High sodium can refer to two things: too much sodium in your diet or too much sodium in your blood. Most people searching this term want to know how much sodium is too much and why it matters. The short answer is that adults should consume less than 2,300 milligrams of sodium per day, roughly one teaspoon of table salt. The average person eats well above that, and the excess raises blood pressure and increases the risk of heart disease, stroke, and kidney damage over time.
High Sodium in Your Diet
Sodium is a mineral your body needs in small amounts to maintain fluid balance, transmit nerve signals, and keep muscles working properly. The problem is quantity. The Dietary Guidelines for Americans set the daily limit at 2,300 milligrams for adults, with even lower limits recommended for children under 14. Most Americans consume roughly 3,400 milligrams per day, nearly 50% more than recommended.
Sodium and salt are related but not identical. Table salt is about 40% sodium by weight, so 5 grams of salt (a teaspoon) contains around 2,000 milligrams of sodium. When you’re reading a nutrition label, the number listed is sodium, not salt. If a single serving of soup contains 800 milligrams of sodium, that’s already more than a third of your entire daily budget.
Where Most Sodium Comes From
The salt shaker on your table isn’t the main culprit. Most dietary sodium comes from processed and restaurant foods, often in places you wouldn’t expect. The CDC identified the top sources of sodium in the average diet:
- Breads and rolls, which don’t taste salty but add up across multiple servings per day
- Cold cuts and cured meats, like deli turkey, bacon, and salami
- Pizza, which combines salty dough, cheese, sauce, and cured toppings
- Poultry, particularly processed or pre-seasoned varieties
- Soups, especially canned versions, which can contain over 1,000 milligrams per serving
A single slice of bread may contain 100 to 200 milligrams of sodium. That’s modest on its own, but if you eat bread at every meal, it becomes one of your largest sodium sources simply through volume. This is why tracking sodium requires looking at the full picture of your diet rather than avoiding one or two obviously salty foods.
How Sodium Raises Blood Pressure
When you eat more sodium than your body needs, your kidneys work to filter out the excess. But the process isn’t instant. In the meantime, the extra sodium pulls water into your bloodstream through osmosis, increasing the total volume of fluid your blood vessels have to carry. More fluid means higher pressure against your artery walls.
Your kidneys respond by increasing their filtration rate to push out the extra sodium and water, but this compensatory system has limits. In people who are “salt-sensitive,” meaning their blood pressure responds more strongly to sodium intake, the kidneys can’t fully compensate. Blood pressure stays elevated, and over time the blood vessels themselves tighten in response to the sustained pressure increase. This creates a cycle where high sodium intake leads to higher blood pressure, which leads to stiffer blood vessels, which makes pressure harder to bring down. Roughly 30 to 50% of people with high blood pressure are considered salt-sensitive, along with a smaller percentage of people with otherwise normal readings.
Long-Term Health Risks
The damage from a chronically high-sodium diet extends well beyond blood pressure. An analysis of Global Burden of Disease data from 1990 to 2021 identified eight diseases attributed to high-sodium diets. Ranked by disease burden, the most significant are stroke, ischemic heart disease, hypertensive heart disease, stomach cancer, chronic kidney disease, atrial fibrillation, aortic aneurysm, and peripheral arterial disease in the legs.
The link to stomach cancer may surprise people. Excess sodium appears to help the bacterium H. pylori colonize the stomach lining, a well-established risk factor for gastric cancer. High-sodium diets also promote cancer progression through increased inflammation and changes to gut bacteria.
Chronic kidney disease is another serious consequence. Globally, an estimated 45,530 deaths per year are attributed to kidney disease caused by high sodium intake. The connection likely works through several pathways: high sodium drives up blood pressure, which damages the kidney’s delicate filtering structures, and it may also increase consumption of sugary drinks and contribute to obesity, both independent risk factors for kidney disease.
High Sodium in the Blood
High blood sodium, called hypernatremia, is a different condition from simply eating too much salt. Normal blood sodium levels fall between roughly 136 and 145 milliequivalents per liter. Symptoms of hypernatremia typically appear when levels rise rapidly or exceed 160 mEq/L, and they primarily affect the brain and nervous system.
The most common cause is dehydration, not dietary salt. When your body loses more water than sodium, through prolonged vomiting, diarrhea, excessive sweating, or not drinking enough fluids, the concentration of sodium in your blood rises. Certain conditions like diabetes insipidus, where the body produces unusually large volumes of dilute urine, also cause it. Older adults and infants are at higher risk because they may not be able to recognize or communicate thirst effectively.
Symptoms of High Blood Sodium
Early signs include intense thirst and reduced urine output. As levels climb, symptoms shift to the nervous system: confusion, irritability, muscle twitching, and exaggerated reflexes. In infants, the signs can be subtler, often showing up as unusual fussiness, a high-pitched cry, or increasing sleepiness. Severe cases can progress to lethargy and loss of consciousness. The skin may feel unusually doughy or velvety because cells have lost water to the surrounding fluid.
Hypernatremia is typically caught through a routine blood test and is most common in hospitalized patients, very young children, and older adults. It’s distinct from the slow, cumulative damage of a high-sodium diet, which rarely causes blood sodium to go above normal. Your kidneys are remarkably good at maintaining sodium balance in the blood even when your dietary intake is excessive. The problem with too much dietary sodium isn’t that blood levels spike, but that the extra work of processing all that sodium takes a toll on your cardiovascular system and kidneys over years and decades.
How to Identify High-Sodium Foods
Nutrition labels list sodium in milligrams per serving. As a quick rule of thumb, 5% of your daily value (about 115 milligrams per serving) is considered low, while 20% or more (460 milligrams or above) is high. Pay close attention to serving sizes: a can of soup might list 800 milligrams per serving but contain two or two and a half servings per can.
Foods that taste salty, like chips and pretzels, are obvious sources. The trickier ones are foods that don’t register as salty at all: bread, breakfast cereals, condiments like ketchup and soy sauce, cottage cheese, and frozen meals. Even sweet baked goods can contain significant sodium because salt enhances flavor and acts as a preservative. Comparing brands of the same product can reveal surprisingly large differences. One brand of canned tomatoes might have three times the sodium of another, with no noticeable taste difference.
Choosing fresh or frozen vegetables without added sauces, cooking at home more often, and rinsing canned beans or vegetables before using them are simple ways to cut sodium without overhauling your entire diet. Your taste buds adjust within a few weeks of reducing sodium intake, and foods that once tasted normal will start to taste noticeably salty.