#65: Can I Eat All the Salt That I Want?

0:00You read everywhere that you should reduce salt in your diet, and your doctor says that with your blood pressure, salt lowering is very important, but salt makes food yummy. What is the evidence actually tell us? Is salt actually a poison, or is that just a catchy slogan? Your body needs sodium to fire nerves and beat your heart, but we're also told it's quietly wrecking your blood pressure and blood vessels. So which is it? Essential nutrient? Modern killer? Or something in between? Hi, I'm Dr. Bobby DeBoys. Welcome to Live Long and Well, a podcast where we will talk about what you can do to live

1:02as long as possible and with as much energy and figure the truth. Together we will explore what practical and evidence-supported steps you can take. Come join me on this very important journey, and I hope that you feel empowered along the way. I'm a physician, Iron Man triathlete, and have published several hundred scientific studies. I'm honored to be your guide. At the so number 65, salt, poison, pleasure, or somewhere in between. Welcome back, end of one nation, or my dear listeners, to Live Long and Well. The podcast where I read this study, so you don't have to. I'm Dr. Bobby DeBoys, and I have no sponsors, no supplement deals, and no subscriptions, and no agenda other than telling you what the evidence actually says.

2:05So today, we're talking about salt, simple table salt. The white crystals your doctor tells you to avoid the thing your spouse hides from you after your last physical, the reason your french fries taste amazing, and your cardiologist looks worried. Salt has been called the slow poison public health campaigns have spent decades urging Americans to slash their intake, and the official guidelines from the American Heart Association, the CDC, and the World Health Organization all agree, eat less sodium. But here's what I find interesting, underneath that confident public health message, it's a genuinely complicated scientific story. Not all people respond to salt the same way, not all health risks are created equal,

3:11and in some scenarios, the evidence is a lot weaker than the confident recommendations would suggest. As my listeners know, I look at life as a risk-benefit trade-off. Never driving a car would reduce my risk of a motor vehicle accident. Enjoying small amounts of alcohol may raise certain risks a little bit, but driving a car brings freedom and drinking wine brings enjoyment and likely social interaction. So today we're going to look at salt in a similar way. Is it truly a poison and everyone should avoid? What are the risks and how about the pleasure that we get from enjoying our food? The next 20 minutes or so, we're going to do what we always do. Go to actual human studies, not animal models, clinical evidence in real people, and we're going to ask three questions.

4:17Question one, does salt always matter if you have high blood pressure? Question two, does salt matter if you have heart or kidney risk factors, but normal blood pressure? And question three, what about everyone else who may be basically healthy? Now most all points I will make are based upon pretty rigorous evidence, but in the end, it is really about my opinion on the evidence and others may understandably see the world differently. As I've shared before, sure sign of hype is when the expert claims the issue is absolutely clear. These issues are not absolutely clear and there is value and how both sides might view the evidence. And when I get to talking about using an end-of-one approach to see if your body is salt-sensitive,

5:19sadly, there aren't rigorous outcome studies for this topic. So reflect on what I will share, but do talk with your physician. I am not your doctor, but an educational resource that can help you raise issues to discuss with your provider. So take what I say with a grain of you-guested salt. First, some background on salt. 5,000 years ago, our ancestors learned that salt can preserve food and it changed their way of life. No longer did our ancestors need to eat only what was seasonal or just killed. They could save food for later eating, and it made food tastier. Salt became the most traded commodity in the world and the most taxed. In Rome, soldiers were paid in salt and that is the origin of the word salary and the phrase worth your salt.

6:27Other great salt phrases include salt of the earth, rub salt into a wound, and back to the salt mines. Table salt is sodium chloride. Two atoms stuck together. Sodium and chloride, NACL. Your body needs sodium. It's an ion or a charged particle. And it's not optional. Sodium is essential for nerve signaling, muscle contraction, and most critically, managing the amount of fluid in your blood vessels and tissues. The problem isn't the sodium itself. It's the quantity. Today, we average about eight and a half grams, roughly 17 times more than the half a gram that our ancestors generally ate. And human physiology hasn't caught up with that change.

7:29Here's the basic chain reaction. When sodium goes up, your body holds onto water to dilute the extra sodium back to a safe concentration. That extra water increases your blood volume. More volume in the same sized pipes means more pressure. That's how salt raises blood pressure, at least in principle. But there's a complication. Your body has a sophisticated regulatory system. I talked about this in my episode called Eight Glasses of Water a Day. Good guidance or urban myth. It was a fun episode. Take a listen or a realist. Anyhow, our kidneys do a great job of balancing our amount of fluid using the reenin angiotensin aldosterone system. It manages our sodium and our blood pressure. For most people, the system adjusts beautifully. You eat more salt. Your kidneys

8:35excrete more salt and blood pressure may not budge. These people are called salt resistant. And these folks are the crux of what we will explore in a few minutes. For others, our body's adjustment system doesn't work so well. Our kidneys hold on to more. Sodium blood pressure creeps up. And over time, that elevated pressure damages blood vessels, the heart, and the kidneys. These people are called salt sensitive. And the consequences worry me and should worry you. It's important to note that salt and sodium are not the same. Sodium is an element in sodium chloride. Salt is about 40% sodium by weight. So when a guideline says no more than 2,300 milligrams at sodium, that's equivalent to about 5.8 grams of salt. Roughly one teaspoon. When a food label lists sodium and milligrams, that's the number to

9:42watch. Okay, let's talk about salt intake guidelines. In the latest 2000, 26 to 2030, government food publication, the guidelines recommend that adults consume no more than 2,300 milligrams of sodium per day. Now that sounds like a lot until you put it in concrete terms. It's about one teaspoon of tablespoon for the whole day. Everything included. Now the American Heart Association goes further. Their ideal target for most adults, especially those with hypertension, diabetes, or kidney disease is 35% lower or just 1,500 milligrams per day. That's roughly 2 thirds of a teaspoon. Now here's the reality. Nearly 50% of folks are above the recommended government ceiling and double what the American Heart Association says.

10:49Now we need to talk about where the salt actually comes from. It comes from packaged, processed, or restaurant foods, not from home cooking or your salt shaker at the table. That's salt shaker, you're feeling guilty about. That's maybe 5 to 10% of your daily intake. The real culprit is your lunchtime deli meat sandwich, your afternoon soup, or your frozen dinner. Let me put some real numbers on the table, literally. Here's a quick look at sodium and foods, many of us eat regularly. Remember, the guidelines want us to limit sodium to 2,300 milligrams. Here we go. You can eat 10% of your daily allowance by eating two slices of bread, a tablespoon of ketchup, or a pinch of salt. You can eat a third of your daily allotment by eating one cup of canned chicken noodle soup and in reality, I would eat more than just one cup,

11:51or one slice of pizza, or a big mac, or half of your salt for the day with a single serving of frozen lasagna, three slices of deli ham, or a subway six-ounce cold-cut combo. So you can see that without much work, you can get to 6 to 10 grams of salt, which is what most Americans eat each day. Remember, our ancestors typically ate less than a half a gram of salt each day. Here's the good news. If you cook your own food, the amount of sodium is quite low. If you're having fresh fruit, vegetables, chicken, plain pasta, or rice, or oatmeal, there's almost no salt. You can eat all that you want, not worry about salt and cake. Of course, keep in mind these foods have calories. Sure, if you add a pinch of salt for flavoring, it will add sodium, but if they have small pinches, that won't amount to very much. And wearing my other

12:55hat, as the chef at our Madron Springs Ranch, exotic animal, bed and breakfast, I do think about this issue for our guests, and it's not just a theoretical exercise. Fortunately, pretty much everything that we serve is made from basic and yummy ingredients. Okay, there is bacon, but in general, it's pretty easy to keep salt levels low. So far, we've talked about salt in general, the national guidelines in which foods have it. But now, let's turn to our first question. Question number one. Let's say you do have high blood pressure. What is the evidence on how much salt you should eat or not eat? Now, Dr. Bobby, perhaps I don't have high blood pressure, so why should I care? Well, likely someone you love does have it, and you can tell them what you learned. Also, stay tuned to questions two and three. Back to high blood pressure or hypertension.

13:59It's common. It's too common. It's also silent, meaning you have no symptoms, and it is something to worry about and take care of. Gal and I have a phrase that we say all the time to each other, which kind of focuses our life on what matters. Here's the phrase. It's all good until it's not, and it's a fine line between the two, meaning even though everything may seem on track, change is inevitable, and from a health standpoint, we try to do what we can to avoid crossing that fine line, like suddenly having that heart attack. Ideally, we want our blood pressure below 120 over 80. From 120 to 129, it's considered elevated and becomes high blood pressure with the systolic reading is higher than 130, or the diastolic is above 80. In the US, about half

15:03of us have hypertension or high blood pressure. That's a huge number and a huge problem. Hypertension increases with age, 23% under 40, have high blood pressure, and 72% above age 60. Here are a few critical facts. Only 59% are aware that they have hypertension. Remember, I said that it's silent until it's not, or when the heart attack or stroke happens. Only half of those with hypertension are on medication for it, and only 20% get their blood pressure below 130 over 80. High blood pressure isn't just a number. It's a major contributor to heart disease, stroke, dementia, and kidney failure. Hypertension increases our risk of a heart attack or stroke by 50% in dementia and all caused death by 25%. So we care about the blood

16:06pressure and want to get it under control. The evidence is extraordinarily clear. But for today's topic, where does salt fit in? I mentioned that eating salt at least temporarily increases our body fluids and can raise the pressure in our arteries. And they're very compelling epidemiologic or population or observational data that folks who eat more salt on average have higher blood pressure. Keep this in mind on average. We will get to the concept of whether your blood pressure is sensitive to salt intake or not. But for the moment, let's say that salt does affect your blood pressure. Well, how well does lowering your sodium or salt intake reduce your blood pressure? In a study of the dash diet, which stands for dietary approaches to stop hypertension,

17:09412 patients were randomized to a high, medium, or low salt diet, where a high salt meant a typical American diet amount of 3.5 grams of sodium per day. The medium salt group ate two grams, or roughly today's guideline. And a low salt group ate one gram, which is a whole lot less than today's government or even the American Heart Association guideline. So the low salt folks had that quite restricted diet. What do they find? Reducing the salt intake from the typical high salt diet to the U.S. guideline amount led to a one to two millimeter drop in systolic blood pressure. Some, but not a huge change. Reducing the salt further to that really low level lowered the blood pressure another two to four millimeters. That had a smaller effect on diastolic blood pressure.

18:12In a broader set of studies, a meta-analysis showed that salt restriction led to about a three millimeter reduction in systolic blood pressure and a one and a half millimeter fall in diastolic blood pressure. Let's put these low salt diet findings into context and see how much medications reduce blood pressure. In a meta-analysis of 350 randomized trials or 40,000 people on treatment, taking a blood pressure drug typically lowered the systolic blood pressure by nine millimeters and five millimeters for diastolic pressure. Two to three times the impact of salt restriction. Now comes two critical questions. Is everyone equally sensitive to salt and should all of those with high blood pressure really lower their salt intake? Might I take a blood pressure pill and then

19:18enjoy salt in my food? Well, let's start with the concept of salt sensitivity. Theoretically, some of us might quickly pee out salt in our foods and not have a significant impact on our blood pressure. And others might in fact be very sensitive to salt and eating leads to sustained increases. In a lab, the way that salt sensitivity is determined is by either feeding people high salt diets or hooking them up to an IV and giving them salt in their veins. Then measure what happens to their blood pressure. Here's what we find. Some folks pee out the extra salt and others retain much of it. Keep in mind, these are artificial studies and may not fully reflect what life is like in the real world. From studies like these, we find that many of us are not salt sensitive. Salt sensitivity is more prevalent as you age in women and in people of African or Asian ancestry.

20:26So 50% or so might be salt sensitive. And perhaps another 50% or so of the population is salt resistant group. Their blood pressure doesn't respond much to dietary sodium. And it is this category that fascinates me. Perhaps those who aren't salt sensitive might be able to enjoy salt in their food. You're probably wondering, how do I know whether I am salt sensitive or not? Here we have a great tool to figure that out. You don't need to go to laboratory and get an IV full of sodium. You can do an end of one trial in yourself. That's why I call my listeners the end of one nation. Now I talk about this in detail in episode 27 called one person one study. But an end of one salt sensitivity assessment is easy to do. Step one, take your blood pressure

21:29daily or a few times a day for a week. Go to the CVS, buy yourself a home blood pressure monitor if you don't have one. They're not expensive and will be good to have in general. Step two, try a low sodium diet, definitely within the US guidelines, but perhaps even lower. Step three, for the next few weeks, check your blood pressure. Did it fall or stay about the same? Step four, add the salt back into your diet and see what happens. Step five, for further proof, you can restart the low salt diet. If your blood pressure changes a bunch when you shift from a high salt to a low salt diet, say three to five millimeters or more, then your salt sensitive and you should keep that in mind. If your blood pressure doesn't change much, perhaps one or two millimeters, then you're likely not very salt sensitive. I'm one of those folks. For the folks who

22:29aren't salt sensitive from a pure blood pressure standpoint, you can make the argument that enjoying salt in your food is okay. That's my approach, but take this with a grain of salt and talk about it with your doctor. Question number two, what about taking a blood pressure medicine to get your blood pressure under control and then not worry about the salt that you eat? That is in fact what I do. I have morning high blood pressure, which resolves on its own by the afternoon, but I did not want the high pressure in the morning, so I take Val Sartin, a common generic and pennies-a-day medication. Doing an animal and test, I found that I'm not salt sensitive. I am not sensitive to salt in my diet. So with the medication and still enjoying salt in my food, my blood pressure is under control and I enjoy my food a lot. Is this right for you?

23:31Perhaps do the salt sensitivity test and then speak with your doctor? The evidence is not definitive, but I've shared my opinion and what I do. You and your doctor can decide what's right for you. Okay, question number two, what if you have harder kidney disease? Here, it's best to be careful. Talk with your doctor, but here's a way to think about the issue. Is blood pressure the only pathway through which salt can harm you? Newer research suggests salt may also have some important non-blood pressure effects. So the evidence for how important these are and otherwise healthy people is considerably weaker. It is possible that the salt unrelated to blood pressure may impact your blood vessels in negative ways. In a combined meta-analysis of 25

24:34studies, low sodium intake was associated with 17% lower cardiovascular mortality and 12% lower overall mortality. Is this the final answer meaning salt is bad for you? Here's the problem. In these studies, it's hard to separate out the blood pressure lowering effect from other potential benefits of lower salt. It's possible that the salt effect happens through its impact on blood pressure. But salt has an impact on various salt-related hormones and potentially inflammation. But again, it's hard to separate the independent impact of salt from its impact on blood pressure. If you have heart disease or a real risk for it, best to be cautious. Talk with your doctor. Let me throw a wrench into things. It is study of 17 clinical trials.

25:35In patients with heart failure, salt restriction did not help. Outcomes were the same. So for these patients, salt didn't lead to worse outcomes. Here's another interesting study. The researchers randomized 600 villages in China. Patients had a history of a stroke or they were older than 60 and had hypertension. Some villages ate their usual foods in salt. Other villages used assault substitute of 75% sodium chloride, 25% potassium chloride. So some regular salt combined with a potassium-based salt. You can easily buy this kind of salt at the market. The research followed 21,000 people for five years. And the researchers found a 12 to 14% reduction in stroke, heart attack, or death in those villages that used the sodium and potassium salt alternative.

26:39What the study suggests is that potassium may also play a role in all of this. An assault light approach might be important. The evidence is not definitive, but adds some thoughts to the discussion. Question number three. What if you don't have high blood pressure or heart or kidney disease? Can you enjoy salt? We've now entered pretty uncharted waters from an evidence standpoint. If you want to take all precautions, by all means, lower your salt intake. Earlier, I talked about salt sensitivity. In a few studies where they compared folks with and without salt sensitivity and followed them for 10 or 20 years, there were more cardiac events in those who were salt sensitive, whether or not they had hypertension. We don't know whether they ate more salt and this was not a randomized trial. Studies like this one suggests that salt sensitivity may be important as an

27:42independent risk factor. It may be that salt's important, but that salt sensitivity is the key issue. The ultimately unanswered question. If you aren't salt sensitive, do you need to lower your salt intake? Now we're at the realm of opinion and not too much evidence. I shared with you what I do, which is that I am not salt sensitive. My blood pressure is under control with medications, and I do enjoy salt in my food. We've talked before about lifespan, health span, and joy span. Joy is important to me. That outweighs from me the uncertainty about whether everyone must reduce salt intake to low levels. Time to wrap up. Salt makes food enjoyable, and joy is a very important part of life. Salt has been associated with high blood pressure, and high blood pressure is a major risk factor for cardiovascular and other diseases.

28:46About 25 to 50% of us have salt sensitivity. You know, only way to know if you're salt sensitive is to do an end of one test in yourself. For salt sensitive folks, especially if you have high blood pressure already, being mindful of salt intake would be important. If you aren't salt sensitive, then it's less clear whether you need to limit your salt intake. Here's my call to action. Are you going to do an end of one test to see if you're sensitive to salt? If so, let me know what you learn. Life for me is about balancing risk with benefits. Should you lower your salt intake? I hope that I've given you some ways to think about this question. As always, talk with your doctor. Until next time, I hope that you can live long and well and have joy in your lives. Share what you've learned with others, and feedback to me as always. Welcome.

29:52Thanks so much for listening to Live Long and Well with Dr. Bobby. If you liked this episode, please provide a review on Apple or Spotify or wherever you listen. If you want to continue this journey or want to receive my newsletter on practical and scientific ways to improve your health and longevity, please visit me at doctorbobbylivelongandwell.com. That's doctor as in drbobbylivelongandwell.com.