Salt raises blood pressure, stiffens arteries, strains the kidneys, and pulls calcium from bones. The core problem is sodium, which makes up about 40% of table salt. Your body needs a small amount of sodium to function, but most people consume far more than that, and the excess triggers a chain of effects that quietly damages the cardiovascular system, kidneys, stomach, and skeleton over time.
How Sodium Raises Blood Pressure
When you eat more sodium than your body needs, the kidneys respond by holding onto water to keep the concentration of sodium in your blood stable. This extra fluid increases the total volume of blood flowing through your vessels. More blood pushing against artery walls means higher blood pressure. Your body has built-in sensors in the heart, blood vessels, and kidneys that detect rising blood volume and signal the kidneys to flush out the excess sodium. But when sodium intake stays consistently high, those corrective systems can’t fully keep up.
The hormone aldosterone plays a central role. It tells your kidneys to retain sodium and shed potassium. When aldosterone is elevated and sodium intake is high, less urine gets produced, blood volume climbs, and blood pressure rises further. Over months and years, this sustained pressure damages blood vessel walls, thickens the heart muscle, and increases the risk of heart attack and stroke.
Artery Damage Beyond Blood Pressure
High sodium doesn’t just push harder on your arteries. It changes the arteries themselves. Research published in the Proceedings of the National Academy of Sciences found that when sodium levels in the blood rise within the normal range, the cells lining blood vessel walls become stiffer, increasing by more than 22% in stiffness when aldosterone is present. Stiffer arteries are less able to flex with each heartbeat, which compounds the stress on the cardiovascular system.
At the same time, elevated sodium reduces the production of nitric oxide, a molecule that tells blood vessels to relax and widen. With less nitric oxide available, arteries stay constricted. This combination of stiffer vessel walls and reduced ability to dilate means that high salt intake damages arteries through at least two pathways that operate independently of blood pressure itself.
Salt Sensitivity Varies Widely
Not everyone’s blood pressure responds to sodium the same way. Roughly 60% of people with high blood pressure are considered “salt sensitive,” meaning their blood pressure rises and falls noticeably with changes in sodium intake. The remaining 40% show a blunted response, which can create a false sense of security. Even in people whose blood pressure doesn’t spike from a salty meal, the arterial stiffening, kidney strain, and calcium loss still occur. Salt sensitivity has a genetic component and tends to increase with age.
Kidney Strain and Long-Term Damage
Your kidneys filter sodium out of the blood all day long. When intake is consistently high, this workload accelerates wear on the filtering units inside the kidneys. A large study tracking thousands of people found that for every additional gram of salt consumed daily, the risk of developing impaired kidney function rose by about 4.5%. People eating an average of 11.5 grams of salt per day had a 29% higher risk of kidney impairment compared to those eating about 6 grams. The incidence of kidney problems was roughly 50% higher in the high-salt group (26.5 versus 17.8 cases per 1,000 person-years).
This kidney damage occurs independently of blood pressure. In other words, even if your blood pressure stays normal, chronically high salt intake still degrades kidney filtration over time. And as kidney function declines, the kidneys become less efficient at excreting sodium, creating a feedback loop that makes the problem progressively worse.
Effects on the Stomach Lining
Excess salt directly irritates the mucosa, the protective lining of the stomach. Over time, this irritation promotes chronic inflammation and can lead to a condition called atrophic gastritis, where the stomach lining thins and its glands deteriorate. High-salt diets also create a more hospitable environment for Helicobacter pylori, the bacterium linked to stomach ulcers and gastric cancer. Salt encourages the colonization and expansion of particularly aggressive strains of H. pylori, amplifying chronic inflammation and accelerating precancerous changes in stomach tissue. High salt intake also increases oxidative stress, which damages cellular DNA and further drives the process toward cancer.
Calcium Loss and Bone Thinning
Sodium and calcium share the same transport pathways in the kidneys. When sodium intake is high, the kidneys excrete more calcium along with it. In postmenopausal women, high-sodium diets increased urinary calcium loss by about 29 milligrams per day compared to lower-sodium diets. That may sound modest, but sustained over years, it adds up. Women with habitual sodium intake above 3.5 grams per day (roughly 9 grams of salt) showed 5 to 10% greater calcium excretion and elevated markers of bone breakdown.
When the body loses too much calcium through urine, the parathyroid glands compensate by pulling calcium from bones to keep blood levels stable. This accelerates bone thinning and increases the risk of osteoporosis, particularly in older adults and postmenopausal women who are already losing bone density.
The Sodium-Potassium Connection
Sodium doesn’t act in isolation. Potassium, found in fruits, vegetables, beans, and dairy, counterbalances many of sodium’s effects by helping blood vessels relax and encouraging the kidneys to excrete sodium. What matters for cardiovascular health is not just how much sodium you eat, but the ratio of sodium to potassium in your diet. A higher sodium-to-potassium ratio is significantly associated with increased cardiovascular risk. Most people eating a modern diet get too much sodium and too little potassium, pushing that ratio in the wrong direction.
How Much Is Too Much
The World Health Organization recommends less than 2,000 milligrams of sodium per day for adults, equivalent to just under a teaspoon of salt (5 grams). The American Heart Association’s 2025 guidelines set the upper limit at 2,300 milligrams, with an ideal target of no more than 1,500 milligrams for most adults, particularly those managing high blood pressure. Most Americans consume well over 3,400 milligrams daily.
The gap between guidelines and reality exists largely because over 70% of dietary sodium comes from packaged and prepared foods, not from the salt shaker at home. Bread, deli meats, canned soups, frozen meals, condiments, cheese, and restaurant food are the primary sources. Cutting back on salt means reading labels and shifting toward whole, minimally processed foods rather than simply putting down the salt shaker.