It's Time to End the War on Salt | Hacker News Reader

It's Time to End the War on Salt

scientificamerican.com

155 pointspitdesi51 comments

Here's a big copy paste from Harvards school of public health: www.hsph.harvard.edu/nutritionsource/salt/jama-sodium-study-flawed/index.html

A new study would have you believe that low-salt diets raise your risk of dying from heart disease—a surprising finding, and one that’s sure to grab headlines worldwide. The only problem is that the study’s conclusions are most certainly wrong.

In the study, published in the May 4, 2011, issue of the Journal of the American Medical Association (JAMA), European researchers followed 3,681 men and women for an average of about eight years. (1) They report that people with the lowest levels of sodium in their urine (a marker of salt intake) at the start of the study had a 56 percent higher risk of dying from cardiovascular disease than people with the highest levels. Equally unexpectedly, among the 2,096 participants who had normal blood pressure at the start of the study, urinary sodium appeared to have no effect on the development of high blood pressure over six and a half years.

Based on these findings, the study authors call into question recent estimates (2, 3) of the tens of thousands of heart attacks, strokes, and cardiac deaths that could be averted each year—and the billions of healthcare dollars that could be saved—by curbing Americans’ excessive salt intakes. Yet the study has several weaknesses, chief among them its modest size: With less than 4,000 participants—and only 84 deaths due to cardiovascular disease—the study is too small to support the authors’ sweeping conclusions.

Read about why cutting back on salt and sodium is a key to good health

Read about key studies that show the harmful effects of sodium on the heart

Furthermore, the study’s findings are inconsistent with a multitude of other studies conducted over the past 25 years that show a clear and direct relationship between high salt intakes and high blood pressure, and in turn, cardiovascular disease risk. (4–10)

“Take this study with a huge grain of salt, and then dispose of it properly,” says Dr. Walter Willett, chair of the Dept. of Nutrition at Harvard School of Public Health. “This study should not influence recommendations about sodium intake in any way.

Key problems that undermine the study’s conclusions include the following:

Unreliable measurement of sodium intake: The study investigators base their main findings on a single measurement of sodium collected at the start of the study specifically the amount of sodium that study participants excreted in their urine over a 24 hour period. Yet sodium excretion from just one day does not reflect people’s salt intake patterns over long periods of time. It’s weak science to use one-day sodium excretion to predict heart disease or mortality decades later. Failure to account for key factors that influence sodium intake and heart disease risk: People who are taller (11) or more active (12) tend to have a lower risk of heart disease. They also tend to have higher sodium intakes, simply because they eat more food. Yet the JAMA study authors don’t account for differences in height, physical activity, and total calories. (13) This oversight could make it appear as though high sodium intakes protect against heart disease deaths, when in fact physical activity or height is responsible for the lowered risk. Other weaknesses: There are other problems with the way that the investigators conducted the study, among them, missing or incomplete data from large numbers of participants. The study investigators, for example, could have accounted for incomplete urine samples by analyzing urinary sodium in relation to creatinine (another compound found in urine), but they did not.

The bottom line is that the researchers were trying to ask questions that their data are incapable of answering, and the study’s many methodological problems make its results unreliable. So the study’s findings do little to refute the strong evidence that cutting back on sodium would save lives.

Americans, on average, consume about 3,400 milligrams of sodium per day. Current U.S. recommendations call for a maximum of 2,300 milligrams of sodium a day (the amount found in a teaspoon of salt), and 1,500 milligrams of sodium (two-thirds of a teaspoon) for people who have high blood pressure or are at high risk of developing it. The latter group includes people who are over the age of 40, are African American, or have somewhat elevated blood pressure (prehypertension)—a group that includes almost 70 percent of adults in the United States. (14) A dash of prevention is worth a pound of cure: Since 90 percent of Americans will develop high blood pressure at some point in their lives, (15) it really makes sense for all of us to curb our sodium intake.

Read more about how to preserve flavor and cut back on salt

Try these delicious low salt recipes from the Culinary Institute of America

Seventy-five percent of Americans’ sodium intake comes from processed foods. (16) That’s why the Institute of Medicine has called on the U.S. Food and Drug Administration to regulate the amount of salt and sodium allowed in processed foods. (10) References

1. Stolarz-Skrzypek K, Kuznetsova T, Thijs L, et al. Fatal and Nonfatal Outcomes, Incidence of Hypertension, and Blood Pressure Changes in Relation to Urinary Sodium Excretion. JAMA. 2011; 305:1777–85.

2. Palar K, Sturm R. Potential societal savings from reduced sodium consumption in the U.S. adult population. Am J Health PromotOpens in New Window. 2009; 24:49–57.

3. Bibbins-Domingo K, Chertow GM, Coxson PG, et al. Projected effect of dietary salt reductions on future cardiovascular disease. N Engl J MedOpens in New Window. 2010; 362:590–9.

4. Strazzullo P, D'Elia L, Kandala NB, Cappuccio FP. Salt intake, stroke, and cardiovascular disease: meta-analysis of prospective studies. BMJOpens in New Window. 2009; 339:b4567.

5. Intersalt: an international study of electrolyte excretion and blood pressure. Results for 24 hour urinary sodium and potassium excretion. Intersalt Cooperative Research Group. BMJOpens in New Window. 1988; 297:319–28.

6. Cook NR, Cutler JA, Obarzanek E, et al. Long term effects of dietary sodium reduction on cardiovascular disease outcomes: observational follow-up of the trials of hypertension prevention (TOHP). BMJOpens in New Window. 2007; 334:885-8.

7. Cook NR, Obarzanek E, Cutler JA, et al. Joint effects of sodium and potassium intake on subsequent cardiovascular disease: the Trials of Hypertension Prevention follow-up study. Arch Intern MedOpens in New Window. 2009; 169:32–40.

8. Appel LJ, Moore TJ, Obarzanek E, et al. A clinical trial of the effects of dietary patterns on blood pressure. DASH Collaborative Research Group. N Engl J MedOpens in New Window. 1997; 336:1117–24.

9. Sacks FM, Svetkey LP, Vollmer WM, et al. Effects on blood pressure of reduced dietary sodium and the Dietary Approaches to Stop Hypertension (DASH) diet. DASH-Sodium Collaborative Research Group. N Engl J MedOpens in New Window. 2001; 344:3–10.

10. Institute of Medicine. Strategies to Reduce Sodium Intake in the United StatesOpens in New Window. Washington D.C.: National Academies Press. 2010. Accessed May 3, 2011.

11. Ferrie JE, Langenberg C, Shipley MJ, Marmot MG. Birth weight, components of height and coronary heart disease: evidence from the Whitehall II study. Int J EpidemiolOpens in New Window. 2006; 35:1532–42.

12. U.S. Dept. of Health and Human Services. 2008 Physical Activity Guidelines for AmericansOpens in New Window. 2008. Accessed May 3, 2010.

13. Willett W, Stampfer M. Implications of Total Energy Intake for Epidemiologic Analysis. in Willett W, Nutritional Epidemiology. New York: Oxford University Press, 1998: 273–301.

14. Application of lower sodium intake recommendations to adults—United States, 1999-2006. MMWR Morb Mortal Wkly RepOpens in New Window. 2009; 58:281–3.

15. Vasan RS, Beiser A, Seshadri S, et al. Residual lifetime risk for developing hypertension in middle-aged women and men: The Framingham Heart Study. JAMAOpens in New Window. 2002; 287:1003–10.

16. Brown IJ, Tzoulaki I, Candeias V, Elliott P. Salt intakes around the world: implications for public health. Int J EpidemiolOpens in New Window. 2009; 38:791–813.

Um, why the giant copy & paste?

What would have been wrong with a clickable link (http://www.hsph.harvard.edu/nutritionsource/salt/jama-sodium...) and small salient excerpt?

Also, this Harvard article is strictly raising concerns about a May 2011 JAMA paper. The Scientific American 'End the War on Salt' article also relies on a "meta-analysis of seven studies" published in July, and talks of another 11-trial review of the effects of sodium-intake-reduction in 2004.

The SciAm article makes it sound like there is literally no scientific support in "the war against salt." This article pretty clearly claims exactly the opposite, so it makes a good counterpoint even if it was published before the most recent study.

>Um, why the giant copy & paste?

When I click on that link, a registration thingy pops up. You can dismiss it, but OP might have thought registration was required.

While the causes of too much salt are debated, I see fairly regularly the effects to too little salt.

In a hot climate (Southeastern U.S.), I'm often outdoors with sports teams or youth groups, and I see the effects of heat-related conditions regularly. These are prevented and treated with water and salt (electrolytes). [1] [2]

So yeah, too much salt may be a problem. Maybe not. But too little certainly is, and it's common in the active youth I observe.

1: http://en.wikipedia.org/wiki/Hyperthermia 2: http://en.wikipedia.org/wiki/Electrolyte

Couple things here, and I say this with the utmost respect. Your anecdote is not "data", and even if it were, you've failed to prove any sort of causality of "too little salt". Salt is but one of many possible electrolytes, and and "heat related conditions" are not necessarily solved with salt; chances are dehydration clear and simple could also be the cause of the effects you're seeing.

Hyponaetremia is well-documented, and I'm sure someone who has spent a summer supervising children in the heat can tell the difference between hyponaetremia and dehydration. With utmost respect, you sound like you haven't had first aid training and you don't spend much time outdoors in hot weather.

Thanks for the support. I think GP is right to be cautious (and data is not necessarily equivalent to multiple anecdotes over more than a decade). However, I would assert that my experiences are not unique.

You are correct that the symptoms are different [1][2], and that first aid training (in my case, Red Cross) acknowledges the necessity of both fluids and electrolytes.

More broadly, the term "[D]ehydration, despite the name, does not simply mean loss of water, as water and solutes (mainly sodium) are usually lost in roughly equal quantities" [3], meaning that even if water is replenished, salt intake must also be increased.

It's been my experience (and we're back to anecdote, unsupported by my first aid training) that dehydration may occur quickly (especially in hot weather), but insufficient electrolytes occurs over a period of days of insufficient replenishment (e.g., training, sports tournaments, resident camps).

1: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001431/ 2: http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001977/ 3: http://en.wikipedia.org/wiki/Dehydration

A somewhat peripheral question, but if we all cut back on salt intake where are we going to get our dietary iodine from? I lived in Italy for several years, where salt is (was? might have changed) not iodized and I regularly saw people with huge goiters in the throat.

Iodine could be taken in supplements or added to other common foods.

There are plenty of people on low-salt diets in the US under the supervision of doctors and participating in clinical studies. If it were to become a problem here, it's not one that's likely to go unnoticed.

Two things.

1. It's possible that we've reversed the causal association for all these years. You don't always get expansion of the extracellular fluid space with chronic kidney disease due to hypertension; with some tubulointerstitial diseases, you develop salt-wasting nephropathies. Perhaps these were the hypertensive patients who were referenced in the article, voraciously eating salt due to a deficiency caused by their kidney disease? I'd like to see more data before being willing to overturn dogma, but it's not the most outlandish idea I've heard all day. Still, the authors' conclusions are most likely wrong.

2. There's a group at MGH doing a randomized clinical trial in which they are administering intravenous salt and measuring near-term blood pressure response. It's a one-off exposure, but it will be interesting to better nail down the relationship between serum sodium content and blood pressure via experiment rather than epidemiology.

"It's possible that we've reversed the causal association for all these years."

This is intriguing, because a similarly reversed causality was prevalent in the diagnosis and management of kidney stones for many years.

Perhaps this is TMI, but as a chronic kidney stone sufferer, I was told initially that I get too much calcium in my diet -- which builds up to cause the stones. Eventually, the doctors came around to the idea that I was actually secreting too much calcium into my bloodstream, and that secretion and consumption are not the same thing. In fact, I am losing more calcium than I consume, and I am losing much more than I should. Basically, I am deficient in calcium, even though my serum calcium levels are through the roof. (This phenomenon has underlying causes above and beyond the kidney disease; in fact, the kidney disease is most likely a secondary effect).

There's probably some things you can do about that in terms of dietary changes and supplementing other minerals/nutrients to help your body better deal with calcium. As a guess, you are probably also too acid (the body dumps calcium from the bones to mediate the blood PH, so what you describe can be due to high acidity). I have a condition which is essentially a salt-wasting condition and I found that getting enough salt wasn't enough. I had to get enough salt along with certain other things to properly absorb it. That approach reversed a lot of my symptoms (which are supposed to be irreversible). I've also worked a lot on kidney health. But don't have time to elaborate at the moment as I have to get ready for work.

It's possible that we've reversed the causal association for all these years.

Another possibility: Cortisol. People under chronic stress produce more cortisol, and high cortisol levels act to inhibit urinary sodium loss. Maybe the people having heart attacks aren't eating more sodium; they're just retaining it better as a side effect of the stress which is killing them.

The problem of correlation vs causality.

Stress, cortisol, and let's not forget sleep deprivation -- also typically associated with the same lifestyle, also highly deleterious to health, and also correlated with heart disease.

Right, my point was that cortisol is the link between "lifestyle which results in early death" and elevated serum sodium.

Understood your point; was just adding to it. Sorry for the confusion.

>But if the U.S. does conquer salt, what will we gain? Bland french fries, for sure. But a healthy nation? Not necessarily.

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."

The article goes out of its way to dismiss the other impact of "French Fries" on health, obesity, and the role which salt plays in making manufactured food with low nutritional value habit forming.

http://www.sciencedaily.com/releases/2006/11/061101151027.ht...

Which seems to be mainly down to drinking more non-water liquids.

So... maybe the effort expended in reducing salt intake should instead be spent on increasing water as a beverage choice?

Seems to me, that if people would readily forgo consuming flavored food products in lieu of something with little taste, a correlation between salt and obesity might be less likely to begin with. In other words, one could promote carrots in lieu of French Fries and expect similar results.

The entire process of diagnosing people with hypertension needs a shake up. Managing blood pressure is such an important part of the human condition but the evidence as to what works and what doesnt can be confusing. Weight loss and stopping smoking works, but for exercise, cutting alchohol and cutting salt there are many conflicting reports.

Add in the fact that genetics plays such an important part, and the prevelence of White Coat Syndrome it's a shame that the medical world cannot make its mind up.

The confusion around hypertension is really annoying. I have a bit of white coat hypertension, and my BP is usually around 145/80 when measured by a medical professional, but is still around 132/80 when measured automatically. Getting it down to 120/80, or lower (where everyone else who I know in my age group is, and which seems to be the safest in the long term) is stubbornly impossible, despite exercise and a healthy diet. A 24 hour workup by a doctor seemed to point to stress-induced hypertension, but I was told that there's no need to treat it.

Is hypertension brought on by being stressed/awake less harmful than "intrinsic" hypertension? That seems to be the opinion by my physician. But it's maddening that these issues remain unresolved.

What exactly do you eat / drink on an average day?

I usually have a cup of tea for breakfast and grilled cheese + tomato sandwitch for lunch. Dinner is either poached fish, grilled or curried chicken, steak or lambchops, and often features french fries or rice. Popcorn for a late snack. No alcohol. I avoid coffee, but have 2-3 packets of potato chips and the equivalent of 2 glasses of Coke a day (I think I'm hypersensitive to caffeine, and any caffeine after 4PM screws with my sleeping patterns). 2-3 eggs on weekends.

At one stage I had salad for lunch for about a year, and tried to eat vegetables 5 days a week, but it didn't seem to influence my BP.

I exercise a lot less than I used to, but when I exercised 4 times a week, I'd regularly check my BP before starting, and, if anything, it was higher than it is now. But I am trying to psych myself up for exercise for other reasons - I need to offset the general malaise that comes from being behind a desk the whole day.

While I don't know what such a diet means for hypertension, it sounds pretty poor in terms of nutritional value. You might have less malaise if you ate more fruits and vegetables, and weren't sending your blood sugar on a roller coaster with those two glasses of coke. Two cans of coke supplies over a quarter of the recommended daily carbohydrate intake!

Try eating nuts or seeds as a snack. The protein will help balance your energy levels and the fat will keep you satiated. Look at granola instead of potato chips -- not the top brand ones bars that are just sugar delivery mechanisms, though.

And really, you should eat breakfast! The first meal of the day has a lot of important effects. http://www.webmd.com/diet/guide/most-important-meal

I sleep ~6 hours per night, drink 6+ cups of coffee and 1-2 cups of tea per day, and only rigorously exercise for 25 minutes 2-3 times per month. My daily diet consists of 600+ calories from extra-virgin cold-pressed coconut oil and butter, 2-4 eggs a day, a handful of cherry tomatoes, 1000+ calories from beef/poultry/pork/fish, 400+ cals from hard cheeses (like swiss), a 1/2 pound - 1 pound of vegetables, maybe a handful of mixed nuts, and a whole lot of kitchen spices (including salt!).

I also try to take 5 - 10 minutes a day to do focused breathing/relaxation (i.e. meditation w/o the hocus-pocus).

With the above lifestyle, I have a resting pulse rate of 54, a bp of 122/70, and I have been losing 2-8 lbs a month for the past 18 months while maintaining strength, endurance, and muscle mass levels. Moreover, I feel wonderful!

I turn 30 at the end of the year, so my good results aren't because I am some youthful, exuberant teenager. I actually attribute them to my diet and lifestyle.

Traditional 'healthy' diet (low fat, low salt, high on carbs and grains) is very bad for health.

Your diet seems to be mostly keto (I assume your coffee and tea are sugarless). The diet of ern is very far from keto.

There are two very active community of redditors (keto and Paleo) with very good info on diets and foods that work to have good health, and bibliographies with explanations of why it works.

I like to think of my diet as "early-Neolithic". I am from one of the populations groups with adult lactose tolerance. So, I modeled it on the foods that might be available to what used to be called a "gentleman farmer".

I also recognize that scientific research has made real progress on determining what to eat in the past few years; so, I've also tried to incorporate some of those findings as well.

Read Gary Taubes - he makes a convincing case for reducing carbs (sugar, bread, potatoes, rice) drastically to combat high blood pressure.

I'm 25 and in the exact same situation as you, except that my baseline is probably a more like 135/80 or even 140/80. I know that weight loss works, because a couple of years ago when I weighed about 40 lbs. less, it tended to be more like 130/80. But then I quit smoking (which I had taken up for ~3 years by that point) and started eating the world. Yes, ironically by BP was lower when I abused the crap out of stimulants, smoking and drinking coffee around the clock like a champ. However, I think those things are unrelated; significantly lower weight might have offset all that.

I am very wary of physicians' periodic mumblings about putting me on hypertension meds soon because this could be doing "silent damage". I'm aware of that. But I know several hypertensive people, in otherwise good health and relatively young age, who had anomalous, out-of-the-blue heart attacks or strokes suspected to be linked to side effects of calcium channel blockers or other hypertension medication. It makes me very wary.

It seems to me the only safe adjustments to BP outside of a gerontological context can be made through lifestyle and weight changes.

I got a blood pressure monitor about a week ago. The men in my family have a history of high blood pressure, but my diet and exercise and body composition has been so dialed in the last six months that I was expecting my blood pressure to be at normal levels. But to my surprise, that wasn't the case. After going cold turkey on my Coke Zero habit and doubling my fish oil intake, I gradually went from 145/85 to around the 120/70 range over the course of a week.

I can't know if the drop was caused by those dietary changes. It could have been due to a few days of elevated stress, though that doesn't correspond to my subjective experience. It could have been due to the sodium content in the Coke Zero. It could have been due to the caffeine, except all the research I found states that caffeine intake only leads to a very short-term elevation in blood pressure. But I'm sleeping much more soundly now due to no caffeine, so that might be it. The extra fish oil could also have helped, but it's unlikely to account for most of the drop.

Sleep seems like the most likely candidate. I didn't have problems sleeping even when I was drinking a lot of caffeine, but there's no doubt the quality of the sleep was subpar.

For reference, and for those who may not have already read it:

"The (Political) Science of Salt", Gary Taubes. Science. 1998. 281: 5379; 898-907

http://web.archive.org/web/20060923051143/http://www.nasw.or...

Here's a link to this paper that's a single page and doesn't require going through archive.org:

http://storyarchive.tumblr.com/post/9437438977/the-political...

While tangentially related, I am compelled to deliver a pointer to Alton Brown's special on the mysterious mineral which is salt, Eat-This-Rock.

http://www.foodnetwork.com/good-eats/good-eats-eat-this-rock...

Or for the brave: http://www.youtube.com/watch?v=0f62XQPBlTE

Interesting bit:

>>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 <<

If I'm reading this correctly it is saying that people that urinate less sodium have higher chances of dying from heart disease. Then the author uses this as evidence that less sodium actually increase your chances of dying from heart disease.

If so then I would hypothesize that less sodium could simply mean that the body is no longer able to expunge it from the body and hence that is what is causing the heart disease.

"less sodium [output] could simply mean that the body is no longer able to expunge it from the body"

"the less sodium that study subjects excreted in their urine - an excellent measure of prior consumption"

These two statements seem mutually exclusive. If the amount of sodium a subject excretes is an excellent measure of prior consumption (ie, more out is demonstrably linked with more in, and less out = less in), then your hypothesis (less out may mean more retained, and therefore output can't be linked to input) cannot be true.

Of course, it could also be the "excellent measure" which is incorrect - my point is simply that these two are contradictory.

Or it could also be that people that were eating less salt where the ones that had a history of heart problems (their own or their parents) so it had nothing to do with the sodium intake.

>>my point is simply that these two are contradictory

My hypothesis assumes that the following statement is false on sick individuals.

>>"the less sodium that study subjects excreted in their urine - an excellent measure of prior consumption

Hence there would be no contradiction.

You're assuming that statement is false in specific cases; the OP assumes it is true in all cases - that sounds like a contradiction to me.

IMO, one of the most overlooked variables in the great salt debate is potassium deficiency:

'The 2004 guidelines of the Institute of Medicine specify an RDA of 4700 mg of potassium for adults,[2] based on intake levels that have been found to lower blood pressure, reduce salt sensitivity, and minimize the risk of kidney stones. However, most Americans consume only half that amount per day.'

Personally, I think we have a potassium, weight, and pre-diabetic problem, not a salt problem.

Not much more to say after Tim Harford…

MoreOrLess: Is salt bad for you? 19 Aug 2011

http://itunes.apple.com/gb/podcast/more-or-less-behind-the-s...

Starts at about 00:45 up to 16:07.

Anecdotal, I know, but in my experience my blood pressure is directly correlated with alcohol consumption. I used to be a consumer of 2-3 beers daily. At this time, I was also running approximately 15 miles per week, and working out at the gym. I was about 20 lbs heavier and had borderline high blood pressure. One day I cut out the beer intake, pretty much completely. The 20 lbs have fallen off, blood pressure is normal to below, and I cut back my running to 3-5 miles per week. I crave salt and eat plenty of it with an otherwise healthyish diet(that didnt change)

I understand their position up until the point of The NEJM Feb 2010 study, where they are dismissive of it as "conjecture". Granted it's a computer simulated model but they are using valid data from the National Health and Nutrition Examination Survey and the Framingham Heart Study.

Do they still treat hypotension by increasing a patients dietary salt intake?

Once again, yet another diet-related study which reinforces the old maxim of everything in moderation (including moderation, of course :-)).

I wish this article was programming related somehow.

A lot of us partake in the coffee and/or diet soda while programming. This jacks with our BP and invariably the subject of sodium comes up.

And it's about time. :)

a) War on ______ tends to be a sensationalist phrase that causes me to flip the bozo bit.

b) This article doesn't have anything whatsoever to do with tech or startups.

For (b), a lot of articles submitted here have nothing to do with tech or startups. That doesn't mean we wouldn't be interested in reading them. I think the HN community tends to know what the HN community wants to read more often than not.

Technology, startups, business, and workaholics' diseases. I also think they fit fairly well together.

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