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Electrolytes and heart health: A science-based guide

From the desk of Robb Wolf

<p>When it comes to heart health, some electrolytes are controversial. Others, not so much. Potassium is not controversial. Higher potassium intakes are unarguably linked to lower blood pressure. Since high blood pressure is a primary factor contributing to heart disease risk, we like that.</p><p><span style="font-weight: 400">Regarding potassium, the FDA </span><a href="https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">says</span></a> <span style="font-weight: 400">“Diets containing foods that are a good source of potassium and that are low in sodium may reduce the risk of high blood pressure and stroke.”</span></p><p><span style="font-weight: 400">Wait&#8230; did you catch the low in sodium part? Here’s where things DO get controversial.</span> <span style="font-weight: 400">The US government recommends capping sodium intake at 2.3 grams per day.</span></p><p><span style="font-weight: 400">This is, allegedly, a heart-healthy move. Until the past decade or so, it’s been taken as gospel.</span> However,<span style="font-weight: 400"> in the majority of cases, sodium restriction doesn’t do the heart any favors. We have</span><a href="https://pubmed.ncbi.nlm.nih.gov/22110105/" target="_blank" rel="noopener noreferrer"> <span style="font-weight: 400">data</span></a><span style="font-weight: 400"> suggesting that, when sodium intake goes down (under 2.3 grams), bad cardiovascular outcomes may actually increase.</span></p><p><span style="font-weight: 400">Today I want to cover the clinical research behind electrolytes and heart health. Sodium is the star here, but minerals like potassium and magnesium play important roles too in heart function, blood pressure, and more.</span> <span style="font-weight: 400">Later, I’ll give recommendations for electrolyte intake through diet and supplementation. Most people aren’t getting enough, and I’d like to see that change.</span></p><p><span style="font-weight: 400">Of course, I’ll never have the pull that the FDA has. But maybe if I squawk loudly and frequently enough, it’ll start a groundswell. And that groundswell will slowly shift the anti-salt sentiment.</span> <span style="font-weight: 400">How did this sentiment start, anyway?</span></p><h2><strong>Why Low Sodium Is Considered “Heart Healthy”</strong></h2><p><span style="font-weight: 400">Most people haven’t heard of Lewis Dahl. He was a scientist that ran a number of sodium-related studies back in the 60s and 70s.</span></p><p><span style="font-weight: 400">His most famous experiments featured rats (now called “Dahl rats”) that were genetically prone to </span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2118645/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">salt sensitivity</span></a><span style="font-weight: 400">. When Dahl fed these rats high-sodium diets, they developed—predictably enough—high blood pressure, or hypertension.</span></p><p><span style="font-weight: 400">The sodium &#8211; blood pressure link appeared to be supported by a smattering of population data. But the data was inconsistent. Many big salt eaters, for instance, weren’t hypertensive. Was it possible that something else (not sodium) was driving the correlation?</span></p><p><span style="font-weight: 400">The question was never properly addressed. Instead, the 1980 US government began warning its citizens to avoid sodium.</span></p><p><span style="font-weight: 400">Today these warnings are enshrined in official recommendations. We’re told to consume under 2.3 grams of sodium per day, per the FDA—and even less (1.5 grams) if you heed the American Heart Association’s advice.</span></p><p><span style="font-weight: 400">And so the salt shaker has become a pariah. Salt has become a public enemy, right up there with sugar and cigarettes.</span></p><p><span style="font-weight: 400">Is sodium’s reputation deserved? Let’s see what the evidence has to say.</span></p><h2><strong>Sodium and Heart Disease Risk</strong></h2><p><span style="font-weight: 400">In most hospitals, heart patients are fed low-sodium diets. This is meant to reduce blood pressure, and therefore bad outcomes like heart attack and stroke.</span> <span style="font-weight: 400">But a </span><a href="https://pubmed.ncbi.nlm.nih.gov/22110105/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">2011 study published in JAMA</span></a><span style="font-weight: 400">—one of the most prestigious journals on the planet — suggests this policy is misdirected.</span></p><p><span style="font-weight: 400">The study followed nearly five thousand patients with preexisting heart disease or diabetes for close to five years. Researchers tracked their sodium excretion (as a proxy for sodium consumption), and compared it with rates of stroke and heart attack after the five-year follow up.</span></p><p><span style="font-weight: 400">The results should surprise sodium cynics. The patients at the lowest sodium intakes (in line with government recommendations) had higher rates of stroke and heart attack than patients at more moderate intakes of about 4–6 grams of daily sodium. You had to reach about 8 grams of sodium before the risk spiked up again.</span></p><p><span style="font-weight: 400">And this result occurred in the very folks — high risk patients — that low-sodium diets are supposed to help. Well, they didn’t help.</span> <span style="font-weight: 400">I know what you’re thinking. </span><i><span style="font-weight: 400">That’s just one study&#8230; It doesn’t prove low sodium diets aren’t heart healthy.</span></i></p><p><span style="font-weight: 400">That’s right. It’s important to look at </span><i><span style="font-weight: 400">systematic reviews</span></i><span style="font-weight: 400"> — or papers that compile the literature on a given topic.</span> <span style="font-weight: 400">One such </span><a href="https://jamanetwork.com/journals/jamainternalmedicine/article-abstract/2712563?guestAccessKey=8d6f8001-a1f8-4372-b8b9-a7d935d5d7a4&amp;utm_source=silverchair&amp;utm_medium=email&amp;utm_campaign=article_alert-jamainternalmedicine&amp;utm_content=olf&amp;utm_term=110518" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">review</span></a><span style="font-weight: 400">, published in JAMA in 2018, looked at nine clinical studies that asked one question: Does restricting salt help with heart failure?</span></p><p><span style="font-weight: 400">Across the literature, the evidence was “inconclusive.” In other words, there isn’t a good case for sodium restriction in heart failure patients.</span> <span style="font-weight: 400">But what about sodium driving up blood pressure? Surely there’s something to that.</span></p><h2><strong>Sodium and Blood Pressure</strong></h2><p><span style="font-weight: 400">One of sodium’s primary functions is to increase fluid volume in your blood vessels. This helps get blood to your brain (among other places), and it’s a big reason why low serum sodium brings a host of cognitive symptoms.</span></p><p><span style="font-weight: 400">So yes. Boost your sodium intake high enough, and you will increase blood volume enough to raise blood pressure.</span> <span style="font-weight: 400">But how does this play out in the real world, where real people are consuming varying amounts of sodium?</span></p><p><span style="font-weight: 400">To answer this question we turn to the 1988 </span><a href="https://pubmed.ncbi.nlm.nih.gov/3416162/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">Intersalt Study</span></a><span style="font-weight: 400">, which analyzed over 10,000 people across the globe to explore the link between dietary sodium and blood pressure. The punchline? In most populations, there was no link between salt consumption and hypertension.</span></p><p><span style="font-weight: 400">More </span><a href="https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.31.1_supplement.446.6" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">recent research</span></a><span style="font-weight: 400"> has strengthened this finding. Researchers wondered: What happens when you take a few thousand people with normal blood pressure, and see where they fall on the sodium intake / blood pressure graph?</span></p><p><span style="font-weight: 400">The result was a doozy. Those at lower sodium intakes (under 2.5 grams) had HIGHER blood pressure than those at higher sodium intakes. If sodium was driving hypertension, how could this result happen?</span></p><h2><strong>Potassium and Blood Pressure</strong></h2><p><span style="font-weight: 400">Okay, that was my sodium rant. Now I need to talk about potassium, because it’s all tied up in this blood pressure question.</span></p><p><span style="font-weight: 400">Potassium, like sodium, helps regulate fluid balance inside and outside your cells. This keeps your blood flowing through your veins, your brain suspended in fluid, and — yes — your blood pressure within healthy ranges.</span></p><p><span style="font-weight: 400">Higher potassium intakes are uncontroversially </span><a href="https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">associated</span></a><span style="font-weight: 400"> with lower blood pressure, yet only <a href="https://www.ncbi.nlm.nih.gov/books/NBK545438/#:~:text=The%2075th%20percentile%20of%20usual%20potassium%20intake%20exceeds%20the%20potassium%20AI%20for%20most%20adult%20DRI%20age%2C%20sex%2C%20and%20life%2Dstage%20groups%2C%20indicating%20that%20between%20one%2Dquarter%20and%20one%2Dhalf%20of%20U.S.%20and%20Canadian%20adults%20exceed%20the%20AI%20(see%20Table%207%2D4)." target="_blank" rel="noreferrer noopener">20–40%</a> of US Americans consume the daily <a href="https://www.ncbi.nlm.nih.gov/books/NBK587683/" target="_blank" rel="noreferrer noopener">adequate intake</a> of 3.4 grams for men and 2.6 grams for women. Not to mention, optimal intakes may sit closer to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181280/" target="_blank" rel="noreferrer noopener">3.5–5 grams</a> of potassium each day. This contributes to higher blood pressure and increased heart disease risk, and this increased risk is blamed on sodium. Let me explain how.</span></p><p><span style="font-weight: 400">Think about the Standard American Diet (SAD), infamous for causing the metabolic problems that drive heart disease. The SAD is a high sodium diet, it’s true. (Processed foods are oftentimes salty foods.) But it’s also high in sugar and low in potassium-rich fruits and vegetables.</span> <span style="font-weight: 400">People who eat more salt are also </span><a href="https://www.ahajournals.org/doi/full/10.1161/hypertensionaha.107.100990" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">more likely</span></a><span style="font-weight: 400"> to drink sugary beverages — a confounding factor that makes sodium look bad.</span></p><p><span style="font-weight: 400">Potassium is the other big confounder. High salt generally means low potassium, which is bad news for blood pressure. But in the context of a high-potassium diet, there’s no evidence that moderate sodium intakes (4–6 grams per day) increase the risk of hypertension.</span></p><h2><strong>Magnesium and Heart Health</strong></h2><p><span style="font-weight: 400">Tribute must now be paid to magnesium, a mineral which literally helps regulate the beating of your heart. Magnesium also </span><a href="https://pubmed.ncbi.nlm.nih.gov/29793664/#:~:text=Magnesium%20also%20has%20a%20role,the%20pathogenesis%20of%20cardiovascular%20disease." target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">influences</span></a><span style="font-weight: 400"> blood vessel relaxation, calcification, clotting, and even inflammation.</span></p><p><span style="font-weight: 400">Inflammation is a key driver of atherosclerosis, the process underlying heart disease. Specifically, inflammatory particles like cytokines and macrophages contribute to the formation of plaque in the arteries. When these plaques eventually break off, a heart attack or stroke can occur.</span></p><p><span style="font-weight: 400">By modulating this immune-driven process, magnesium may modulate heart disease risk. This is </span><a href="https://www.nature.com/articles/1601689" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">evidenced</span></a><span style="font-weight: 400"> by the fact that magnesium deficient patients have higher levels of systemic inflammation.</span></p><p><span style="font-weight: 400">Magnesium supplementation is also a </span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6025730/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">promising therapy</span></a><span style="font-weight: 400"> for alleviating cardiac arrhythmia, a condition in which the heart doesn’t beat properly.</span></p><p><span style="font-weight: 400">According to one estimate, up to 30% of people are </span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">subclinically deficient</span></a><span style="font-weight: 400"> in magnesium.</span></p><p><span style="font-weight: 400">But since it’s difficult to assess magnesium status in the blood, I suspect deficiency rates are even higher. These hidden magnesium deficiencies likely contribute to the high rates of heart disease we see in society.</span></p><h2><strong>Optimizing Electrolytes For Heart Health</strong></h2><p><span style="font-weight: 400">Every electrolyte has a sweet spot for health. Although our best numbers look at population based recommendations, it’s important to note that individual needs and tolerances will be a big factor.</span></p><p><span style="font-weight: 400">Just as a quick aside: the half life of caffeine (how long it takes the body to metabolize half a dose of caffeine) is, on average, 8 hours. Yet, it is well understood that some people can metabolize the same in 4 hours, while others take 36!</span></p><p><span style="font-weight: 400">These ranges are still unclear for many electrolytes. So, when it comes to optimal electrolyte amounts and ratios, rest assured — what you need may be different than what your neighbor needs.</span></p><p><span style="font-weight: 400">For sodium, the sweet spot appears to hang around <a href="https://pubmed.ncbi.nlm.nih.gov/22110105/" target="_blank" rel="noopener">4–6 grams</a> per day. For potassium, it’s about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6181280/" target="_blank" rel="noopener">3.5–5 grams</a> per day. And for magnesium, it’s around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5786912/" target="_blank" rel="noopener">400–600 mg</a> per day.</span></p><p><span style="font-weight: 400">Most of your potassium and magnesium should come from dietary sources. This means eating dark leafy vegetables, starchy tubers, meat, and fruits. </span><span style="font-weight: 400">If you’re on a low-carb or keto diet, fruit is limited, so you’ll need to double down on dark leafy greens like spinach and kale to get enough electrolytes.</span></p><p><span style="font-weight: 400">Keto or not, I recommend folks supplement with 1 gram of potassium and about 300 mg magnesium per day in addition to dietary sources. The harder part is hitting 4–6 grams of sodium.</span></p><p><span style="font-weight: 400">I created </span><a href="https://drinklmnt.com/products/lmnt-recharge-electrolyte-drink" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">LMNT</span></a><span style="font-weight: 400"> to help folks hit these science-based sodium, potassium, and magnesium targets without all the heaping sugar content found in traditional &#8220;sports drinks.&#8221;</span></p><p><span style="font-weight: 400">In case you were wondering, I didn’t put calcium in LMNT because calcium deficiency is more rare. Plus there’s some </span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5121484/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">evidence</span> </a><span style="font-weight: 400">that calcium supplements increase arterial calcification.</span></p><p><span style="font-weight: 400">Anyways, however you get your electrolytes — from diet, LMNT, homebrews, or ad hoc supplements — I hope that you do. Your heart will be healthier for it.</span></p>