David Ewing Duncan's blog

Killer Salt

Cutting back on the white stuff may save your life, say Harvard Medical School researchers.

David Ewing Duncan 04/20/2007

  • 10 Comments

I'm in London this week, where the front page of the Times of London is carrying a picture of salt and a headline about how salt can kill--as if we need more evidence that sodium-laced processed foods are unhealthy for our hearts. But reading the paper over a typically salty English breakfast made me check my pulse.

Eating 25 to 35 percent less salt reduces a person's chance of a heart attack by 25 percent, and it lowers the risk of premature death by 20 percent, according to a Harvard Medical School study led by researcher Nancy Cook. The 15-year study, published in the British Medical Journal, is the first to defiantly declare salt a health outlaw when overused. It puts to rest claims by the salt industry that its product is safe, and it should blunt the industry's efforts to fight government campaigns here in the United Kingdom and elsewhere that encourage people to cut back.

The Food Standards Agency in the United Kingdom wants to reduce people's daily salt intake from an average of 9.5 grams to 6 grams (that's one-third to one-fifth in quaint American ounces).

As the Times article explains, no one knows for sure why salt causes high blood pressure and increases the risk of stroke, although there's most likely a simple explanation: it involves the inability of the kidney to pass an overabundance of sodium into the urine. Extra salt is then shunted into the blood stream, which sucks up excess water into the blood, increasing volume and pressure.

This adds new meaning to the Old Testament story about Lot fleeing from the destruction of Sodom. God, who was smiting the city, said, "Don't you look back at Sodom, or I'll turn you into salt." Lot dutifully looked ahead, but his wife, Ildith, looked back--and promptly turned into a pillar of sodium. Which is apparently what will happen to me if I keep eating this Sodomic breakfast of salted ham, sausage, and eggs.

From now on I'm going to try to convince my salt-loving tongue to savor the taste of apples, lettuce, and other unsalty foods. My tongue is rebelling, but I'll try to remain resolute. My life, like Lot's, may depend on it.

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dmklass

2 Comments

  • 1761 Days Ago
  • 04/20/2007

The Liver filters salt into the urine now?

I was under the impression that the kidneys, and not the liver, are responsible for filtering salt from the blood stream and into the urine. 

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gabrielg01

450 Comments

  • 1760 Days Ago
  • 04/21/2007

Re: The Liver filters salt into the urine now?

Wow! That's an ugly error indeed. One would think we'd never see this kind of error in TechReview :(( What's next? Lungs for reproduction?:((

PS - a few weeks ago D.E. Duncan was complaining that about 200 million Americans are science illiterate...eewwww...

REPENT David, REPENT!

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davidewingduncan

13 Comments

  • 1760 Days Ago
  • 04/21/2007

Apologies to the kidneys and livers among us!

Oops, my liver, er, my kidney made me do it... I think I was just being dyslexic, since of course it the kidney that processes sodium in the human body, not the liver! Apologies! I'll have the website keepers change this forthwith.

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Guest (rafael7)

  • 1758 Days Ago
  • 04/23/2007

Re: Apologies to the kidneys and livers among us!

Should not be a shocker. See KILLER SALT, by Marietta Whittlesey, 1978/Bolder Books/Avon Books

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gabrielg01

450 Comments

  • 1760 Days Ago
  • 04/21/2007

Blog syndrome

I think mistakes like these are inherent to blogs. Most other publication types go through several layers of filtering and corrections - by the peer review and editorial review. Blogs bypass these systems, and therefore they are far more prone to mistakes. Bloggers should be aware of this.

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Guest (rafael7)

  • 1758 Days Ago
  • 04/23/2007

Re: Blog syndrome

Not only bloggers should be aware... I have noticed an increase in the number of spelling and grammatical errors in all forms of media. Books, newspapers, and magazines are not immune. In our haste to provide a product we rush ideas to print and the 'layers' are apparently circumnavigated with a HEAVY reliance on spellcheckers.

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dmm

270 Comments

  • 1758 Days Ago
  • 04/23/2007

Ildith?

Where did you get the name of Lot's wife?

Getting back on topic: It is interesting how salt was once so valuable that people got paid in salt.  Hence expressions like "worth your salt" and words like "salary."  And the ancient word for salt "sal" has the same root as the ancient word for health "salut."  Too much of a good thing....

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my2cents

1 Comment

  • 1758 Days Ago
  • 04/23/2007

AlsoSalt

I use this stuff.  AlsoSalt is low sodium, salt-free, and actually tastes like salt (no bitter metallic after-taste).  The two main ingredients are  lysine and potassium.  I am surprised that this product is not more well known.

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yeow

1 Comment

  • 1758 Days Ago
  • 04/23/2007

Dehydration kills, Salt is suspect on trial

Duh.... the "Times article explains, no one knows for sure why salt causes high blood pressure and increases the risk of stroke, although there's most likely a simple explanation"

- so we have lots of explainations for all the technology in the world but we don't really understand osmosis very well. - We don't differentiate between a liver and a kidney too well either.

Yes, there is a simple explaination. The concentration of salt is too high. or " it involves the inability of the kidney to pass an overabundance of sodium into the urine"  So theres an overabundance of sodium and theres "excess water" going into the blood. Well if this water is in "excess" then why is it being "sucked into the bloodstream"

so, we blamed the kidney for not being able to remove enough sodium, and we blamed sodium itself.  
next we automatically assume water is in excess because it is in the blood.

So.. perhaps if i drink water so that there is "excess water" perhaps the sodium will be sucked out of the blood by the kidneys because they have water and salt to remove. last time i checked, we   don't pee salt by itelf.

Until we pee salt crystals because we have gallstones we blame our diet, coffee, stress, salty food or the drugs we take before we take responsibility for our own health and drink adequate water.

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rohit

1 Comment

  • 1754 Days Ago
  • 04/27/2007

homeostatic control of ADH in blood pressure

i don't know exactly whether this mechanism is practically sound or not but i think its logically correct.
when water intake decreases - water content of blood decreases - so osmotic pressure of blood increases- this is detected by osmoreceptors in hypothalamus which increases the ADH concentration in circulation - this increases the permeability of DCT and this increases reabsorption of water in tubules and vice versa happens in high water intake.

The concentration of sodium  is regulated by Renin-angiotensin mechanism.The macula densa cells of DCT regulate the sodium  & water concentration iso-osmotically.when the blood presuure falls the hormone renin is secreted by juxtaglomerular cells of kidney which plays an important  role in sodium reabsorption. Renin on reaching blood changes to angiotensinII which activates adrenal cortex to release aldosterone which accelerates reabsorption of sodium and Na and  water enters and leaves together.so loss of sodium causes the loss of water also.angiotensin is an active blood pressure regulator.

all the more body sodium level can lower during diarrhoea or vomiting, diabetes acidosis,severe burns of skin,bactrial infection or inflammation in kidney,starvation or by using diuretic agents.high sodium levels(hypernatremia) occure during dehydration or during cushing syndrome where water intake is nt sufficient 

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