UPDATED!! Time to end the war on Salt?

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UPDATED!! Time to end the war on Salt?

Postby Spiral » Sat Jul 23, 2011 11:43 am

I don't agree with this conclusion, but this journalist for Scientific American says, "Yes."

It's Time to End the War on Salt by Melinda Wenner Moyer
This week a meta-analysis of seven studies involving a total of 6,250 subjects in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure. In May European researchers publishing in the Journal of the American Medical Association reported that the less sodium that study subjects excreted in their urine—an excellent measure of prior consumption—the greater their risk was of dying from heart disease. These findings call into question the common wisdom that excess salt is bad for you, but the evidence linking salt to heart disease has always been tenuous.
I remember Dr. McDougall saying that meta-analysis can be manipulated by cherry picking the studies that are included. Probably the case here.
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Re: Time to end the war on Salt?

Postby JeffN » Sat Jul 23, 2011 11:53 am

Spiral wrote:I remember Dr. McDougall saying that meta-analysis can be manipulated by cherry picking the studies that are included. Probably the case here.


Especially when it is done by the Salt Institute.

The IOM refuted these conclusions.

Remember, most people do not know how to lower salt and so it is rarely shown to be effective. Also, those who are most likely to reduce salt are those who are the sickest and on the most medication, which can lower BP but also increase morbidity and mortality

It was the confounding of their medications. Lowering salt still matters :)

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Salt reduction lowers cardiovascular risk: meta-analysis of outcome trials
Lancet Volume 378, Issue 9789, 30 July 2011-5 August 2011, Pages 380-382
Feng J He, Graham A MacGregor

A recent Cochrane Review by Rod Taylor and colleagues, published simultaneously in The Cochrane Library1 and the American Journal of Hypertension2, stated in the plain language summary that "Cutting down on the amount of salt has no clear benefits in terms of likelihood of dying or experiencing cardiovascular disease".1 The Cochrane Library's own press release headline included this statement: "Cutting down on salt does not reduce your chance of dying".3 Both of these statements are incorrect.

The study reported in the paper by Taylor and colleagues is a meta-analysis of randomised trials with follow-up for at least 6 months on the effect of reducing dietary salt on total mortality and cardiovascular mortality and events.[1] and [2] There were seven trials with 6250 participants (665 deaths). One of these trials in heart failure,4 in our view, should not have been included because the participants were severely salt and water depleted due to aggressive diuretic therapy (frusemide 250-500 mg twice daily, and spironolactone 25 mg per day) as well as captopril 75-150 mg per day and fluid restriction to 1000 mL per day.4 While on these treatments, participants were randomly assigned to a reduced salt intake or their usual salt intake.4 In view of the fact that the dose of diuretics was not adjusted downwards, a lower salt intake is likely to worsen the salt and water depletion and therefore, unsurprisingly, resulted in worse outcomes.

In the remaining six trials, there is a reduction in all clinical outcomes (all-cause mortality, cardiovascular mortality and events) (table), although none of these are statistically significant. This trend of consistent reductions in all clinical outcomes seems to have been overlooked by Taylor and colleagues.1 The non-significant findings are most likely the result of a lack of statistical power, particularly as Taylor and colleagues analysed the trials for hypertensives and normotensives separately. We have reanalysed the data by combining data for hypertensives and normotensives together. Our results show that there is now a significant reduction in cardiovascular events by 20% (p<0·05) (figure) and a non-significant reduction in all-cause mortality (5-7%), despite the small reduction in salt intake of 2·0-2·3 g per day. The results of our reanalysis, contrary to the claims by Taylor and colleagues, support current public health recommendations to reduce salt intake in the whole population.

Table. Change in salt intake, blood pressure, and clinical outcomes with results from the meta-analysis by Taylor and colleagues1 (excluding the trial in heart failure)
-----------------------------------------------------
Trials in normotensives (n=3)* Trials in hypertensives (n=3)*
-----------------------------------------------------
Reduction in salt intake at end of trial (g per day [95% CI]); duration 6-36 months 2·0 (1·1 to 2·9) 2·3 (1·8 to 2·8)
Fall in blood pressure at end of trial (mm Hg [95%CI]); duration 18-36 months
Systolic 1·11 (?0·11 to 2·34) 4·14 (2·43 to 5·84)
Diastolic 0·80 (0·23 to 1·37) 3·74 (?0·93 to 8·41)
Difference in all-cause mortality at longest follow-up (95%CI); duration 7 months to 12·7 years 10% reduction (RR 0·90, 0·58 to 1·40) 4% reduction (RR 0·96, 0·83 to 1·11)
Difference in cardiovascular events at longest follow-up (95%CI); duration 7 months to 11·5 years 29% reduction (RR 0·71, 0·42 to 1·20) 16% reduction (RR 0·84, 0·57 to 1·23)
Difference in CVD mortality at longest follow-up (95%CI); duration 7 months to 6 years - 31% reduction (RR 0·69, 0·45 to 1·05)
-----------------------------------------------------
RR=relative risk; CVD=cardiovascular disease.
* Not all measurements were made in all trials.

Taylor and colleagues call for further large long-term randomised trials of salt reduction on clinical outcomes.[1] and 2 RS Taylor, KE Ashton, T Moxham, L Hooper and S Ebrahim, Reduced dietary salt for the prevention of cardiovascular disease: a meta-analysis of randomized controlled trials (Cochrane Review), Am J Hypertens 24 (2011), pp. 843-853.[2] According to their own calculations, at least 2500 cardiovascular events need to be obtained to detect a 10% reduction (at 80% power and 5% significance level).2 This would require randomisation of about 28 000 participants to a low or high salt intake and then maintenance of the two separate diets for at least 5 years. Such a trial is impractical because of logistical and financial constraints, and the ethical issues of putting a group of people on a high salt diet for so many years.

In our view, Taylor and colleagues' Cochrane review and the accompanying press release reflect poorly on the reputation of The Cochrane Library and the authors. The press release and the paper have seriously misled the press and thereby the public-for example, in the UK the Daily Express front page headline read "Now salt is safe to eat-Health fascists proved wrong after lecturing us all for years"5 and there were similar headlines throughout the world.

The totality of evidence, including epidemiological studies, animal studies, randomised trials, and now outcome studies all show the substantial benefits in reducing the average intake of salt.[6], [7], [8] and [9] Most countries have adopted policies to reduce salt intake by persuading the food industry to reformulate food with less salt, as is occurring successfully in the UK,10 and also by encouraging people to use less salt in their own cooking and at the table. WHO has recommended salt reduction as one of the top three priority actions to tackle the global non-communicable disease crisis.11 A reduction in population salt intake will have major beneficial effects on health along with major cost savings in all countries around the world.[6], [12] and [13]


1. Reduced dietary salt for the prevention of cardiovascular disease.
Taylor RS, Ashton KE, Moxham T, Hooper L, Ebrahim S.
Cochrane Database Syst Rev. 2011 Jul 6;(7):CD009217.
PMID: 21735439
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Re: Time to end the war on Salt?

Postby HealthyMe2010 » Sat Aug 13, 2011 1:44 pm

I read somewhere, I wish I remember where, that salt really isn't the problem, but a lack of adequate potassium was. When potassium was at a reasonable level in the diet, salt intake didn't have an effect (or not as much) on health.

If I find the study, I will post it, but has anyone else read that?
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Re: Time to end the war on Salt?

Postby JeffN » Sat Aug 13, 2011 1:46 pm

HealthyMe2010 wrote:I read somewhere, I wish I remember where, that salt really isn't the problem, but a lack of adequate potassium was. When potassium was at a reasonable level in the diet, salt intake didn't have an effect (or not as much) on health.

If I find the study, I will post it, but has anyone else read that?


It is not either/or but both and both are a result of a diet low in whole plant foods with too much added salt.

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Re: Time to end the war on Salt?

Postby HealthyMe2010 » Sat Aug 13, 2011 1:51 pm

JeffN wrote:
HealthyMe2010 wrote:I read somewhere, I wish I remember where, that salt really isn't the problem, but a lack of adequate potassium was. When potassium was at a reasonable level in the diet, salt intake didn't have an effect (or not as much) on health.

If I find the study, I will post it, but has anyone else read that?


It is not either/or but both and both are a result of a diet low in whole plant foods.

In Health
Jeff


Exactly. The study pointed out that potassium intake for both males and females were below the recommended intake while sodium intake was high. If a balance could be met, the health effects could be minimized.
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Re: Time to end the war on Salt?

Postby Adrienne » Sun Aug 14, 2011 1:34 pm

Jeff do you have any comments on this study from last year that found that low-salt diets increased the risk for insulin resistance in healthy people?

http://www.ncbi.nlm.nih.gov/pubmed/21036373
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Re: Time to end the war on Salt?

Postby JeffN » Sun Aug 14, 2011 1:48 pm

Adrienne wrote:Jeff do you have any comments on this study from last year that found that low-salt diets increased the risk for insulin resistance in healthy people?

http://www.ncbi.nlm.nih.gov/pubmed/21036373


My comments above still apply. This was a 7 day diet and didn't control for all the things I mentioned above.

I wouldn't give too much weight to this study or the more recent meta-analysis that also got a lot of media attention.

In nearly all of the studies in the recent meta-analysis and most other studies the "low-sodium" group is still getting too much sodium sometimes very large amounts. Therefore, it's not surprising that they don't show much benefit or any at all when the "low-sodium" diet isn't low-sodium. It's similar to the studies that show no benefit from lowering saturated fat.

Several of the studies included in the meta-analysis were also on very young populations where outcome events are very rare. Also, a substantial fraction of the participants who died were heavy smokers, and with so few deaths to begin with, it's hard to adjust for that confounding issue.

In addition to the acute effect on BP, sodium also stiffens the blood vessels, and contributes to the progressive stiffening of the blood vessels over time. This effect also doesn't manifest in young people but will show up later in life.

I have often provided a link here to a CEU course of sodium that a colleague wrote. It clearly outlines all the benefits from well done studies, including in the few where they carefully controlled for both diet and sodium intake and the benefit is clear.

Remember, the level of sodium you get from eating a mixture of natural foods is perfectly safe, with or without the small amount of added salt we allow. But the amount of sodium that most people get in from restaurant and processed food, is many, many times that. If you look at the nutrition information available at many chain restaurants you can easily find single meals with two or three times the UL for sodium recommened by the IOM (2300 mg), let alone the Adequate Intake (1200-1500 mg) or less. Even a person who mostly eats homemade food with only occasional restaurant and bought-in-store meals, are bound to get substantially more than they need if they aren't actively monitoring it.

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Re: Time to end the war on Salt?

Postby cbs » Mon Aug 15, 2011 9:36 am

well i guess i wont say too much but i'll agree to disagree on sodium after being diagnosed hyponatremic 3 times over 6 months being strict about this and being told it could kill me. i'll listen to my dr.
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Re: Time to end the war on Salt?

Postby JeffN » Mon Aug 15, 2011 9:45 am

cbs wrote:well i guess i wont say too much but i'll agree to disagree on sodium after being diagnosed hyponatremic 3 times over 6 months being strict about this and being told it could kill me. i'll listen to my dr.


Serum sodium, which is what hyponatremia is based on, is not directly related so dietary sodium intake.

http://www.nlm.nih.gov/medlineplus/ency ... 000394.htm

So, if someone has been diagnosed with hyponatremia several times, there are other issues going on that need to be addressed and if are not being addressed, can lead to bigger issues down the road. .

Causes of hyponatremia include:
Burns
Congestive heart failure
Diarrhea
Diuretic medications, which increase urine output
Kidney diseases
Liver cirrhosis
Syndrome of inappropriate antidiuretic hormone secretion (SIADH)
Vomiting
Cancers

Treatments vary depending on the cause but dietary sodium is not a treatment for hypnoatermia

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Re: Time to end the war on Salt?

Postby RawDad » Thu Sep 01, 2011 6:20 pm

Interesting. Dr. McDougall says in this video we are supposed to eat salt & seek salt......@ ~ 1:15 into the video....

http://www.youtube.com/watch?v=aVtOzORO ... r_embedded

This is a very confusing subject. On this diet I tend to urinate quite frequently... perhaps its a potassium/sodium imbalance ?

One does have to ask... why is it the foremost taste we seek ?
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Re: Time to end the war on Salt?

Postby JeffN » Thu Sep 01, 2011 9:34 pm

RawDad wrote:Interesting. Dr. McDougall says in this video we are supposed to eat salt & seek salt......@ ~ 1:15 into the video....


Human beings require sodium not salt. Salt is a compound molecule that contains sodium.

We get all the sodium we need from what occurs naturally in whole plant foods when someone follows the guidelines and recommendations here.

RawDad wrote:why is it the foremost taste we seek ?


Is it?

:)

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Re: Time to end the war on Salt?

Postby to_our_health » Fri Sep 02, 2011 10:15 am

I met someone recently who said she developed a goiter after several years on a vegan low salt diet. But I didn't get to ask her about more specific details.

I know goiter can be the result of insufficient iodine which is why table salt is fortified with it. Would you point me to the links if this has been discussed before (probably has!) but if we're relying on our diet, only, for sodium, how/from where are we getting our iodine? Thanks!
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Re: Time to end the war on Salt?

Postby JeffN » Fri Sep 02, 2011 10:19 am

While it varies depending on soil, Iodine occurs naturally in foods.

http://www.fao.org/DOCREP/004/Y2809E/y2 ... htm#bm18.4

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Re: Time to end the war on Salt?

Postby to_our_health » Fri Sep 02, 2011 12:40 pm

JeffN wrote:While it varies depending on soil, Iodine occurs naturally in foods.

http://www.fao.org/DOCREP/004/Y2809E/y2 ... htm#bm18.4

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So iodine occurs naturally in foods to the extent it is present in the soil. I'm assuming that since you haven't brought up that getting enough iodine is a problem, you are confident our food is grown in soil that provides enough iodine. Would that be a correct assumption? If so, is that based on studies that for example, monitor the iodine content of soil where food is grown? (I'm wondering because I'm thinking of those areas of the US historically where the soil was deficient, people developed goiters and that's why iodine was added to table salt.)

Thanks again!
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Re: Time to end the war on Salt?

Postby JeffN » Fri Sep 02, 2011 3:03 pm

to_our_health wrote:
JeffN wrote:While it varies depending on soil, Iodine occurs naturally in foods.

http://www.fao.org/DOCREP/004/Y2809E/y2 ... htm#bm18.4

In Health
Jeff


So iodine occurs naturally in foods to the extent it is present in the soil. I'm assuming that since you haven't brought up that getting enough iodine is a problem, you are confident our food is grown in soil that provides enough iodine. Would that be a correct assumption? If so, is that based on studies that for example, monitor the iodine content of soil where food is grown? (I'm wondering because I'm thinking of those areas of the US historically where the soil was deficient, people developed goiters and that's why iodine was added to table salt.)

Thanks again!


There are only two isolated accounts in the world of issues related to soil related mineral deficiencies and both occurred in small isolated areas where virtually all their food came from within a very limited local area.

Today, no matter where you live in the USA, your food comes from a variety of sources around the world and contrary to popular myth, we have some of the richest soils ever.

In addition, if you are using the Eden Foods canned beans, they have a some iodine added that comes from the kombu.

Lastly, unless you are following a 100% no salt added diet and you are using some regular table salt, you are getting some iodine from the salt. There is about 77 mcg of iodine per gram of table salt and a tsp is 6 grams. So, 1/4 tsp (which is 550 mg sodium) is about 115 mcg iodine, and 1/3 tsp (which is about 775 mg sodium) is about 154 mcgs of iodine. The RDA is 150 mcg/day for adults.

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