Sodium

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barefoot
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Sodium

Postby barefoot » Wed Sep 17, 2014 2:16 pm

I've been using MyFitnessPal to track my food intake, looking to (and successing in) dropping a few kilos.

As well as energy content and macronutrient balance, MFP also tracks micronutrients where the data is available... sodium in particular. It automatically sets a target to stay under 2300 mg/day.

I haven't modified my diet to do anything about it, but I usually blow that target by a fair margin. Not ridiculously over - but more often over 3000 mg/day than under. But today I'm already up to 3800 mg and I haven't had dinner yet. So I started looking for information on where that 2300 mg number comes from and what the implications are of a diet too high in sodium.

http://www.nrv.gov.au/nutrients/sodium" onclick="window.open(this.href);return false; has lots of the information I was looking for. It seems the main danger is that sodium can increase blood pressure; that's the rationale for setting a recommended maximum intake of 2300 mg... to avoid the likely increase in hypertension.

Now, my blood pressure is good. Just shy of 40, last time I donated blood she clocked me at 115/70, solidly in the "normal" range. In my N=1 case, a higher-than-recommended sodium intake (combined with all other contributing factors) isn't causing me any blood pressure issues.

Am I missing anything? Are there other reasons why I should try to lower my sodium levels?

tim

thecaptn
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Re: Sodium

Postby thecaptn » Wed Sep 17, 2014 5:08 pm

My understanding of salt intake is 3g per day minimum for a sedentary adault male which equates to about 750mg of sodium. As soon as you start exerting yourself the requirement increases significantly, the larger you are and/or if you sweat alot the more you need. If you do alot of regular exersize and sweat a fair bit it's common to suffer inadequate sodium intake which generally results in cramps. Salt gets a bad rap, without it we die and the sports drinks and electrolyte supliments people spend heaps of money on all need to have table salt in them or they wouldn't work. If you have good blood pressure and are generally healthy you probably don't need to worry about it.

iaintas
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Re: Sodium

Postby iaintas » Wed Sep 17, 2014 5:21 pm

Actually low sodium has not been shown to cause cramps, this was studied pretty extensively by the AIS from memory. It will result in nausea, tremors, confusion, seizures and ultimately death.
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Re: Sodium

Postby silentC » Wed Sep 17, 2014 6:01 pm

Was there not also a recent study that failed to find a link between high sodium and hypertension?
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Re: Sodium

Postby thecaptn » Wed Sep 17, 2014 6:18 pm

iaintas wrote:Actually low sodium has not been shown to cause cramps, this was studied pretty extensively by the AIS from memory. It will result in nausea, tremors, confusion, seizures and ultimately death.
Yeah they say that cramps occur due to a lack of water, I'm not convinced, from my own experience, as a big guy who's done lots of physical work, I drink water all day, my clothes go white as the salt crystalises through them. Once I start to cramp all the water in the world wont fix it and could potentially make it worse, half a teaspoon of salt in some warm water and the cramps disappear in under a minute. I imagine that if the AIS did any research it would have been done on young elite athletes who's bodies opperate efficiantly.

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Re: Sodium

Postby Mulger bill » Wed Sep 17, 2014 7:40 pm

iaintas wrote:Actually low sodium has not been shown to cause cramps, this was studied pretty extensively by the AIS from memory. It will result in nausea, tremors, confusion, seizures and ultimately death.
Can I have the cramps instead? :?
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yugyug
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Re: Sodium

Postby yugyug » Wed Sep 17, 2014 8:33 pm

I thought it was potassium that prevented cramps?

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Re: Sodium

Postby iaintas » Wed Sep 17, 2014 8:39 pm

Anecdotal stories are not scientific evidence :P

http://www.ausport.gov.au/ais/nutrition ... and_stitch" onclick="window.open(this.href);return false;
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Re: Sodium

Postby Duck! » Wed Sep 17, 2014 10:52 pm

thecaptn wrote:
iaintas wrote:Actually low sodium has not been shown to cause cramps, this was studied pretty extensively by the AIS from memory. It will result in nausea, tremors, confusion, seizures and ultimately death.
Yeah they say that cramps occur due to a lack of water, I'm not convinced, from my own experience, as a big guy who's done lots of physical work, I drink water all day, my clothes go white as the salt crystalises through them. Once I start to cramp all the water in the world wont fix it and could potentially make it worse, half a teaspoon of salt in some warm water and the cramps disappear in under a minute. I imagine that if the AIS did any research it would have been done on young elite athletes who's bodies opperate efficiantly.
Cramps are caused by lack of electrolytes, of which sodium is only one that's required by the body for proper function. Different electrolytes do different things, but right now I can't remember which does what; one transports water into the cells, others transfer electrical signals from the nerves into the muscle tissues to make them do what they're told. It's the lack of this particular electrolyte that causes cramps; without proper connection, the nerve signals get jumbled, triggering an uncontrolled muscle action - a cramp. That's why drinking stacks of water won't prevent or relieve cramps, and in fact poses additional risks as mentioned previously. You need to get those electrolytes back into your system.
I had a thought, but it got run over as it crossed my mind.

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simonn
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Re: Sodium

Postby simonn » Thu Sep 18, 2014 10:41 am

barefoot wrote:I've been using MyFitnessPal to track my food intake, looking to (and successing in) dropping a few kilos.

As well as energy content and macronutrient balance, MFP also tracks micronutrients where the data is available... sodium in particular. It automatically sets a target to stay under 2300 mg/day.

I haven't modified my diet to do anything about it, but I usually blow that target by a fair margin. Not ridiculously over - but more often over 3000 mg/day than under. But today I'm already up to 3800 mg and I haven't had dinner yet. So I started looking for information on where that 2300 mg number comes from and what the implications are of a diet too high in sodium.

http://www.nrv.gov.au/nutrients/sodium" onclick="window.open(this.href);return false; has lots of the information I was looking for. It seems the main danger is that sodium can increase blood pressure; that's the rationale for setting a recommended maximum intake of 2300 mg... to avoid the likely increase in hypertension.

Now, my blood pressure is good. Just shy of 40, last time I donated blood she clocked me at 115/70, solidly in the "normal" range. In my N=1 case, a higher-than-recommended sodium intake (combined with all other contributing factors) isn't causing me any blood pressure issues.

Am I missing anything? Are there other reasons why I should try to lower my sodium levels?

tim
I am not a dietitian or doctor, but similarly when using MFP, I had similar, but my PT wanted me to keep it lower than 1500mg. What do you eat? If I avoided processed foods it was pretty easy, if somewhat less flavorsome, to do. Just hard when eating any processed foods, particularly bread and quorn. One thing I did notice though is when my son started eating solids we stopped adding salt to everything and after a couple of weeks did not notice.

From my reading of the internet (so take that with... a grain of salt) excess sodium would appear to be a problem only if it is a problem. So if you have reasonable blood pressure etc you are probably ok, but you may have an even better blood pressure if you cut the amount of sodium.

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Re: Sodium

Postby casual_cyclist » Thu Sep 18, 2014 11:59 am

If you are active with normal blood pressure, I don't see a problem at those levels. Here is some interesting (low sodium) food for thought :wink:
A substantial body of evidence supports these efforts to reduce sodium intake. This evidence links excessive dietary sodium to high blood pressure, a surrogate marker for cardiovascular disease (CVD), stroke, and cardiac-related mortality. However, concerns have been raised that a low sodium intake may adversely affect certain risk factors, including blood lipids and insulin resistance, and thus potentially increase risk of heart disease and stroke. In fact, several recent reports have challenged sodium reduction in the population as a strategy to reduce this risk.
http://www.nap.edu/catalog.php?record_i ... pdo-1Ynw.0

Note: you will need to click [read full description] to get the full text
The safest range? Between 2,645 and 4,945 mg of salt a day, the study authors said. And most of the world's populations consume that amount, according to background information in the study.
http://www.webmd.com/food-recipes/news/ ... y-suggests" onclick="window.open(this.href);return false;
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Re: Sodium

Postby moosterbounce » Thu Sep 18, 2014 3:02 pm

I remember stories my parent told me about when they emigrated to Australia in the late 60's and were advised by everyone in the medical profession in the UK to take salt tablets due to the hot climate. Funny.

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barefoot
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Re: Sodium

Postby barefoot » Thu Sep 18, 2014 8:51 pm

simonn wrote:
barefoot wrote:I usually blow that target by a fair margin. Not ridiculously over - but more often over 3000 mg/day than under. But today I'm already up to 3800 mg and I haven't had dinner yet. So I started looking for information on where that 2300 mg number comes from and what the implications are of a diet too high in sodium.
What do you eat? If I avoided processed foods it was pretty easy, if somewhat less flavorsome, to do. Just hard when eating any processed foods, particularly bread and quorn. One thing I did notice though is when my son started eating solids we stopped adding salt to everything and after a couple of weeks did not notice.
It's definitely the pre-packaged processed food that loads me up with sodium. We rarely add salt to home-cooked food.

I generally eat a tin or pouch of pre-made stuff for lunch. The Heinz "Big 'n' Chunky" and Campbells "GO Soup" soups (which are more like stews) are staples... I'm just too lazy to make/bring lunch to work every day, so I keep a draw full of tins. They're not horribly bad for me... the only thing that really stands out is the salt content.

Like the Golden Lentil With Madras Curry Go Soup for example... a 400g package does me for lunch, at 1339kJ; 14g fat, 40g carbs, 8g protein... but 1540mg of sodium. Yikes. More than half my daily "target" in one bowl. That's probably the worst of my regular lunches, but others are near enough. Taste-wise, I'd prefer them to be less salty, but, meh, convenience.

If there was a good reason to cut down on sodium, my lunch-in-a-tin habit would be the first place to start. But if not, then I'll not be worried about it. My reading suggests not, and nobody here seems to have anything to dispute that. So not.

tim

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Re: Sodium

Postby CKinnard » Thu Sep 18, 2014 9:34 pm

Excess sodium leads to calcium losses from bones (when dietary potassium and calcium intake is inadequate)

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barefoot
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Re: Sodium

Postby barefoot » Fri Sep 19, 2014 12:01 pm

CKinnard wrote:Excess sodium leads to calcium losses from bones (when dietary potassium and calcium intake is inadequate)
Thanks - I had noticed that.

Calcium is something I'm mindful of in any case, since having started logging my food on MFP and being surprised by the energy content of milk. I usually drink lots of milk, but now I'm counting...if I'm getting close to my daily energy target and I have a choice between 200 mL of milk or 375 mL of beer, each counting for ~550 kJ... I find I'm drinking less milk than I used to :oops: . So I'm consciously trying to keep my dairy intake up whenever possible. Having slightly higher than recommended sodium is another good reason to do this.

Again, I'm far from a health crisis on this, I'm not about to be diagnosed with osteoporosis and having my teeth fall out, but calcium is a good thing to keep on top of.

tim

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K2
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Re: Sodium

Postby K2 » Mon Sep 22, 2014 1:23 am

moosterbounce wrote:I remember stories my parent told me about when they emigrated to Australia in the late 60's and were advised by everyone in the medical profession in the UK to take salt tablets due to the hot climate. Funny.
Yeah, way to go. As if I wasn't feeling old enough. I actually had to take them. :(

Not nearly as nice as the little coloured fluoride tablets, but not nearly as gag inducing as the milk served in tetra pack tetrahedrons and left to warm in the rapidly rising temperature of a mid-summer morn.

I remember when this was all fields....

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Nikolai
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Re: Sodium

Postby Nikolai » Mon Sep 22, 2014 4:38 pm

Duck! wrote:Cramps are caused by lack of electrolytes
This view doesn't explain how a violin or piano players, who have no lack of electrolytes and don't sweat too much, can still have cramps. Or why only some muscles cramp? The lack of electrolytes is total, is it not? For example, you deprive your body of sodium, and the entire body, not just some muscles, will go into seizures. Why sometimes only one leg cramps? Why do you cramp at night? Lack of electrolytes doesn't explain this.

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Re: Sodium

Postby casual_cyclist » Tue Sep 23, 2014 1:01 pm

Nikolai wrote:
Duck! wrote:Cramps are caused by lack of electrolytes
This view doesn't explain how a violin or piano players, who have no lack of electrolytes and don't sweat too much, can still have cramps. Or why only some muscles cramp? The lack of electrolytes is total, is it not? For example, you deprive your body of sodium, and the entire body, not just some muscles, will go into seizures. Why sometimes only one leg cramps? Why do you cramp at night? Lack of electrolytes doesn't explain this.
Quite correct Nikolai. Here is a quote from a Human Physiology text book:
Muscle Cramps
Involuntary tetanic contraction of skeletal muscles produces
muscle cramps . During cramping, action potentials fire at abnormally
high rates, a much greater rate than occurs during maximal
voluntary contraction. The specific cause of this high activity is
uncertain
, but it is probably related to electrolyte imbalances in
the extracellular fluid surrounding both the muscle and nerve
fibers. These imbalances may arise from overexercise or persistent
dehydration, and they can directly induce action potentials in
motor neurons and muscle fibers. Another theory is that chemical
imbalances within the muscle stimulate sensory receptors in
the muscle, and the motor neurons to the area are activated by
reflex when those signals reach the spinal cord.
Widmaier, Eric P., Raff, Hershel,Strang, Kevin T. (2014) Vander's human physiology :the mechanisms of body function 13th ed. Boston : McGraw-Hill Higher Education.
http://books.google.com.au/books/about/ ... edir_esc=y" onclick="window.open(this.href);return false;

This might explain non-exercise cramps like night cramps but doesn't address exercise related cramps. Bottom line is that:
There is still a lot we don’t know about exercise-induced muscle cramps.
http://blogs.plos.org/obesitypanacea/20 ... salt-loss/" onclick="window.open(this.href);return false;
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Re: Sodium

Postby sogood » Tue Sep 23, 2014 1:12 pm

On cramp: It's but a symptom of body problems, one that can be caused by numerous factors, including electrolyte disturbances, whether K, Ca, Mg or other essential electrolytes. It's multifactorial. Don't narrowly focus on one factor.

On salt: It's a life long issue. Good BP at 40 may mean little in later years. The key is to stay on a healthy lifestyle and diet for decades than expecting quick fixes. Fact is, there are no quick fixes when it comes to chronic diseases and conditions. At the end of the day, YMMV as we are all different and there are more variables than we can humanly control. We can but try to minimise our risks and then keep our fingers crossed.
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Re: Sodium

Postby chriscole » Wed Sep 24, 2014 9:10 pm

sogood wrote:On cramp: It's but a symptom of body problems, one that can be caused by numerous factors, including electrolyte disturbances, whether K, Ca, Mg or other essential electrolytes. It's multifactorial. Don't narrowly focus on one factor.

On salt: It's a life long issue. Good BP at 40 may mean little in later years. The key is to stay on a healthy lifestyle and diet for decades than expecting quick fixes. Fact is, there are no quick fixes when it comes to chronic diseases and conditions. At the end of the day, YMMV as we are all different and there are more variables than we can humanly control. We can but try to minimise our risks and then keep our fingers crossed.

^^^^ What he said. :-)

Regarding cramps, particulalrly, there's no good evidence that it's got much at all to do with any specific electrolyte derangement. There are ideas around the dysfunction of the Golgi tendon organs after prolonged exercise which seem to make better physiologic sense, but high quality evidence is also sparse.

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Sodium

Postby sogood » Wed Sep 24, 2014 9:27 pm

The correlation with electrolytes was largely suggested out of laboratory and clinical neurophysiological experiences where extreme disturbances are seen or dialled in. Trying to elicit its level of contribution in a multi factorial non-clinical setting would be difficult to unrealistic.
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