Salt is made up of around 40% sodium and 60% chloride. It’s commonly used to add flavor to foods or preserve them (). Sodium is a mineral essential for optimal muscle and nerve function. Together with chloride, it also helps your body maintain proper water and mineral balance (, ). Yet, despite its essential functions, ingesting too much salt can have unpleasant effects, both in the short and long term. This article discusses what happens in your body if you eat too much salt in a single meal or day and compares this to the long-term effects of a salt-rich diet.
Short-term effects of eating too much salt Eating too much salt at once, either in a single meal or over a day, can have a few short-term consequences. First, you may notice that you feel more bloated or puffy than usual. This happens because your kidneys wish to maintain a specific sodium-to-water ratio in your body. To do so, they hold on to extra water to compensate for the extra sodium you ate. This increased water retention may result in swelling, especially in the hands and feet, and can cause you to weigh more than usual (). A salt-rich meal can also cause a larger blood volume to flow through your blood vessels and arteries. This may result in a temporary rise in blood pressure (). That said, not everyone may experience these effects. For instance, research suggests that people who are salt resistant may not experience a rise in blood pressure after salt-rich meals (, ). A person’s sensitivity to salt is thought to be influenced by factors like genetics and hormones. Aging and obesity may also amplify the blood pressure-raising effects of high salt diets (, ). These variables may explain why salt-rich diets don’t automatically result in a rise in blood pressure for everyone. Eating a salty meal can also cause you to have a dry mouth or feel very thirsty. Encouraging you to drink is another way in which your body tries to correct the sodium-to-water ratio (). The resulting increase in fluid intake can cause you to urinate more than usual. On the other hand, failing to consume fluids after eating high amounts of salt may cause your body’s sodium levels to rise above a safe level, resulting in a condition known as hypernatremia (). Hypernatremia can cause water to leach out of your cells and into your blood, in an attempt to dilute the excess sodium. If left untreated, this fluid shift can result in confusion, seizures, coma, and even death (, ). Other symptoms of hypernatremia include restlessness, breathing and sleeping difficulties, and decreased urination (, ). SUMMARY Short-term consumption of high amounts of salt can cause water retention, a temporary rise in blood pressure, excess thirst, and, in severe cases, hypernatremia. However, some people may experience little side effects.
Long-term effects of eating too much salt Eating too much salt over a long period of time may bring on several health issues. Research suggests that salt-rich diets significantly increase blood pressure and that lowering the salt content of a person’s diet can help lower their blood pressure levels (). For instance, two large reviews report that a reduction in salt intake of 4.4 grams per day may lower systolic and diastolic blood pressure (the top and bottom numbers of a reading) by up to 4.18 mm Hg and 2.06 mm Hg respectively (, ). However, the observed reductions were close to two times larger in individuals with high blood pressure, compared with those with blood pressure in the normal range (, ). Moreover, these effects are thought to be significantly stronger in salt-sensitive individuals than in those who are not salt-sensitive. Obesity and aging are also though to amplify the blood pressure-raising effects of salt-rich diets (). Several studies link a high salt diet to a higher risk of stomach cancer (, , ). A review including more than 268,000 participants suggests that those with median salt intakes of 3 grams per day may have up to a 68% higher risk of stomach cancer than those with median salt intakes of 1 gram per day (). Another study further suggests that people with high salt intakes may have a two times higher risk of stomach cancer than those with lower intakes. Still, this study doesn’t clearly define what is considered high or low salt intake (). The mechanism behind salt’s effect on stomach cancer isn’t fully understood. However, experts believe that salt-rich diets may make a person more vulnerable to stomach cancer by causing ulcers or inflammation of the stomach lining (). Effect on risks of heart disease and premature death The link between salt-rich diets, heart disease, and premature death is still somewhat controversial. Some studies suggest that high salt intakes cause a rise in blood pressure and a stiffening of blood vessels and arteries. In turn, these changes may result in a higher risk of heart disease and premature death (, , , , ). For instance, one 20-year study notes that participants who consumed less than 5.8 grams of salt per day had the lowest mortality rates, while those who consumed more than 15 grams of salt per day had the highest (). However, others suggest that high salt diets have no effects on heart health or longevity and that low salt diets may actually increase the risk of heart disease and death (, , , , ). These differing study results may be explained by differences in study design, methods used to estimate sodium intake, and participant factors, such as weight, salt sensitivity, and the other health issues participants may be facing (, ). While it’s possible that eating too much salt doesn’t increase the risk of heart disease or premature death for everyone, more studies are needed before strong conclusions can be made. SUMMARY Eating too much salt in the long term may raise your blood pressure and increase your risk of stomach cancer. It may also increase the risk of heart disease and premature death, although more research is needed to confirm this.
Is it possible to overdose on salt? Fatal salt overdoses are rare, as they require people to consume amounts of salt nearing 0.2–0.5 grams per pound (0.5–1 gram per kg) of body weight. This would amount to 35–70 grams of salt (2–4 tablespoons) for a person weighing 154 pounds (70 kg) (). People with health conditions like heart failure, as well as liver or kidney disease, may experience fatal effects if they routinely consume more than 10 grams of sodium per day. That’s equivalent to around 25 grams of salt (). Research suggests that the average individual currently consumes around 9–12 grams of salt per day, with processed foods being the highest contributor (, ). In comparison, health authorities generally recommend people limit their sodium intake to 1,500–2,300 mg per day. This is equivalent to 3.8–5.8 grams of salt each day, or 2/3–1 teaspoon (, , 28). SUMMARY Salt overdoses are extremely rare, as they require the consumption of very large amounts of salt. Most people’s average salt intake far exceeds health authorities’ current recommendations.
What to do if you’ve eaten too much salt There are a few ways in which you can help your body compensate for a high salt meal. First, make sure you drink sufficient amounts of water to help your body regain its desired sodium-to-water ratio (, ). You can also try eating foods that are rich in potassium, such as fruits, vegetables, legumes, nuts, seeds, and dairy. Together with sodium, potassium is a nutrient that plays a key role in maintaining your body’s fluid balance (, 29). Diets rich in potassium may help counter some of the ill effects of sodium-rich diets. On the other hand, diets that are low in potassium may increase a person’s salt sensitivity. Still, more research is needed to confirm this (, 29). Finally, you may try to reduce the amount of salt you consume in other meals. Keep in mind that 78–80% of the salt you eat comes from processed foods or restaurant meals (, ). Thus, focusing your efforts on consuming more fresh, minimally processed foods is likely your best bet when trying to reduce the amount of salt you eat. SUMMARY You may somewhat compensate for a salt-rich meal by drinking sufficient amounts of water, eating potassium-rich foods, and reducing the amount of salt you consume at other meals.
Eating too much salt can have a range of effects. In the short term, it may cause bloating, severe thirst, and a temporary rise in blood pressure. In severe cases, it may also lead to hypernatremia, which, if left untreated, can be fatal. In the long term, high salt diets may cause a rise in blood pressure and increase the risk of stomach cancer, heart disease, and premature death. However, more research is needed to determine if these effects apply equally to everyone. Some people may be affected by high salt intake more severely than others. To compensate for a high salt meal, try drinking more water, eating potassium-rich foods, and reducing your salt intake at other meals.