Sodium: What It Actually Does in Your Body, and How Much Is Too Much

The mineral behind every food label warning, explained without the scare tactics.

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By the Ration Editorial Team · Reviewed against primary research · Updated July 14, 2026

Sodium is a mineral and an electrolyte. It carries a positive charge and works closely with potassium and chloride to keep your body's fluids balanced.

Most dietary sodium comes from salt, which is sodium chloride. Salt is about 40 percent sodium by weight.

Your body cannot make sodium, so it has to come from food. Unlike many nutrients, the challenge for most people is getting less of it, not more.

Sodium helps regulate how much water your body holds onto, which directly affects blood volume and blood pressure.

It also plays a central role in nerve signaling. Nerve cells use a sodium-potassium pump to generate the electrical impulses that let your brain talk to your muscles and organs.

• Maintains fluid balance inside and outside cells
• Supports transmission of nerve impulses
• Enables muscle contraction, including the heart muscle
• Helps the small intestine absorb nutrients like glucose and amino acids
• Works with chloride and bicarbonate to help regulate blood pH

Physiologically, the body needs only a small amount of sodium each day to function, often estimated at around 500 mg.

Health authorities generally recommend keeping intake under about 2,300 mg per day for most adults, roughly the amount in one teaspoon of salt.

Despite that guidance, average intake in many countries with heavily processed food supplies runs well above this limit, often in the 3,400 to 4,000 mg range.

Some people, including those with high blood pressure, kidney disease, or a family history of hypertension, are often advised to aim lower, sometimes closer to 1,500 mg per day.

The relationship between sodium and blood pressure has been studied for decades, largely through clinical trials and long-term observational cohorts.

In general, reducing sodium intake tends to lower blood pressure, though the effect size varies a lot between individuals. Some people are described as salt sensitive, meaning their blood pressure responds strongly to changes in sodium intake, while others show little change.

Older adults, people with existing hypertension, and people of African descent tend to show greater blood pressure sensitivity to sodium on average.

The picture is less settled at the extremes. Some observational research has suggested a J-shaped curve, where both very low and very high sodium intakes are associated with worse cardiovascular outcomes, which has fueled debate among researchers about the ideal target for otherwise healthy people.

Potassium intake matters alongside sodium. Diets richer in potassium, from foods like bananas, potatoes, and beans, appear to blunt some of sodium's effect on blood pressure.

Table salt is the most obvious source, but it is not the main one for most people. The bulk of dietary sodium in modern diets comes from processed and restaurant food, not home cooking.

• Bread and rolls
• Cold cuts and cured meats
• Pizza
• Soups, canned or packaged
• Sandwiches and burgers
• Cheese
• Savory snacks like chips and pretzels
• Poultry with sodium-containing marinades or brines
• Condiments like soy sauce, ketchup, and salad dressing
• Canned vegetables and vegetable juices

Naturally occurring sodium in whole foods like fruits, vegetables, plain meat, and dairy is relatively low. The jump happens during processing, curing, and food preparation for shelf life and flavor.

Low sodium, known clinically as hyponatremia, is uncommon from diet alone but can occur in specific situations.

• Heavy, prolonged sweating during endurance exercise without electrolyte replacement
• Certain diuretic medications
• Excessive fluid intake relative to sodium loss, sometimes seen in endurance athletes
• Kidney or adrenal conditions that affect sodium regulation
• Severe vomiting or diarrhea

Symptoms of low sodium can include headache, confusion, nausea, muscle cramps, and in severe cases, seizures. This is a medical condition that needs clinical attention, not something to self-manage with food choices.

Chronically high sodium intake is most consistently linked with elevated blood pressure, which over time raises the risk of stroke, heart disease, and kidney problems.

High sodium diets have also been associated with an increased risk of stomach cancer in some population studies, though this research is observational and other dietary factors, like intake of cured or pickled foods, likely play a role too.

For people with heart failure or kidney disease, excess sodium can worsen fluid retention and swelling, which is why these groups are often given stricter sodium targets.

• People with high blood pressure or a family history of it
• People with chronic kidney disease
• People with heart failure, where fluid retention is a concern
• Older adults, who tend to show greater blood pressure sensitivity to sodium
• Anyone eating a diet heavy in packaged, fast, or restaurant food

Sodium is essential for nerve function, muscle contraction, and fluid balance, and your body genuinely needs some of it every day.

For most people eating a typical modern diet, the practical issue is getting too much, mostly from processed and restaurant foods rather than the salt shaker at home.

Paying attention to labels, cooking more meals from whole ingredients, and pairing sodium intake with plenty of potassium-rich foods are reasonable, low-risk steps for most people.