitive hypertension. Everyone else is salt resistant.
So why does it happen ?
It is NOT a fat thing. You can be salt sensitive or salt resistant at any weight.
Genes definitely matter.
There is also some evidence to suggest, salt exposure or lack there of, during development might also contribute to salt sensitivity.
What is your salt sensitivity status ?
Unfortunately there is no inexpensive or easy strategy to identify salt sensitive patients. It boils down to trial & error – you change the amount of salt in your diet and see what happens.
If you are salt sensitive, you can expect to see a big difference of 15 or more mmHg. If you are salt resistant, the difference will be neglibile.
Is it worth knowing ?
Well, if you’ve got high blood pressure – definitely, it gives you a heads up, that you do need to watch your salt intake.
Anti-salt campaigners have got it wrong
But, even if you are salt sensitive, YOU STILL NEED SALT. You need sodium.
If you don’t consume enough, your body makes a plan ! And the plan, includes increased insulin resistance. Which in and of itself is NOT a disease, but it isn’t the recipe for BETTER BODY CHEMISTRY.
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A variety of drugs can be taken to reduce the pressure in the pipes, but many people yearn for non-pharmacological approaches – find out what science suggests.
Salt overloaders / salt addicts, may not be driven by a liking for the taste of salt but by a need to drown out other tastes.