Does sodium cause water retention?

Written by Robb Wolf (opens in a new tab)

I get asked a lot if <a href="https://drinklmnt.com/products/lmnt-recharge-electrolyte-drink" rel="noopener noreferrer" target="_blank">LMNT</a> will cause bloating. The concern is that the hit of salt will cause fluid retention and swelling.My answer? It depends. Water retention is complicated stuff, though the root cause rarely comes back to ONLY <a href="https://drinklmnt.com/blogs/health/is-sodium-good-or-bad-for-you" rel="noopener noreferrer" target="_blank">sodium</a>.I realize the conventional wisdom is that too much salt makes you bloated—and when is conventional wisdom ever wrong? But the truth is, we see this primarily in salt-sensitive folks, and/or those with chronically elevated insulin levels.These folks see a mild, transient increase in blood pressure when they consume salt. They also tend to retain more water than the general population. The problem is impaired sodium excretion.Salt-sensitive people retain ANY amount of dietary sodium, so playing “hide the salt shaker” doesn’t address the underlying issue of what’s driving the retention. The cause of salt sensitivity varies by person.In many cases, it stems from dysfunctional kidneys—the organs responsible for excreting sodium through urine. Salt-sensitive folks also <a href="https://pubmed.ncbi.nlm.nih.gov/9607376/" rel="noopener noreferrer" target="_blank">tend</a> to be insulin resistant. Again, the root cause here isn’t sodium; it’s a metabolic issue.Diet, lifestyle, and metabolic health are highly relevant in many cases of bloating. If someone hits the fried shrimp platter after a few piña coladas, they’re likely to become a bit more inflamed than they’d like to be. Many will even feel “puffy” afterward.And, believe it or not, swelling can also be a sign of low sodium. In these cases, the remedy is simple: increase your <a href="https://drinklmnt.com/blogs/health/does-salt-help-with-hydration" rel="noopener noreferrer" target="_blank">salt</a> intake!Today I’ll be doing a deep dive into this question of sodium, salt sensitivity, and water retention. I hope it provides you clarity on the long-debated topic!<h2>What Happens When You Consume Lots of Salt?</h2>Most human bodies are remarkably effective at maintaining sodium levels. This sodium regulation system is the same system that <a href="https://drinklmnt.com/blogs/health/what-electrolytes-do-for-you" rel="noopener noreferrer" target="_blank">regulates fluid balance</a> for proper blood flow, skin moisture, and waste management.Let’s look at four ways fluid balance may be disrupted and how the our system handles them:<h3>#1: Consuming too much sodium</h3>People worry that sodium will make them retain water like a sponge. But beyond cases of salt sensitivity (I’ll cover them soon), that’s not how it works.When you consume an excess of salt, your body works hard to get rid of it. For instance, the hormones aldosterone, renin, angiotensin, and antidiuretic hormone (ADH) are <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951800/" rel="noopener noreferrer" target="_blank">suppressed</a>—an action that increases sodium excretion through urine.High salt intakes also increase thirst. (These chips are making me thirsty!). Drinking water restores blood sodium levels to normal ranges, and any excess fluid is excreted through urine.<h3>#2: Not consuming enough sodium</h3>If you’re light on sodium, your sodium retention hormones <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3951800/" rel="noopener noreferrer" target="_blank">come out to play</a>. These include:<ul><li>Renin</li><li>Angiotensin</li><li>Aldosterone</li><li>Antidiuretic hormone</li><li>Epinephrine</li><li>Norepinephrine</li></ul>The problem is, these hormones don’t just tell the kidneys to hold onto sodium. They also constrict your blood vessels and increase blood pressure.This probably explains why sodium-restricted diets are <a href="https://faseb.onlinelibrary.wiley.com/doi/abs/10.1096/fasebj.31.1_supplement.446.6" rel="noopener noreferrer" target="_blank">linked</a> to higher blood pressures in many people. It sounds counterintuitive, but it makes sense when you begin to learn more about fluid balance. Sodium leads to increased fluid volume, so if sodium intake is inadequate, one compensatory mechanism is a tightening of blood vessels.<h3>#3: You drink too much water</h3><a href="https://drinklmnt.com/blogs/health/can-you-drink-too-much-water" rel="noopener noreferrer" target="_blank">Drinking too much sodium-free water</a> is probably the biggest mistake athletes make. It’s why so many competitors suffer headaches, confusion, dizziness, brain fog, and even brain damage or death from the low sodium levels known as exercise-associated <a href="https://drinklmnt.com/blogs/health/hyponatremia" rel="noopener noreferrer" target="_blank">hyponatremia</a>.These cases often require oral or intravenous sodium to remedy. But in milder cases of overhydration (drinking 8 glasses of plain water per day, say) the body simply pulls the needed sodium from bone. This bumps up blood sodium levels, but it’s <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4880174/" rel="noopener noreferrer" target="_blank">bad news</a> for bone density.<h3>#4: You don’t drink enough water</h3>Aside from elderly people with mobility issues or those with faulty thirst mechanisms, most people are consuming enough (or too much) fluids. When we need more fluids, we get thirsty. That’s why healthy people are <a href="https://www.ncbi.nlm.nih.gov/books/NBK555956/" rel="noopener noreferrer" target="_blank">rarely dehydrated</a>.That being said, I have heard of people who just dislike drinking water. If you ever go a whole day without drinking water, you should reconsider your hydration strategy. Soda doesn’t count, folks.<h2>Salt Sensitivity and Water Retention</h2>Some percentage of the population (perhaps over <a href="https://www.ahajournals.org/doi/full/10.1161/01.hyp.27.3.481" rel="noopener noreferrer" target="_blank">half the hypertensive population</a>) retains sodium far beyond what their bodies actually need. These people are lumped together under the umbrella diagnosis of salt sensitivity.By one <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724405/" rel="noopener noreferrer" target="_blank">standard</a>, a person is considered salt-sensitive if their blood pressure rises by at least 5 mmHg after consuming salt. This criterion isn’t super helpful because it doesn’t specify how much salt is needed to raise the bp (that figure will vary by individual), but it still provides a rough guideline.Rising blood pressure is the signature of salt sensitivity, but these folks also tend to see increased fluid retention (bloating) after taking on sodium. This results from an altered sodium retention system.The most obvious cause of salt sensitivity is chronic kidney disease. If kidney function is impaired, sodium excretion <a href="https://pubmed.ncbi.nlm.nih.gov/22898905/" rel="noopener noreferrer" target="_blank">gets impaired too</a>. That’s partly why black people experience higher rates of salt sensitivity than white people — they are nearly <a href="https://www.niddk.nih.gov/health-information/kidney-disease/race-ethnicity" rel="noopener noreferrer" target="_blank">four times</a> more likely to develop end-stage kidney disease. Not surprisingly, <a href="https://pubmed.ncbi.nlm.nih.gov/27707707/" rel="noopener noreferrer" target="_blank">chronic kidney disease and insulin resistance</a> track closely.If you dig deeper, you also find that salt-sensitive folks have an overstimulated renin-angiotensin-aldosterone system. Remember these hormones? They help you retain sodium.But they also cause vasoconstriction and <a href="https://drinklmnt.com/blogs/health/does-potassium-help-lower-blood-pressure" rel="noopener noreferrer" target="_blank">high blood pressure</a>. This explains, in part, why you see higher rates of hypertension in salt-sensitive folks. It’s not the salt, but the broken salt regulation hormones.That’s only half the story though.<h2>The Link to Insulin Resistance</h2>When someone is insulin resistant, they’re more likely to be salt-sensitive. This isn’t just something I’ve noticed anecdotally—it’s <a href="https://pubmed.ncbi.nlm.nih.gov/9607376/" rel="noopener noreferrer" target="_blank">well-established</a> in the literature.Insulin resistance refers to the inability of the hormone insulin to properly regulate blood sugar levels. As a result, blood sugar is left in circulation (leading to dangerously high blood sugar) or stored as fat.Insulin resistance is at the heart of type 2 diabetes, a condition marked by high blood sugar, high insulin, high triglycerides, high blood pressure, and obesity. Folks with type 2 diabetes also tend to over-retain sodium.But cutting down on sodium isn’t the optimal answer. As you’ll recall, sodium-restricted diets can also raise blood pressure.The best answer to this problem involves a diet and lifestyle overhaul geared towards normalizing insulin function and blood pressure. This overhaul may mean:<ul><li>Eating a low-carb or ketogenic diet to lose weight, lower blood sugar, and help <a href="https://drinklmnt.com/blogs/health/the-keto-diet-for-diabetics" rel="noopener noreferrer" target="_blank">reverse insulin resistance</a>. It’s important to do this with medical supervision. On a low-carb diet, a patient can end up with a dangerous case of low blood sugar, or hypoglycemia, if not properly supervised.</li><li>Adopting an <a href="https://drinklmnt.com/blogs/health/fasting-what-you-need-to-know" rel="noopener noreferrer" target="_blank">intermittent fasting program</a> to achieve similar goals. Again, supervised by a medical professional.</li><li>Exercising regularly. Strength training, moderate cardio, and high-intensity interval training (HIIT) have all <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5569266/" rel="noopener noreferrer" target="_blank">been shown</a> to improve insulin sensitivity. Staying active also boosts sodium losses through sweat.</li><li>Managing stress levels at home and on the job. (Easier said than done, but I’ve found that daily physical activity is SUPER helpful here).</li><li>Sleeping 7 to 9 hours per night. (This helps with stress too).</li></ul>I’ve helped more than a few folks with similar overhauls, and I’ve noticed a trend: fix the metabolism and you often improve the salt sensitivity.I’ve also noticed that people often mistake low sodium symptoms for salt sensitivity symptoms.<h2>The Swelling Could Be Low Sodium</h2>When someone complains of swollen hands or feet, I don’t immediately assume they’re salt-sensitive. Yes, it could be insulin resistance or kidney issues driving sodium retention, but it could also be a sodium deficiency.I have a few questions to sort things out. Are you exercising and sweating frequently? When you <a href="https://drinklmnt.com/blogs/health/how-to-stay-hydrated" rel="noopener noreferrer" target="_blank">rehydrate</a>, is it with plain water? Are you consciously limiting salt intake?If I hear more than one “yes”, I know the swelling could be due to a lack of sodium. And the remedy isn’t to consume less salt, but more. It’s an essential mineral, after all.This is a common scenario at the beach. Not only is it hot and humid, but folks are swilling water, beer, and other sodium-free liquids in a misguided effort to stay hydrated.If someone blames salt retention for the swelling, they may <a href="https://drinklmnt.com/blogs/health/how-much-water-should-you-drink-a-day-a-science-based-guide-to-hydration" rel="noopener noreferrer" target="_blank">drink more water</a> to clear it out. But that won’t work. It will only exacerbate low sodium symptoms.So how do you stay hydrated at the beach? Just like you stay hydrated in other sweaty situations: <a href="https://drinklmnt.com/blogs/health/electrolyte-water-benefits-and-best-sources" rel="noopener noreferrer" target="_blank">Drink electrolyte water</a> to thirst.This simple practice replaces both sodium and fluids lost through sweat. I created <a href="https://drinklmnt.com/products/lmnt-recharge-electrolyte-drink" rel="noopener noreferrer" target="_blank">LMNT</a> to be a tasty, convenient, sugar-free way to make this happen.<h2>Will LMNT Make You Bloated?</h2>In most cases, it won’t. Active people, low-carbers, and those who practice fasting need the extra sodium for <a href="https://drinklmnt.com/blogs/health/do-electrolytes-give-you-energy" rel="noopener noreferrer" target="_blank">better energy</a>, fewer muscle cramps, and clearer cognition.But as with any nutrient, it’s possible to overdo sodium. This is especially true for insulin-resistant folks, those eating lots of super processed foods, and those who live a sedentary lifestyle. These folks are more likely to be salt sensitive due to their lifestyle’s effects on their metabolism, and so they will likely see some water retention at higher salt intakes.The long-term solution, however, isn’t to ban sodium. That won’t end any better. The solution is to fix the underlying metabolic issues.If you or someone you know is striving to level up their health, check out <a href="https://join.thehealthyrebellion.com/" rel="noopener noreferrer" target="_blank">The Healthy Rebellion</a>. It’s a community dedicated to helping folks lose weight, feel better, and liberate themselves from the sick care system. We hope to see you around!