RHR: Shaking Up the Salt Myth

In this episode we discuss:

• How the anti-salt movement began
• Major studies that challenge the narrative
• Why sodium is essential
• Potential downsides of sodium restriction
• Who should actually reduce sodium
• The overlooked role of potassium
• Tips for choosing a salt and practical takeaways

Show notes:

• “Associations of urinary sodium excretion with cardiovascular events in individuals with and without hypertension: a pooled analysis of data from four studies” by Mente, A., et al.
• “Urinary sodium and potassium excretion and risk of cardiovascular events” by O’Donnell, M. J., et al.
• “Fatal and nonfatal outcomes, incidence of hypertension, and blood pressure changes in relation to urinary sodium excretion” by Stolarz-Skrzypek, K., et al.
• “Shaking Up The Salt Myth” series by Kresser, C.
• Learn more about the Adapt Naturals Core Plus bundle, or take our quiz to see which products best suit your needs
• If you’d like to ask a question for Chris to answer in a future episode, submit it here
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Hey everybody, Chris Kresser here. Welcome to another episode of Revolution Health Radio. Today we’re going to tackle something that almost every patient I saw in my years of clinical practice had been told at some point: eat less salt. If you’ve ever had a doctor hand you a low-sodium handout, or read a health headline in the last 30 years, you’ve absorbed the message. Salt raises blood pressure, high blood pressure causes heart attacks and strokes, therefore salt is dangerous. The American Heart Association recommends 1500 milligrams of sodium per day for most people, a number so low it’s genuinely difficult to achieve, even when you’re trying. I spent years digging into the scientific literature behind that recommendation – the original research that launched the low salt movement in the 1970s, the major prospective studies that followed, and some findings that have been largely ignored by mainstream public health. What I found was not what I expected, and I think it will surprise you too.

This isn’t a simple story, and I’m not here to tell you sodium is harmless at any dose. But I do think most people are missing critical context about how the salt dogma was established, what the strongest research actually says, and what that means for how you should approach salt in your own diet. Let’s dive in.

How the Anti-Salt Movement Began

The story of how salt became public enemy number one in nutrition has a familiar shape. It follows the same arc as several other chapters in dietary history. A compelling initial hypothesis, early data that seemed to support it, and a public health machine that moved faster than the science could sustain. The central figure is Lewis Dahl, a physician at Brookhaven National Laboratory who studied salt and blood pressure through the 1960s and 70s. Dahl’s best-known experiment involved feeding rats an extraordinary amount of sodium – the equivalent for a human of more than 500 grams of sodium per day, which is roughly 50 times the average Western intake. At those doses, hypertension reliably appeared. Dahl drew the conclusion that high salt intake causes high blood pressure, and from there, the policy cascade began. The inferential leap from ‘massive doses induce toxicity in rats’ to ‘moderate human intake causes cardiovascular disease’ should have been more scrutinized than it was. But the finding landed in fertile soil. It aligned with the intuition of the era’s public health establishment, and it was politically convenient. Sodium was something people could be told to reduce without requiring structural changes to the food system.

Dahl also conducted cross-cultural research, plotting salt consumption against blood pressure rates across different populations around the world. Some Japanese communities with famously high salt intake had elevated rates of hypertension. Some isolated indigenous populations eating almost no added salt had very low blood pressure. The correlation looked persuasive on a scatter plot. But the INTERSALT Study, the largest and most methodologically rigorous cross cultural investigation of this question ever undertaken, complicated that picture considerably. When researchers analyzed the data while controlling for confounding variables, the association between salt intake and blood pressure largely disappeared. The tribal populations with the lowest blood pressure also happened to be lean, physically active, free of processed food and eating dramatically different diets in virtually every other respect. Attributing their blood pressure to sodium intake while ignoring everything else is a textbook example of confounded data being over-interpreted.

In 1998, science journalist Gary Taubes wrote a landmark piece for Science magazine documenting the tension between the evidence and the policy. He described how the data supporting universal salt restriction had never been compelling, and how the scientific community’s internal dissent had been consistently drowned out by public health messaging. That article was published over 25 years ago. The recommendations have barely changed since. What we ended up with was a nutritional policy launched on flawed extrapolations from animal studies and confounded epidemiology, institutionalized before the evidence could be adequately tested, and then maintained largely by inertia. This is how dietary myths are made and why they’re so difficult to dislodge, even when better evidence arrives.

Major Studies That Challenged the Narrative

Two major studies published in JAMA in 2011 set off a genuine debate within cardiology about whether the conventional wisdom on salt could be sustained. The first, led by O’Donnell and colleagues, drew on data from the ONTARGET and TRANSCEND trials, nearly 29,000 participants with established cardiovascular disease or diabetes, followed for a median of 56 months. The researchers estimated 24-hour urinary sodium excretion, the most reliable available proxy for actual sodium intake, and examined outcomes across the distribution. What they found was a clear J-shaped curve. Compared to participants excreting four to six grams of sodium per day, those excreting more than seven grams did have meaningfully increased cardiovascular risk, including higher rates of cardiovascular death, heart attack, stroke, and hospitalization for heart failure. But those excreting less than three grams per day, approximately the level recommended by major health organizations, also had higher cardiovascular mortality and higher rates of congestive heart failure hospitalization. The lowest risk sat in the middle. That’s what we mean by a J-shaped curve.

The second JAMA study, by Stolarz-Skrzypek and colleagues, was a European cohort of nearly 3700 people followed for almost eight years. The findings went even further. Lower sodium excretion was independently associated with higher cardiovascular mortality, and in this population, baseline sodium excretion did not predict who would develop hypertension over time. The blood pressure effects of sodium in the study were real but modest, and they did not translate into increased hypertension incidents or worse cardiovascular outcomes. Both studies generated significant pushback from public health authorities who argued that the participants were already ill, that the follow up periods were too short, or that the methodology was flawed. Some of that criticism had merit. But the pattern they documented, with risk rising at both ends of the sodium distribution, is hard to dismiss, and it was replicated in the largest analysis ever conducted on this question.

That analysis was published in The Lancet in 2016 by Mente, O’Donnell, and colleagues, drawing on pooled data from four large prospective cohort studies spanning 133,000 individuals across 49 countries. The findings confirmed the J- or U-shaped association at scale. Low sodium intake, below three grams per day was associated with increased cardiovascular risk and mortality, regardless of whether the person had hypertension. High sodium intake above seven grams per day was also associated with increased risk, but only in people who already had hypertension. In normotensive individuals, people with normal blood pressure, high sodium did not significantly elevate risk even above seven grams per day. The analysis also found that higher potassium excretion was independently associated with reduced stroke risk across all groups, a finding that we’ll come back to when we talk about practical recommendations. The authors concluded that their data supported targeted sodium restriction for hypertensive populations with high intake, not universal sodium restriction across all adults. That conclusion is a long way from the current AHA recommendation of 1500 milligrams for most Americans.

For decades we’ve been told to cut salt to protect our hearts. But what if the science tells a different story? In this episode of Revolution Health Radio, we break down the research behind sodium guidelines and explain why both too much and too little salt may increase cardiovascular risk. #ChrisKresser #salt

Why Sodium Is Essential

It helps to understand the physiology here, because the biological picture is fully consistent with what the research shows. Sodium is not a dietary villain that snuck into the food supply. It’s an essential electrolyte with fundamental biological roles. Along with its counterpart chloride, sodium is the primary driver of fluid distribution in the extracellular space. Meaning it regulates how water moves in and out of your cells. It’s critical for transmitting nerve impulses, for muscle contraction including the heart, and for maintaining acid-base balance throughout the body. You can’t sustain life without it. When sodium intake drops, the kidneys don’t simply shrug and adapt. They activate a powerful compensatory system, the renin-angiotensin-aldosterone system, or RAAS. This cascade releases hormones that signal the kidneys to retain sodium and water, constricting blood vessels in the process. It’s physiologically effective in the short run, but it isn’t a neutral adaptation. Chronic RAAS activation is associated with elevated blood pressure through a different mechanism, and with higher circulating levels of renin, aldosterone, cholesterol and triglycerides. Research has confirmed that people on low-sodium diets develop these adverse hormonal and lipid changes, effects that may offset or reverse any blood pressure benefit from the sodium restriction itself.

Potential Downsides of Sodium Restriction

There’s also a connection between sodium restriction and insulin sensitivity that doesn’t get nearly enough attention. Research has shown that low-sodium diets can induce acute worsening of insulin sensitivity, meaning that restrictions severe enough to please the AHA may be actively undermining metabolic health for some people, particularly those at risk for Type II diabetes. Elderly people are at particular risk from aggressive sodium restriction. Hyponatremia, abnormally low blood sodium, is common in older adults, especially those who are hospitalized or acutely ill, and it’s associated with falls, hip fractures, and measurable cognitive decline. Applying universal sodium restriction guidelines to a population that may already be struggling to maintain sodium balance creates real clinical risk. Athletes and highly active individuals represent another important exception. Studies of endurance athletes have found that a meaningful proportion develop hyponatremia, low sodium, even without obvious symptoms. In one study of Boston Marathon finishers, 13 percent were hyponatremic at the finish line. In some other endurance events, the reported incidence has been as high as almost 30 percent. At the severe end of the spectrum, hyponatremia can cause cerebral edema and is potentially fatal. The idea that sodium is something to be minimized at all costs breaks down immediately when you account for the biology.

Who Should Actually Reduce Sodium

Given all this, I want to be precise about who may actually benefit from reducing sodium, because the answer matters. The key concept is salt sensitivity. Some individuals experience a meaningful blood pressure rise when sodium intake increases. Others show very little or no response. This distinction has major implications for how recommendations should be applied. Research suggests that roughly half of people with diagnosed hypertension are salt-sensitive, while among people with normal blood pressure, the figure is closer to 25 percent. Salt sensitivity appears to be driven largely by impaired sodium handling in the kidneys, and has a significant genetic component. For salt-sensitive hypertensives, particularly those in the high-intake range documented in the research, sodium reduction is likely to produce meaningful blood pressure benefit. The Lancet analysis makes this reasonably clear. For the rest of the population, salt insensitive people with normal blood pressure, which is a large majority of adults, the blood pressure benefit of severe sodium restriction is modest at best, or non-existent, and it may come with the metabolic costs described above.

The Overlooked Role of Potassium

There’s an important wrinkle to the salt sensitivity story. Potassium intake plays a substantial role in modulating blood pressure and salt sensitivity. Research has found that increasing dietary potassium within the normal physiological range can suppress salt sensitivity dose-dependently. For some people who appear to be salt-sensitive, the more important intervention may be increasing potassium rather than cutting sodium. The Lancet findings on potassium and stroke risk reinforce this point.

This leads to a broader structural issue with the modern diet that I think deserves far more attention than sodium restriction does. Estimates of ancestral potassium intake run as high as 10,500 milligrams, or 10.5 grams per day. The current American average is roughly 2500 milligrams, or 2.5 grams – a quarter of that. We’ve been running a population-wide potassium deficit for generations, and the sodium-to-potassium ratio of the modern diet is wildly out of alignment with what our kidneys evolved to process. Addressing that imbalance by eating more potassium-rich whole foods is likely more protective for most people than obsessing over the salt shaker.

Beyond salt sensitivity, there are specific clinical conditions where some degree of sodium moderation is supported by evidence. People with chronic kidney disease and reduced glomerular filtration rates, or eGFR, have more difficulty excreting sodium, and high intake can accelerate progression in some cases, though this is highly individual and depends on the type and severity of disease. People with a history of kidney stones have evidence that higher sodium excretion increases urinary calcium excretion, which may contribute to stone formation. These are real clinical considerations. They simply apply to defined subpopulations, not to everybody.

So what does this all translate to practically? Based on the research, a reasonable target for most adults is between three and seven grams of sodium per day, which corresponds to roughly 1.5 to 3.5 teaspoons of salt. This is the range consistently associated with the lowest cardiovascular risk across the major perspective data. It’s also not far from where global human sodium consumption has historically been. Analysis of salt intake patterns over the past two centuries suggests that people around the world have tended to consume in this range naturally, which is at least consistent with the idea that human sodium appetite regulates toward a physiologically appropriate level. People who are highly active, sweat heavily, or live in hot climates will likely need to be on the higher end of that range. Less active individuals with no complicating conditions will likely be comfortable on the lower end. Athletes, especially those doing prolonged endurance exercise, need to be particularly attentive to replacing sodium loss through sweat. The most important practical lever for most people is not how much salt you add to your cooking, it’s whether you’re eating processed foods. About 75 percent of American sodium intake comes from processed and packaged food, not the salt shaker. When you shift to a whole foods diet and cook from scratch, you dramatically reduce your background sodium load, and you can then add salt to taste without worrying about overshooting. Your body is fairly good at regulating toward its preferred intake when it isn’t being overwhelmed by the sodium levels typical of processed food.

Tips For Choosing a Salt and Practical Takeaways

On the question of what type of salt to use, refined table salt is heavily processed, stripped of most naturally occurring minerals, and commonly contains additives like anti-caking agents. Unrefined options like sea salt, Himalayan pink salt, or domestic alternatives like Real Salt from Utah, contain small amounts of trace minerals including calcium, potassium, magnesium, and zinc. The mineral content of these salts is not large enough to represent a meaningful nutritional contribution on its own, but they are less processed and free of additives, which make them preferable. One important note if you’re switching away from iodized table salt – iodine. Table salt has historically been a significant iodine source for many Americans, and iodine deficiency is a real concern. If you move entirely to uniodized natural salts, make sure you’re getting iodine from other sources like sea vegetables, cod and other white fish, and dairy.

The broader takeaway is that sodium doesn’t operate in isolation. Its effects on blood pressure and cardiovascular risk are deeply intertwined with potassium status, overall dietary quality, kidney function, activity level, and genetic variation. A useful framework is: eat whole foods, don’t fear unrefined salt in your cooking, make sure your diet is rich in potassium from vegetables and other whole food sources, and work with a clinician if you have specific conditions that warrant individual assessment.

The salt story is a useful lens for a broader pattern in nutrition science – an early policy intervention, launched on imperfect evidence, scaled up to affect hundreds of millions of people, and then maintained in the face of mounting contradictory research because institutional momentum is a powerful force. In the same 50 years that Americans have been told to eat less salt, average sodium intake has barely moved, and the chronic diseases the policy was meant to prevent have worsened. The problem was never sodium in isolation. It was a food environment that stripped potassium, magnesium, and whole-food context out of the diet while blaming the salt shaker. The research supports a grounded, proportionate approach. Cut processed food, eat a potassium-rich whole foods diet, don’t restrict salt for its own sake, and apply targeted reductions for the specific conditions where the evidence actually supports them.

Thanks for listening. You can find show notes and links to all the studies I mentioned at ChrisKresser.com. If you have any questions about this episode or suggestions for future topics, head over to ChrisKresser.com/PodcastQuestion and leave a message. I read all of them, and your questions help shape the content I create. Until next time, be well.