Dear Mark: Salt and Blood Pressure
The salt debate rages on outside these halls, but I’ve never really opened MDA’s doors to the tempest (beyond a short dalliance several years ago). Today, though, I am. We’ve likely all consumed a fair bit of sodium chloride over the past holiday weekend, and I imagine a few of us are wondering whether that’s a problem or not. Ever timely, reader John has written in with his salt story and a simple question: how much salt is suitable for humans?
Here’s his question:
I went Primal last year, and I’m down about 25 to 30 pounds and blood pressure is lowered. I have definitely followed your advice on low salt. For example, if I buy tomato sauce or paste, I get the “No Salt”, and I buy the low salt cashews, preferably with sea salt. What do you think about this new research that has come out, saying that salt is not that bad for you, and that it’s not actually related to heart disease? Just wanted your take.
John
There’s a lot of back and forth on salt, even among mainstream researchers. It used to be that dietary salt was absolutely evil, that it would spike your (everyone’s!) blood pressure and cause certain heart attacks and stroke. I mean, your average health-conscious grandparents probably still eat all their foods unsalted because, along with egg whites and 1% milk, that’s just how you ate when you were trying to lower blood pressure and reduce the risk of an early death. But then stuff like the research to which John is most likely referring rolls around: this study (from the Cochrane Review in the American Journal of Hypertension) that Scientific American featured in its recent story, “It’s Time to End the War on Salt.” In fact, salt is kinda like the new egg. Will it or won’t it (kill you/clog your arteries/give you cancer/enter nefarious-sounding characteristic of necessary dietary component here)?
First of all, outright demonization of an element as important as sodium is silly and foolish. We literally have a physiological requirement for sodium (about 500 mg per day), and we come equipped with sensory apparati on our tongues (taste buds) specific to salt and extant for the express purpose of identifying salty things so we can consume them. It’s obvious that salt is necessary, and that it’s not poison. In fact, it:
- Supports the nervous system – both sodium and chloride (also known as sodium chloride, or salt) are necessary for the firing of neurons.
- Regulates blood pressure – keeps it from going too low or (usually) too high.
- Helps maintain acid-base balance and blood volume.
- Supports the function of the adrenal glands which produce dozens of vital hormones, including the stress and sex hormones.
But how much is too much? Is there such a thing as a limit to sodium intake?
Loren Cordain thinks the amount of salt average Americans get daily – almost 10 grams, or 3,875 mg of sodium – is excessive and evolutionarily discordant as indicated by the earliest evidence of salt mining by homo sapiens coming from China in 6000 BC and Spain in 6200 BC, well after the advent of agriculture. In his paper, he acknowledges the likelihood that coastal dwellers “may have dipped their food in seawater or used dried seawater salt,” but doesn’t find that the totality of evidence supports high sodium intake by humans during the Paleolithic. While I agree with 10 daily grams of refined salt being evolutionarily discordant and possibly excessive for some people, I think he’s overlooking something.
There’s plenty of evidence that the earliest humans were largely coastal dwellers with a fondness for seafood – particularly shellfish, which are rich in sodium. As I wrote in that shellfish post, basically any culture with coastal access left behind ample evidence of constant shellfish consumption. Some researchers are even suggesting that a bottleneck in human evolution occurred sometime between 190k and 130k years ago, when the total human population was reduced to about a thousand individuals living on the coasts of South Africa, eating a diet rich in seafood and especially shellfish. If it is from those thousand-odd humans that every current living human descends, and they were big shellfish eaters, I’d say it’s pretty likely that we can tolerate a decent amount of salt.
According to the USDA database, three ounces of raw clams, oysters, and mussels provide 510 mg, 90 mg, and 243 mg of sodium, respectively. I even think they’re undercounting the sodium content of oysters, personally. I regularly eat raw oysters on the half-shell, and there’s no way that mouthful of briny goodness contains just 90 mg of sodium. I’m guessing they measured the oysters rinsed and cleaned and from a jar, rather than slurped straight out of the shell. If our direct ancestors (all of them, assuming this bottleneck occurred) ate steady amounts of salty seafood straight out of the shell/sea, then salt can’t be bad, right?
Kinda. Some people are genuinely “salt-sensitive.” When they consume higher levels of salt, their blood pressure increases. When they drop the salt intake, their blood pressure drops with it. Studies indicate that of patients with hypertension, 51% are salt-sensitive (73% of African-American hypertensives are salt-sensitive), while 26% of normotensive patients are salt-sensitive. And since we know sodium chloride plays a physiological role in the regulation of blood pressure, this isn’t controversial in the least. But the majority of randomized controlled trials have been inconclusive regarding the effects of salt on hypertension, as the Cochrane Review mentioned, and some studies have found a slight increase in disease from “low-salt” diets. Another found “normal sodium” diets resulted in better outcomes for congestive heart failure patients than “low sodium” diets (less followup hospitalizations and certain blood markers). The evidence is mixed and murky, for sure.
That said, there’s way more to blood pressure than just salt intake. Like:
- Fructose. Yes, fructose is strongly linked to hypertension. One study found that omitting one 12-oz sugary drink per day lowered BP. Dietary fructose increases salt absorption by the kidney, thus suggesting a synergistic effect between fructose and salt intake; you ditch the sugar and maybe the salt isn’t such an issue. Of course, salty and sweet often accompany each other in the industrial food world, probably to the kidney’s ultimate detriment.
- Or potassium. Some research indicates that the dietary potassium:sodium ratio is more important than the absolute level of sodium in the diet. Although Ned Kock suggests that it may just be another marker for a healthy diet rich in real food.
- Or general processed food intake. I’ve discussed this before, but consider that processed food accounts for most of the sodium in the average person’s diet. As one survey of the worldwide dietary sodium scene found, over 75% of sodium intake in North America and Europe comes from manufactured food. Asian countries consumed twice as much sodium on average than other regions, but consumed less processed food. I think it’s plausible that sodium intake is often just a proxy for processed food intake in epidemiology, and that’s partially explaining the rise in hypertension – not just the salt alone (although that obviously plays a role in certain individuals’ hypertension).
- Or stress. Psychosocial stress is a likely cause of hypertension, even among people with low-salt diets. Well-adjusted, socially-fulfilled lab rats don’t get hypertensive on high-salt diets, while Malawi adults on low-salt diets get hypertensive when exposed to modern stressors.
The simple answer is that there is no one simple answer regarding the health effects of salt. It’s clear that while salt intake alone does not determine blood pressure for everyone, or even most, a certain portion of the population appears to be salt-sensitive; in this population, sodium intake increases blood pressure and decreasing intake decreases it. The genetics of salt-sensitive hypertension are complicated, undoubtedly with different epigenetic triggers and environmental contexts for the various manifestations, and experts are still mulling over specific recommendations in 2011.
I have a few somewhat specific recommendations, however:
Rather than obsess over the amount of salt in your diet, focus on eating enough potassium-rich foods, avoiding excessive fructose, and managing your stress. These will do more for your heart health, blood pressure, and overall enjoyment of life than measuring out 1/8 teaspoons of salt. You think calorie counting is bad? Try sodium ion counting!
Avocados, sweet potatoes, chard, and most fruits are excellent sources of potassium. Work those things into your diet, if they fit your template.
So’s meat, actually, particularly red meat. Just be sure to eat your meat closer to rare than not, as raw meat contains more potassium than cooked meat. And let your steak rest before slicing into it after cooking; the potassium’s (and flavor’s) all in the juice!
Don’t be scared of reasonable amounts of fruit, especially if you’re active; just avoid refined sweets and excessive amounts of excessively sweet fruit.
Pay attention to how you’re feeling. If I have lots of cured meats or salty cheeses or I eat out on the road several days in a row, I start feeling kinda… not great and somewhat bloated and heavy. On the other hand, sometimes I feel genuine cravings for salty food. In both cases, I listen to my body.
If you’re interested, run your meals through a Fitday or a Cronometer or something similar, and track your sodium, potassium, and fructose intakes.
Try to eat considerably more potassium than sodium, but through food (at least a 5:1 ratio). We like to point out how sodium might just be a proxy for processed food intake, but the same could be said for potassium intake, which might just be a proxy for real food intake. Consuming a refined diet with no vegetation or fresh meat but supplemented with potassium salts probably isn’t the same as consuming a real diet with actual food containing ample potassium (though potassium salts subbed for regular salt has been shown to reduce blood pressure in hypertensive patients with naked tails). And whether it’s the potassium or the lack of sodium or the real food providing the benefits, eating the real food and using real salt when applicable while avoiding processed and sweetened junk will get you there.
As for determining whether you need to reduce sodium intake, it’s pretty simple. If you have elevated blood pressure (and it’s not just white-coat syndrome) and you are salt-sensitive, reducing salt intake should lower blood pressure over the course of a few weeks. Cut your salt intake by around half to test for salt sensitivity. A quarter teaspoon in the meal instead of a half teaspoon, unsalted butter instead of salted butter – that sort of thing. Nothing super rigorous, just a general reduction in sodium. Increasing your potassium intake will “confound the results,” but this isn’t some stiff objective study on strangers you’re running; this is your life and your health, so don’t worry too much about eating that avocado cause it’ll throw off the effect of a reduction in salt intake.
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Posted By: Mark Sisson
Great Post, Mark. Very interesting. I’ve never actively tried to reduce sodium but rather eat as much real food as I can and don’t really think about it. I’ve never had issues with high blood pressure. Thanks!
first post!
Definitely food for thought!! Thanks!
Dr Mort Satin of the Salt Institute spoke at the Weston A Price Foundation Conference last month. His opener was: “I am not here to convince you to eat more salt- one good snow in the NW sells more salt than the whole country can eat in a year.” He went on to discuss the salt phobia in the US. From the Battle of 1812, until after WWII, when refrigeration became more available for the military, most foods were preserved with salt, giving the average soldier about 19 grams of salt intake a day, apparently w/o ill effects. But recall that this was naturally derived salt, not the refined NaCl, and so was full of other beneficial minerals.
http://www.lancet.com/journals/lancet/article/PIIS0140-6736(11)61866-7/fulltext
Is Dr Satin’s article on dangers of lowering salt and coronary disease, published in Lancet,
Just a quick clarification. 3,875 mg is 3.875 grams, not “almost 10 grams”. Is the error Dr. Cordain’s? 10,000 mg would indeed be significant, but I’ve not seen any stats that indicate this. 3-4K mg seems to be the more usual number.
In any case, I agree that once you’ve cut out most processed foods with huge amounts of “hidden” sodium, it seems silly to worry about a bit of salt on our food.
The mass of “salt” they are measuring can be confusing. Salt usually means NaCl (Sodium Chloride), but what they’re really worried about is the Na, not the Cl. So in a paper where they talk about 10,000 mg of salt (NaCl), that’s about the same as 3,875 mg of Na. Does that make sense? So if you have 5 grams of salt, that equates to roughly half that weight in Na. Sodium is what has the main physiologic effects that they are studying.
Well, last I checked using the molar mass of sodium, it’s more like 39% of total mass of NaCl. Given 10g of NaCl, in a perfect solution you would have 3,934 mg of Na. But close enough, I guess? In any case, the wording is extremely confusing.
To add to the confusion, processed foods often contain sodium, not salt. I’m still not sure where the “10 g of salt a day” comes from. This seems higher than any other figure I’ve seen.
I am a 42 year old female, bp 105/60, rhr 55-57. I eat a lot of salt and drink a lot of Diet Coke (I know, I know…it’s my only vice and I am ditching it for my New year’s Resolution). If I didn’t have caffeine & salt, I don’t think my blood would even move! LOL
Seriously, though, everyone has different thresholds for everything and trying to tell people that one way is the right way is misleading and dangerous.
Eat as naturally as you can, move around a bit and RELAX people!
Happy holidaze.
10g of sodium chloride (salt) vs. 3.875g sodium
What a floodlighting post! Now I can salt my steaks without worrying so much about the amount.
Keep up the good work Mark!
Ah, the great salt debate. I’ve argued this one over and over again. Your answer, Mark is great! The bottom line to me will always be, “eat real foods”. Real quality foods taste so much better – you won’t find the need to add tons of salt to make your meal palatable. Buy and use an assortment of colorful sea salts – toss out the factory-produced, iodized, and anti-caking “salt products”. Listen to your body and listen to Mark at Mark’s Daily Apple.
I get a little annoyed whenever I hear lowering salt intake suggested as a universal recommendation. I have a condition for which the first-line treatment is to increase salt and fluid intake. A low salt diet could actually be dangerous for me. Granted, such medical conditions are not common, but they do exist. I think universal recommendations are therefore inadvisable.
I know two people who almost died from low sodium, thinking that if low is good, none is better. Bad idea resulting in an ambulance trip to the hospital in both cases.
ok – how about this Mark–
just as grok didn’t eat the tenderloin and chuck the entrails, he very likely didn’t drain the blood in the dirt- blood is salty – i’m sure the Masai get better salt rations from their blood/milk habits perhaps just as grok did? i mean, i’m personally not totally up to it, but warm, raw blood probably tasted pretty good to grok, no?–
so is our modern salt habit really that out of line??
personally i have always adored salt and consume a pretty healthy portion daily – i’m 56 and have always had low-normal blood pressure (combined with a very active energy level) and not a big athlete – i agree that sometimes a certain mix of foods with lots of salt is noticeable (like feeling my fingers being a bit thicker while playing piano or guitar), but it passes quickly with reduced consumption and a few more trips to the urinal–
finally, we have a pretty specific and efficient mechanism for dealing with too much salt – as opposed to our much more physiologically radical (and damaging) mechanism for overconsuming sugar – that alone would seem to indicate that a varied salt consumption is much more evolved – ie we’ve had a long time with lots of levels of salt consumption to adapt to.
your thoughts?
@ ravi,
you can feel thicker fingers playing piano? wow.
it is strange that i let go of the fear for SFA rather fast right after i switch my diet (spring 2010).
but salt took a longer time;
i was still brain washed about “salt = evil” when i signed up for a “dance boot camp” (5 hr/day) in the summer of 2010.
on the 3rd night, i had the worst cramps in my calves. i also developed the strongest craving for salt in my life.
i put salt in _EVERYTHING_ even plain whole fat yogurt, fruits (banana, pear, apple), etc. they tasted good salted.
then the cramps stopped. in a few days my taste bud returned to normal. (w/ the exception of plain yogurt which i now also salted. it tastes good to me that way than sweet).
regards,
If you stop eating processed foods, that frees up a lot of space for using the salt shaker. I like to put a little salt on the top of the food instead of inside the recipe. You get a good blast of salt right on your tongue without using that much actual salt.
Finally! I’ve been waiting for more salt information on this website. But I can appreciate holding back on a topic to think more carefully about it. I just have to say personally, though, that if you have adrenal exhaustion issues, it’s extremely important you add sea salt into almost all your meals. When I first started eating primal, I was still thinking the lower the salt intake the better. But then I went sprinting and ended up having these heart palpitations. I’d had them before spontaneously but could never connect it to anything – it would happen when I was well-slept and relaxed. But after this sprint, they just stayed for like three days straight. At first I thought I needed more potassium, but bananas didn’t solve the problem. Further reading revealed that people with adrenal issues often have electrolyte imbalance problems, especially with salt and magnesium. In fact, eating a higher amount of potassium from my diet may have thrown my electrolyte imbalance further off track. So then I ate lemon (which has some magnesium) and sea salt after reading that and the palpitations were gone. I kept on adding sea salt to my meals and in addition to them tasting better, the palpitations stayed away. I’ve since made sure that I’ve had enough salt before I exercise.
@MaloryVon,
thanks for the explanation of salt & adrenal fatigue.
that may explain why i had palpitation in May big time (work + rehearsals).
regards,
You know, when pregnant women start exhibiting hypertension and gestational diabetes, the main guideline for dietary change is the Brewer Diet, which is very paleo-like and includes absolutely no salt restricting. In fact, eating salt to taste/craving is linked quite strongly with better physiological outcomes during pregnancy. That was what first convinced me that salt restriction was ridiculous – if it makes babies and mothers healthier during a physiologically stressful time, why would it suddenly harm those who are not experiencing a metabolic event like pregnancy?
Hypertension seems so much more strongly correlated to an individual’s genetics and stress load than any one nutrient. I agree completely that the wisest course of action in most healthy individuals is to eat salt and listen to how their body reacts, using that as a litmus rather than some catch-all government recommendation.
Fructose also depletes phosphate in the liver in hepatic glycogen synthesis (converting to glycolytic substrates). This leads to the reduction of ATP to ADP to AMP and, finally, to uric acid. This uric acid accumulation via this process also can contribute to HTN.
I’d be interested in hearing thoughts about iodine and eating Paleo. As someone who already has hypothyroidism, I’m concerned I may not be getting enough iodine in my diet to support an already sluggish thryoid since I’m now eating Paleo. Some informal research online reveals that some people start having thryoid problems once they start eating Paleo because of the low iodine levels consumed. Doctors seem to know next to nothing about nutrition these days, so I thought this may be a question better posed to the Paleo community. Anyone have any experience/knowledge with this?
It depends on why you have hypothyroism. It could be autoimmmune, low iodine, calorie restriction or a VLC paleo diet.
As for VLC and hypothyroid, the fullness of liver glycogen influences how much thyroid hormone is made. Eating a slight excess of carbohydrate at about 30% of total calories will keep liver glycogen full.
We had someone tell us at uni about the dangers of salt. Clinical trials that reduced salt by ~30% managed to reduce blood pressure by about 2 mmHg. People with hypertension are 20+ mmHg too high. It’s certainly not the dominant factor.
Most whole foods (except eggs, dairy and shellfish) don’t have much salt so some added salt is a good idea.
The vitamin C helps clear uric acid so I doubt fruit would be a problem (which also possesses the raw materials to help metabolise fructose).
Interesting! Over Christmas, family members were talking about preferences for salty vs. not so salty food. Low blood pressure runs in our family, and all of the women with particularly low blood pressure are salt fiends, while other family members tend to prefer their food less salty. I wonder if our bodies are driving the salt cravings so we don’t get dizzy when we stand up too fast
If I don’t add salt to my food, my heart beats too fast and I get cramps and orthostatic hypotension. Is there an adjustment period where the body can learn to get by with less salt? As of now, I add 1/8 tsp to dinner everyday and that seems to break even with my output. More than that, my BP goes up, less than that, I get the above issues. But will I always need to add salt to my food? Do hunter-gatherers have access to a lot of salty things? I’m totally confused because I always thought my body would be fine without added salt.
Good sea salt gives you many trace minerals. I know the most highly recommended is Celtic Sea Salt (grey in color) and I use it extensively. But my favorite salts are pink Himalayan, my standard add-on salt in my grinder for meals, and for special occasions, Murray River sea salt. Fleur de Sel can also be a great addition.
I love to taste and test the various salts available, and pick the best one for the meal I’m eating at the moment.
I never salt a dish until it’s ready to eat and time to check the seasonings. I almost never eat prepared food, and make nearly everything from scratch — so added salt or naturally occurring salt is about all the salt I get.
Hey — even chocolate is better with a little salt!
Once I went primal, my blood pressure was/is no longer an issue. I can eat a handful of salt and my blood pressure doesn’t bobble one bit. Like I said, I am “primal;” I eat only foods I prepare myself. (I am 60 years old with a history of high blood pressure.)
Processed food can hide sodium in forms other than NaCl – Most prevalent is MSG which can cause havoc with almost everything hormonal.
About a month after going primal I had issues with orthostatic hypotension too. It was bad, to the point that every time I stood up I almost passed out. Then a post I saw here on the forums cleared it up, it referred to Dr. Eades, here he is discussing the biggest issues his patients have when going low carb:
“The good news is that it’s great to get rid of the excess fluid but it comes at a cost, which is the bad news. As the excess fluid goes, it takes with it sodium an extremely important electrolyte. When sodium levels fall below a critical threshold (which can happen within a short time), symptoms often occur, the most common being fatigue, headache, cramps and postural hypotension.
Postural hypotension happens when you stand up too quickly and feel faint. Or even pass out briefly. It’s a sign of dehydration. So if you’ve started your low-carb diet, made your multiple runs to the bathroom, and jump up off the couch to answer the phone and feel like your going to faint (or actually do pass out momentarily) and have to sit back down quickly, you’ve got postural hypotension. It’s really easy to fix – you simply need to take more sodium and drink more water. Salt your food more. Increasing sodium is just another one of the many counter-intuitive things about low-carb dieting. Just like eating more fat to lower your cholesterol. You’ve got to start thinking differently. The low-carb diet is one that absolutely requires more sodium. A lot more sodium.”
There’s a lot more in the post including Magnesium and Potassium. Here’s the link: http://www.proteinpower.com/drmike/saturated-fat/tips-tricks-for-starting-or-restarting-low-carb-pt-ii/ .
My daily regimen now includes a glass of Spicy Hot V8 and 16oz of water every morning which has 480mg Sodium and 650mg Potassium. If I start to feel light headed later I drink another glass of V8 and down 16 oz of water. It has cured my low blood pressure.
I had normal BP til towards the end of 2007. I was almost 63yrs. Dr wanted to medicate but I asked if I could try lifestyle changes first. She gave me 3 months. I reduced sodium to a maximum 1400mg per day, started exercising and losing weight (CW). BP normalised and I did not need meds. It could have been any of those 3 things or a combination of them. Fast forward to now. For the last several months I have been getting legs cramps almost nightly. Have tried everything. Increase fluids, decrease fluids, magnesium supplement, until 2 weeks ago. I stopped weighing, measuring and recording food intake as suggested by PB, instead I am following hunger cues. Because I could not measure sodium I stopped it altogether. The only sodium I get is from the whole foods I eat. Not one episode of leap out of bed in agony, leg cramps. Makes me hesitate to add it back that’s for sure. Just need to find a iodine supplement now.
Cramps are a symptom of potassium deficiency, which requires magnesium as the signaling molecule. A cramp is a muscle that has sufficient calcium and sodium to contract but insufficient magnesium and/or potassium to release/relax. Calcium signals sodium that makes muscle contract, magnesium signals potassium which releases the contraction, so to prevent cramps you need a sufficient supply of 4 minerals.
Massage works to relieve a cramp by pushing fluids containing potassium from above or below into the cramped muscle. Go here read this: http://goo.gl/qS18i
The only salt I add to food is Maldon Sea Salt from Essex in England. It tasts unlike any other Salt and comes in large flakes which add a crunchy texture to food. I eat virtually no processed foods and my blood pressure is on the low side.
After going primal, I don’t worry too much about these things. I hardly measure what I’m eating as long as I’m eating 80% primal and staying clear of junk food. And it’s worked for me, though I’ve never had a history of blood pressure. If you’re in reasonably good shape and eating real food, there’s not too much to worry about.
Interesting article, I think alot of people who dont look into things dont see salt for what it is, NaCl aka sodium chloride which we need to regulate our body.
“… has been shown to reduce blood pressure in hypertensive patients with naked tails”
So, this would be Mark recommending we all practice nudism — um…. so we can make more vitamin D?
Right? {wink}
Hi Mark,
Great article. I also don’t measure or count anything. I have switched to eating primarily whole foods, use a pea/rice/cranberry protein shake for convenience if needed, and my doctor said I have taken 30 yrs off my age (85 lbs less, cholesterol in half, etc). I have always had lower blood pressure, and have not been concerned about salt. However, I had made a switch to a good brand of sea salt. I thought it was the right thing to do. A short while ago I started reading “Killing Cancer…Not People” by Bob Wright. In this book I learned that sea salts are not the same – still processed and white, essential minerals are removed. The author recommends Himalayan Sea Salt – it is brownish pink in color. I found a source on line, but am concerned with the iron content, as too much iron contributes to cancer cell growth. Point is…even sea salt may not be the best. I know I will be looking into salts now and trying to discern the health benefits of the various types. Our bodies do need salt, more importantly we need iodine. In my on going quest for healthier living, I enjoy your posts – keep up the good work!
As Diane wrote, and I am VERY surprised Mark did not address is refined, processed (RE Unnatural) NaCl that we (I used to) eat as salt. A couple of years ago on my healthy journey, I had us switch to Sea Salt, and then to Himalayan Crystal salt. Much different than the NaCl processed and refined in most processed foods and from Morton, et. al.