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Hypercalcemia and hypocalcemia: What you need to know

From the desk of Luis Villaseñor

<p><span style="font-weight: 400">Hypercalcemia and hypocalcemia are serious medical conditions with serious consequences. If a calcium imbalance becomes severe enough, it can be life-threatening.</span></p><p><span style="font-weight: 400">Fortunately, these imbalances are relatively rare in healthy people. They aren’t everyday occurrences.</span></p><p><span style="font-weight: 400">Contrary to popular belief, insufficient dietary calcium is NOT a primary cause of hypocalcemia. When you don’t consume enough calcium, you just pillage bone to normalize serum levels.</span></p><p><span style="font-weight: 400">A similar principle applies to </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430714/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">hypercalcemia</span></a><span style="font-weight: 400">. If you consume too much dietary calcium, your body twists other dials: it increases urinary excretion, decreases gut absorption, and slows bone shedding to restore calcium to normal ranges.</span></p><p><span style="font-weight: 400">Calcium supplements are a possible exception. They can temporarily overwhelm your calcium maintenance system, spike serum calcium, and </span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC5620030/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">increase</span></a><span style="font-weight: 400"> arterial calcification. I’ll spend more time on this later.</span></p><p><span style="font-weight: 400">I’ll also explain the distinction between hypercalcemia, hypocalcemia, and calcium deficiency. By the end of the article, you’ll understand why your serum calcium is actually not a good indicator of your overall calcium status.</span></p><p><span style="font-weight: 400">First, though, I want to cover the basics of calcium and calcium imbalances. Let’s dive in.</span></p><h2><b>Calcium 101</b></h2><p><span style="font-weight: 400">Calcium is a mineral that wears many hats in the human body. These hats can be lumped into two main categories:</span></p><ol><li style="font-weight: 400"><span style="font-weight: 400">Skeletal structuring</span></li><li style="font-weight: 400"><a href="https://drinklmnt.com/blogs/health/what-are-electrolytes-and-why-are-they-important" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">Electrolyte-related roles</span></a></li></ol><p><span style="font-weight: 400">When most people think of calcium, they think of bone health. About 99% of your bodily calcium is </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK56060/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">found</span></a><span style="font-weight: 400"> in bones, teeth, and other hard tissue.</span></p><p><span style="font-weight: 400">How calcium enters and exits bone is a complex dance, and the main dancers are calcium, vitamin D, phosphorus, calcitonin, and parathyroid hormone (PTH). I’ll be referring to these nutrients and hormones throughout the article, but for now I’ll make a </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430714/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">couple of key points</span></a><span style="font-weight: 400">:</span></p><ul><li style="font-weight: 400"><span style="font-weight: 400">Adequate calcium and vitamin D levels suppress PTH, which curbs bone shedding.</span></li><li style="font-weight: 400"><span style="font-weight: 400">Vitamin D also facilitates calcium absorption in the gut.</span></li><li style="font-weight: 400"><span style="font-weight: 400">Vitamin D deficiency, calcium deficiency, and phosphorus overload elevate PTH, which in turn </span><i><span style="font-weight: 400">increases</span></i><span style="font-weight: 400"> bone shedding.</span></li><li style="font-weight: 400"><span style="font-weight: 400">Calcium overload elevates calcitonin, which shuts down calcium loss from bone.</span></li></ul><p><span style="font-weight: 400">Calcium is also an electrolyte (charged mineral) that enables cellular communication in the brain, heart, and skeletal muscles. Blood calcium plays other roles too (enzymatic activity, coagulation, etc.), but for now, understand that maintaining serum calcium levels (as opposed to maintaining bone calcium) is your body’s priority.</span></p><h2><b>What Is Hypercalcemia?</b></h2><p><span style="font-weight: 400">Hypercalcemia is </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430714/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">defined</span></a><span style="font-weight: 400"> as a serum calcium level above 10.5 mg/dL. At levels of 14.0 mg/dL and above, it’s considered a hypercalcemic crisis.</span></p><p><span style="font-weight: 400">Overt symptoms of hypercalcemia typically crop up around 12 mg/dL. Remember them with this handy rhyme: </span><i><span style="font-weight: 400">groans, bones, stones, moans, thrones, and psychic overtones</span></i><span style="font-weight: 400">.</span></p><ul><li><b>Groans</b><strong>:</strong> nausea, vomiting, stomach pain, and other GI symptoms</li><li><span style="font-weight: bold">Bones: </span>bone pain and disorders of bone density (like osteoporosis) that increase fracture risk</li><li><span style="font-weight: bold">Stones: </span>kidney stones</li><li><span style="font-weight: bold">Moans: </span>feeling low energy, lousy, and tired</li><li><span style="font-weight: bold">Thrones: </span>constipation on “the throne”</li><li><span style="font-weight: bold">Psychic overtones: </span>confusion, depression, and memory loss</li></ul><p><span style="font-weight: 400">Severe hypercalcemia can also impact heart function, leading to arrhythmias, bradycardia (slow heart rate), and other disturbances noticeable via EKG. General muscle weakness is another classic symptom.</span></p><p><span style="font-weight: 400">Although not technically a symptom, soft tissue calcification is perhaps the most insidious consequence of hypercalcemia. We want calcification to happen in the skeleton, not in the blood vessels where it </span><a href="https://pubmed.ncbi.nlm.nih.gov/30025580/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">accelerates</span></a><span style="font-weight: 400"> the progression of heart disease.</span></p><h2><b>What Causes Hypercalcemia?</b></h2><p><span style="font-weight: 400">About 1 to 2% of the general population </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430714/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">suffers</span></a><span style="font-weight: 400"> from hypercalcemia. The explanation usually ties back to PTH or vitamin D. Let’s explore that in more detail.</span></p><p><b>Causes of Hypercalcemia:</b></p><ul><li><b>Primary hyperparathyroidism</b>. A condition suffered by 0.2 to 0.8% of the population in which the parathyroid gland overproduces PTH. The common fix, unfortunately, is to remove the gland.</li><li><span style="font-weight: bold">Cancer. </span>About 2% of all cancers—including leukemia, renal carcinomas, and lymphomas—are associated with hypercalcemia. Cancer tends to disturb PTH levels.</li><li><span style="font-weight: bold">Vitamin D toxicity. </span>Excess vitamin D increases calcium absorption and spikes serum calcium levels. Most cases of vitamin D-related hypercalcemia are <a style="font-weight: bold" href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC5045493/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">seen</span></a> at 25(OH)D levels higher than 200 ng/mL.</li><li><span style="font-weight: bold">Other causes.</span> Kidney failure, use of diuretics, vitamin A toxicity, milk-alkali syndrome, and prolonged immobilization.</li></ul><p><span style="font-weight: 400">Excess calcium intake can also cause hypercalcemia, but (assuming functional calcium homeostasis) this should be a temporary situation.</span></p><h2><b>What Is Hypocalcemia?</b></h2><p><span style="font-weight: 400">Hypocalcemia is </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430912/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">defined</span></a><span style="font-weight: 400"> as serum calcium levels below 8.5 mg/dL. Though less common than hypercalcemia, it can be life-threatening if not addressed and treated with IV or oral calcium.</span></p><p><span style="font-weight: 400">The </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430912/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">symptoms</span></a><span style="font-weight: 400"> of hypocalcemia include:</span></p><ul><li style="font-weight: 400"><span style="font-weight: 400">Tetany</span></li><li style="font-weight: 400"><span style="font-weight: 400">Muscle spasms</span></li><li style="font-weight: 400"><span style="font-weight: 400">A feeling of pins and needles (paresthesias)</span></li><li style="font-weight: 400"><span style="font-weight: 400">Hand and wrist spasm (carpopedal spasm)</span></li><li style="font-weight: 400"><span style="font-weight: 400">Anxiety, depression, or mood swings</span></li><li style="font-weight: 400"><span style="font-weight: 400">Seizures</span></li><li style="font-weight: 400"><span style="font-weight: 400">Irregular heartbeat (can be fatal in severe cases)</span></li></ul><p><span style="font-weight: 400">When diagnosing hypocalcemia, clinicians look for these symptoms in conjunction with the following possible causes.</span></p><h2><b>What Causes Hypocalcemia?</b></h2><p><span style="font-weight: 400">According to NIH StatPearls, renal failure is the </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430912/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">leading cause</span></a><span style="font-weight: 400"> of hypocalcemia. When the kidneys fail, vitamin D isn’t properly metabolized and phosphorus isn’t properly excreted. This leads to lower calcium levels.</span></p><p><span style="font-weight: 400">Vitamin D deficiency is the second leading cause of hypocalcemia. When you don’t get enough D, you can’t properly absorb calcium through the intestines.</span></p><p><span style="font-weight: 400">The best sources of vitamin D are the sun, fortified dairy, and vitamin D supplements. Even though vitamin D pills are cheap, ubiquitous, and effective, about 42% of Americans are </span><a href="https://pubmed.ncbi.nlm.nih.gov/21310306/#:~:text=Vitamin%20D%20deficiency%20was%20defined,followed%20by%20Hispanics%20(69.2%25)." target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">deficient</span></a><span style="font-weight: 400">.</span></p><p><span style="font-weight: 400">Other possible causes of hypocalcemia </span><a href="https://www.ncbi.nlm.nih.gov/books/NBK430912/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">include</span></a><span style="font-weight: 400">:</span></p><ul><li style="font-weight: 400"><span style="font-weight: 400">Hypomagnesemia or hypermagnesemia (high or low serum </span><a href="https://drinklmnt.com/blogs/health/magnesium-benefits-and-best-sources" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">magnesium</span></a><span style="font-weight: 400">)</span></li><li style="font-weight: 400"><span style="font-weight: 400">Low parathyroid hormone (PTH) due to parathyroidectomy, autoimmunity, or various conditions that affect the parathyroid gland. Remember, PTH helps shuttle calcium out of bone and into the blood.</span></li><li style="font-weight: 400"><span style="font-weight: 400">Alkalosis (calcium levels depend on serum pH)</span></li><li style="font-weight: 400"><span style="font-weight: 400">Acute pancreatitis</span></li><li style="font-weight: 400"><span style="font-weight: 400">Sepsis</span></li><li style="font-weight: 400"><span style="font-weight: 400">Phosphorus overload</span></li><li style="font-weight: 400"><span style="font-weight: 400">Drugs that increase bone reabsorption of calcium or decrease PTH secretion. (The chemotherapeutic drug Cisplatin can also cause hypocalcemia.)</span></li><li style="font-weight: 400"><span style="font-weight: 400">Osteoblastic metastases</span></li></ul><p><span style="font-weight: 400">Why isn’t low dietary calcium listed? Let’s discuss.</span></p><h2><b>Calcium Imbalance vs Calcium Deficiency</b></h2><p><span style="font-weight: 400">A calcium imbalance is distinct from a calcium deficiency. This is a critical point.</span></p><p><span style="font-weight: 400">A calcium imbalance occurs when serum calcium levels get too high (hypercalcemia) or too low (hypocalcemia). This imbalance will show up on a blood test and often requires medical attention.</span></p><p><span style="font-weight: 400">A calcium deficiency occurs when you don’t consume enough calcium. There are consequences, but they typically aren’t acute and/or life-threatening like with </span><a href="https://drinklmnt.com/blogs/health/how-to-prevent-an-electrolyte-imbalance-and-what-causes-them" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">electrolyte imbalances</span></a><span style="font-weight: 400">.</span></p><p><span style="font-weight: 400">The main </span><a href="https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">consequence</span></a><span style="font-weight: 400"> of calcium deficiency is poor bone density and increased fracture risk. (Osteoporosis). Why? Because bone is your body’s calcium reservoir.</span></p><p><span style="font-weight: 400">When you consume sufficient calcium, the reservoir stays full. When you don’t, the reservoir gets depleted to maintain serum calcium.</span></p><p><span style="font-weight: 400">The way your body looks at it, serum calcium is ALWAYS the priority. Serum calcium regulates basic functions like muscle contraction, neural transmission, heartbeat, blood clotting, and more. These functions are not optional. As you’ll recall, things get pretty hairy when serum levels fluctuate.</span></p><p><span style="font-weight: 400">Bone calcium plays second fiddle to serum calcium. Osteoporosis is a progressive degeneration; not a survival emergency.</span></p><p><span style="font-weight: 400">The takeaway? A serum calcium test DOES NOT validly assess calcium status. It just tells you that your calcium regulation system is working.</span></p><h2><b>Getting Your Daily Calcium</b></h2><p><span style="font-weight: 400">For healthy bones, adults should aim for around a gram of calcium per day. Teenagers and postmenopausal women need a bit more, and young children a bit less. See this </span><a href="https://ods.od.nih.gov/factsheets/Calcium-HealthProfessional/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">fact sheet</span></a><span style="font-weight: 400"> for exact doses.</span></p><p><span style="font-weight: 400">I advise getting all of your daily calcium from dietary sources. Skip the supplements.</span></p><p><span style="font-weight: 400">I already mentioned why: calcium supplements create a temporary state of hypercalcemia that drives soft tissue calcification. They’re </span><a href="https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC5620030/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">linked</span></a><span style="font-weight: 400"> to increased heart disease risk. Dietary calcium, however, is less likely to overload your calcium disposal system.</span></p><p><span style="font-weight: 400">Are you getting enough dietary calcium? To find out, log your meals for one to three days in the </span><a href="https://cronometer.com/" target="_blank" rel="noopener noreferrer"><span style="font-weight: 400">Cronometer app</span></a><span style="font-weight: 400">. You’ll get a good sense of your daily calcium intake.</span></p><p><span style="font-weight: 400">If you need more calcium, eat more dairy, soft bones (best found in canned fish), and cruciferous vegetables. But you may not need more calcium. We analyzed thousands of</span><span style="font-weight: 400"> people eating whole foods diets, and most of them were getting plenty.</span></p><p><span style="font-weight: 400">That’s one reason we didn’t put calcium in </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">, our electrolyte drink mix. On top of that, we had lingering concerns about calcium supplements, calcification, and heart health.</span></p><p><span style="font-weight: 400">Before you get back to your day, I want to reinforce a point I’ve made several times throughout this article because it’s important: calcium intakes are mostly unrelated to serum calcium levels. Hypercalcemia and hypocalcemia are caused by other factors.</span></p><p><span style="font-weight: 400">I hope this article helped clear up some key information about calcium for you!</span></p>