The seven main electrolytes in your body are sodium, potassium, calcium, magnesium, chloride, bicarbonate, and phosphate. These are minerals that carry an electrical charge when dissolved in your blood and other body fluids, and they control everything from your heartbeat to the strength of your bones.
Sodium
Sodium is the most abundant electrolyte in your blood and the fluid surrounding your cells. Its primary job is regulating how much water your body holds onto. When sodium levels rise, your body retains water to dilute it; when they drop, you lose fluid. This is why salty meals leave you feeling bloated and thirsty. Sodium also plays a direct role in nerve signaling and muscle contraction. Normal blood levels fall between 135 and 145 mmol/L.
Most people get far more sodium than they need from processed foods, restaurant meals, bread, and cured meats. The concern with sodium is rarely deficiency from diet. Instead, levels can drop dangerously (a condition called hyponatremia) from excessive sweating, prolonged vomiting or diarrhea, or drinking very large amounts of water without replacing salts.
Potassium
Potassium works as a counterpart to sodium. While sodium dominates the fluid outside your cells, potassium concentrates inside them. Together, they create an electrical gradient across every cell membrane, which is the basic mechanism your body uses to fire nerve impulses and contract muscles. After each nerve signal, a cellular pump uses energy to push three sodium ions out and pull two potassium ions back in, resetting the cell so it’s ready to fire again. Your heart depends on this cycle for every beat.
Normal blood potassium ranges from 3.6 to 5.5 mmol/L. When levels fall too low, you may notice muscle weakness, cramping, fatigue, or an irregular heartbeat. The FDA recommends 3,400 mg of potassium per day for men and 2,600 mg for women, and most people fall short.
Some of the richest food sources may surprise you. A cup of cooked beet greens delivers 1,309 mg of potassium, and a cup of cooked Swiss chard provides 961 mg. A medium baked potato with skin has more than 900 mg, and a cup of cooked lima beans contains 969 mg. Other strong sources include acorn squash (896 mg per half cup cooked), spinach (839 mg per cup cooked), yogurt (up to 625 mg per cup), and avocados (364 mg per half). A medium banana, the food most associated with potassium, has about 451 mg.
Calcium
Calcium is best known for building and maintaining bones and teeth, which store about 99% of the body’s supply. But the remaining 1% circulating in your blood is just as critical. When your nervous system signals a muscle to contract, calcium floods into the muscle fibers to trigger the contraction. Once the movement is complete, calcium gets pumped back out so the muscle can relax. This cycle happens in every skeletal muscle, in the smooth muscle lining your blood vessels, and in your heart.
Normal blood calcium for adults is 8.8 to 10.7 mg/dL. Dairy products, fortified plant milks, leafy greens like kale and bok choy, canned sardines (with bones), and tofu made with calcium sulfate are all reliable dietary sources.
Magnesium
Magnesium is involved in over 300 enzyme reactions, but its most noticeable role is regulating how calcium behaves inside your muscles. Without enough magnesium, calcium can accumulate in muscle fibers and cause prolonged contraction, which is one reason magnesium deficiency often shows up as muscle cramps, twitches, or spasms. Magnesium also supports nerve function, helps regulate blood pressure, and plays a part in blood sugar control.
Normal blood levels range from 1.5 to 2.6 mg/dL. Good dietary sources include pumpkin seeds, almonds, spinach, black beans, dark chocolate, and whole grains. Magnesium deficiency is relatively common because modern diets tend to be heavy in processed foods that have had their magnesium stripped out during refining.
Chloride
Chloride typically travels with sodium (table salt is sodium chloride) and helps regulate fluid balance and blood pressure. It also forms a key part of stomach acid, which your body needs to break down food and kill bacteria. Because chloride so closely follows sodium, people who get enough salt in their diet rarely run low on chloride. Levels can drop with prolonged vomiting, since stomach acid is rich in chloride. Normal blood chloride ranges from 97 to 105 mmol/L.
Bicarbonate
Bicarbonate is your body’s main acid buffer. Blood pH needs to stay in a tight range (roughly 7.35 to 7.45), and bicarbonate is the primary system that keeps it there. When something makes your blood more acidic, bicarbonate neutralizes the acid by converting it into carbonic acid, a much weaker acid that can be exhaled as carbon dioxide through your lungs. Under normal conditions, bicarbonate outnumbers carbonic acid in your blood by a ratio of about 20 to 1, giving the system a large capacity to absorb acid before pH shifts dangerously.
Your kidneys fine-tune bicarbonate levels by either conserving it or letting it pass into urine. Unlike other electrolytes on this list, you don’t get bicarbonate directly from food. Your body produces it internally, and the lungs and kidneys work together to keep the supply balanced.
Phosphate
Phosphate partners with calcium to mineralize bones and teeth, giving them their rigid structure. Beyond the skeleton, phosphate is a building block of DNA and a component of the molecule your cells burn for energy (ATP). It also contributes to the body’s pH buffering system alongside bicarbonate. Phosphate is found in protein-rich foods like meat, poultry, fish, dairy, nuts, and legumes, and deficiency from diet alone is uncommon.
How Electrolytes Work Together
No single electrolyte acts alone. Sodium and potassium maintain the electrical charge across cell membranes that makes nerve signaling possible. Calcium triggers a muscle contraction, and magnesium helps end it. Chloride follows sodium to balance fluid. Bicarbonate and phosphate both buffer pH. When one electrolyte shifts out of range, it often drags others with it, which is why doctors typically check a panel of several electrolytes at once rather than testing just one.
Common Causes of Imbalance
Electrolyte levels shift whenever your body gains or loses fluid quickly. Heavy sweating during exercise or heat exposure depletes sodium, potassium, and chloride. Vomiting and diarrhea can drain all of these plus bicarbonate. Certain medications, particularly diuretics, deliberately increase urination and can lower potassium and magnesium. Kidney disease disrupts the organs responsible for fine-tuning every electrolyte, and chronic conditions like diabetes can affect multiple levels at once.
Mild imbalances often cause vague symptoms: fatigue, muscle cramps, headaches, dizziness, or an irregular heartbeat. More severe shifts can lead to confusion, seizures, or dangerous heart rhythm changes. For most healthy people, eating a varied diet with plenty of vegetables, fruits, legumes, and dairy or fortified alternatives supplies enough of every electrolyte. If you lose significant fluid through intense exercise, illness, or heat, replacing both water and electrolytes (through food, broth, or an electrolyte drink) is more effective than water alone.