Sodium raises blood pressure by pulling extra water into your bloodstream, forcing your heart to work harder and damaging blood vessels over time. The global average intake is about 4,310 mg per day, more than double the World Health Organization’s recommendation of less than 2,000 mg. That gap between what people eat and what’s considered safe explains why excess sodium is one of the most widespread dietary risk factors for heart disease, stroke, and other chronic conditions.
How Sodium Affects Your Blood Vessels
Sodium’s most immediate effect is on fluid balance. Your kidneys regulate how much sodium stays in your body, and when levels climb, they signal your body to hold onto water to keep sodium concentration stable. That extra fluid increases blood volume, which raises the pressure inside your arteries. Over time, this sustained pressure damages vessel walls and strains the heart.
But the damage goes beyond simple fluid mechanics. Research published in the Proceedings of the National Academy of Sciences found that rising sodium levels in the blood directly stiffen the cells lining your arteries. When sodium enters these endothelial cells, they swell and lose their flexibility. That stiffness reduces their ability to produce nitric oxide, a molecule that relaxes blood vessels and keeps them open. The result: arteries that can’t dilate properly, which drives blood pressure even higher. This effect kicks in within the normal blood sodium range (between 135 and 145 millimoles per liter), meaning even modest increases in sodium can begin to impair vascular function.
Not Everyone Responds the Same Way
About 30% of otherwise healthy people are considered “salt sensitive,” meaning their blood pressure rises more sharply in response to sodium than the average person’s. Among people who already have high blood pressure, that figure jumps above 50%. Salt sensitivity is more common in women than men, and it increases with age. Conditions like diabetes and kidney disease also make salt sensitivity more likely.
Salt sensitivity is considered an independent risk factor for cardiovascular disease and death. That means even if your blood pressure numbers look acceptable, being salt sensitive still increases your risk. There’s no simple home test for it, but if you have a family history of high blood pressure or fall into one of the higher-risk groups, reducing sodium intake carries outsized benefits.
Heart Disease, Stroke, and Stomach Cancer
The connection between sodium and cardiovascular disease is the most well-established risk. Chronically elevated blood pressure damages artery walls, promotes plaque buildup, and increases the likelihood of heart attack and stroke. The American Heart Association estimates that for most people, cutting sodium by just 1,000 mg per day can meaningfully improve blood pressure and heart health.
Less widely known is sodium’s link to stomach cancer. A meta-analysis of 38 case-control studies covering more than 37,000 people found that high salt intake was associated with a 55% increased risk of gastric cancer compared to low salt intake. Salt damages the protective mucous lining of the stomach, which can make cells more vulnerable to cancer-causing agents over time.
Sodium and Bone Loss
Excess sodium also affects your bones. When your kidneys flush out sodium, calcium gets pulled along with it. The more sodium you consume, the more calcium you lose through urine. People with high blood pressure lose even more calcium per unit of sodium than those with normal blood pressure, and they tend to have higher levels of parathyroid hormone, which pulls calcium from bones to compensate. Over years, this pattern can weaken bone density, particularly in women.
Why Potassium Matters as Much as Sodium
Your body doesn’t process sodium in isolation. Potassium works as a counterbalance, helping your kidneys excrete sodium, relaxing blood vessel walls, and blunting the effects of a high-sodium meal. Research tracking the sodium-to-potassium ratio found that all-cause mortality begins trending upward once daily sodium intake exceeds about 1.2 times your potassium intake by weight. The WHO recommends keeping the ratio below 0.6 mg sodium per mg potassium, though most people eating a typical Western diet far exceed that.
Increasing potassium intake significantly reduces mortality risk in people with high blood pressure. Potassium stimulates the kidneys to excrete more sodium, improves the function of the cells lining your blood vessels, and promotes arterial relaxation. Fruits, vegetables, beans, and potatoes are the richest sources. In practical terms, eating more produce may be just as important as cutting back on salty foods.
Where the Sodium Actually Comes From
Over 70% of the sodium in the average American diet comes from packaged and restaurant foods, not from the salt shaker at home. According to the CDC, about 40% of sodium consumed comes from just a handful of categories: deli meat sandwiches, pizza, burritos and tacos, soups, salty snacks like chips and crackers, poultry dishes, pasta dishes, burgers, and egg dishes. Bread, cheese, and condiments also contribute heavily because people eat them so frequently, even though a single serving may not seem particularly salty.
This is why simply avoiding the salt shaker doesn’t move the needle much. Reading nutrition labels is far more effective. The American Heart Association recommends no more than 2,300 mg of sodium per day, with an ideal target of 1,500 mg for most adults. The average American consumes over 3,300 mg daily.
Can You Get Too Little Sodium?
Sodium is an essential nutrient. Your nerves and muscles depend on it, and your body needs some to maintain fluid balance. Blood sodium below 135 mmol/L is a condition called hyponatremia, which can cause confusion, nausea, seizures, and in severe cases, can be life-threatening. This typically happens not from eating too little salt but from drinking excessive amounts of water, especially during endurance exercise like marathons or triathlons, where heavy sweating depletes sodium and large fluid intake dilutes what remains.
For the vast majority of people eating a modern diet, getting too little sodium is not a realistic concern. The risk almost always tilts in the other direction.