Health Information
Sodium is an essential nutrient. Your body needs sodium for normal fluid balance, nerve function, muscle function and other normal processes. At the same time, consuming more sodium than your body needs can affect blood pressure and, through high blood pressure and other pathways, can be associated with health risks.
This page summarizes information from major health and scientific authorities, including the U.S. Food and Drug Administration (FDA), National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), Centers for Disease Control and Prevention (CDC), American Heart Association (AHA), World Health Organization (WHO), and European Food Safety Authority (EFSA).
My Sodium Today provides tracking and information tools. It does not diagnose medical conditions or provide individualized medical advice.
Sodium Is Essential
Sodium is an essential nutrient. The body needs sodium to help maintain fluid and electrolyte balance and to support normal nerve and muscle function. The FDA, CDC, AHA, WHO and EFSA all recognize that the body needs sodium. NIDDK also describes sodium as important for controlling the amount of fluid in the body.
This means that sodium is not something that should simply be eliminated from the diet.
The health concern described by the major authorities is primarily excessive sodium intake, not the presence of sodium itself.
Sodium and Blood Pressure
The clearest and most consistently supported relationship among the major authorities is the relationship between sodium intake and blood pressure. The FDA, NIDDK, CDC, AHA, WHO and EFSA all describe a relationship between higher or excessive sodium intake and increased blood pressure.
Sodium affects the body’s fluid balance. The FDA explains that sodium attracts water, and consuming a high-sodium diet can increase the amount of water in the bloodstream. This can increase blood volume and, in turn, blood pressure.
EFSA’s scientific review found strong evidence of a positive relationship between sodium intake and blood pressure. Its review of randomized controlled trials also found that reducing sodium intake lowered systolic and diastolic blood pressure.
Why does blood pressure matter?
High blood pressure can damage blood vessels and place additional strain on organs. The CDC and FDA identify high blood pressure as an important risk factor for cardiovascular disease and stroke. High blood pressure can also affect the kidneys and other organs.
Sodium, Fluid Retention and Kidney Health
Sodium plays an important role in the body’s fluid balance. Too much sodium can cause the body to retain additional fluid. The NIDDK explains that excess sodium can contribute to fluid retention, which can cause swelling and increase blood pressure. When kidneys are damaged, they may also have difficulty removing extra sodium and fluid from the body.
The relationship can also work in the other direction. Kidney disease can make it harder for the body to remove sodium and extra fluid, which can contribute to further fluid retention and higher blood pressure.
Swelling and edema
Edema is swelling caused by excess fluid in body tissues. NIDDK explains that edema can occur when the kidneys cannot remove extra fluid and salt effectively. It can occur in areas such as the legs, feet and ankles.
For people with edema or congestive heart failure, NIDDK states that a low-sodium diet can help reduce edema and lower blood pressure.
This is a condition-specific recommendation. It does not mean that every instance of swelling is caused by dietary sodium or that everyone with swelling should independently change their sodium intake.
Kidney disease
For people with chronic kidney disease (CKD), sodium management can be an important part of dietary management. NIDDK states that eating less sodium can help lower blood pressure and may slow CKD progression.
People with kidney disease may have sodium recommendations that differ from general recommendations. Their appropriate intake can depend on their individual health circumstances and should be determined with their healthcare professional or dietitian when appropriate.
What Can Happen When Excessive Sodium Intake Is Reduced?
The major authorities provide strong evidence that reducing excessive sodium intake can lower blood pressure.
Blood pressure
The CDC says that limiting sodium can lower blood pressure, particularly in people who have high blood pressure. The AHA says that cutting back by 1,000 mg of sodium per day can improve blood pressure. EFSA’s review of randomized controlled trials found that reducing sodium intake lowered blood pressure. WHO recommends reducing sodium intake specifically because doing so can reduce blood pressure and cardiovascular risk.
Cardiovascular health
High blood pressure increases the risk of cardiovascular disease and stroke. Therefore, reducing excessive sodium intake can contribute to lower cardiovascular risk by helping reduce blood pressure. This is different from saying that lowering sodium reverses heart disease or stroke.
Kidney health
For people with chronic kidney disease, NIDDK says that eating less sodium can help lower blood pressure and may slow CKD progression. The evidence supports effects such as lower blood pressure and potentially slower progression, rather than a general claim of reversing established kidney disease.
Fluid retention
For people with edema or congestive heart failure, NIDDK states that a low-sodium diet can help reduce edema and lower blood pressure. This applies to particular medical circumstances rather than being a general explanation for all swelling.
Other Health Associations
In addition to blood pressure, major health authorities discuss research connecting higher sodium intake with other health conditions. The strength and nature of these relationships are not identical.
The AHA’s current information says that excess sodium or salt may put people at risk for conditions including kidney disease, stroke, heart failure, osteoporosis, kidney stones and stomach cancer, as well as high blood pressure. WHO also discusses evidence concerning outcomes including cardiovascular disease, stomach cancer, obesity, osteoporosis, Ménière’s disease and kidney disease.
These statements describe associations and effects identified by the organizations. They do not mean that sodium has been established as a direct cause of every condition on these lists.
Why the distinction matters
The strongest and most consistent evidence among the authorities concerns:
High blood pressure is itself an established risk factor for cardiovascular and kidney disease. Other sodium-related health associations have varying levels of evidence and may involve additional biological pathways or risk factors.
Water retention and weight
The AHA also explains that excess sodium can cause water retention, which can lead to puffiness, bloating and weight gain. This type of weight gain is associated with retained water. It should not be interpreted as an increase in body fat.
Sodium Intake That Is Too Low
Sodium is essential, so the goal is not to consume as little as possible. The major authorities generally indicate that sodium deficiency from ordinary dietary intake is uncommon or unlikely in healthy people because sodium is widely present in foods.
The AHA also notes that some people can have different sodium needs because of circumstances such as heavy sweating, heat exposure or medical conditions.
Dietary sodium and low blood sodium are different
Low dietary sodium means consuming relatively little sodium in food. Hyponatremia means that the concentration of sodium in the blood is abnormally low. It is a medical condition and is not simply another name for eating a low-sodium diet. The two should not be treated as the same thing.
If you have been told that your blood sodium is low, or that you have a condition affecting sodium or fluid balance, follow the guidance of your healthcare professional rather than using a general dietary tracking reference to determine what is appropriate for you.
Sodium Recommendations
Different health and scientific authorities use different reference values.
| Authority | Sodium reference |
|---|---|
| FDA | Less than 2,300 mg per day for adults |
| CDC | Less than 2,300 mg per day for teens and adults |
| AHA | No more than 2,300 mg per day for adults |
| AHA | 1,500 mg per day as an optimal goal for most adults |
| WHO | Less than 2,000 mg per day for adults |
| EFSA | 2,000 mg per day for the general adult EU population |
| NIDDK | Less than 2,300 mg per day for general prevention; individual limits may differ with kidney disease |
These numbers are not interchangeable. The FDA Daily Value for adults is 2,300 mg of sodium per day, and this is the reference used by My Sodium Today when calculating %DV. People with certain medical conditions may have different recommendations. A healthcare professional or dietitian can provide individualized guidance when necessary.
See Sodium & Blood Pressure and Sodium & Kidney Health for more detail on those specific topics.
The Bottom Line
Sodium is an essential nutrient, but excessive sodium intake can raise blood pressure.
Reducing excessive sodium intake can lower blood pressure. For people with certain conditions, such as chronic kidney disease, edema or congestive heart failure, sodium reduction can have additional documented benefits. At the same time, sodium should not be eliminated, and a general sodium reference should not be assumed to be an individualized medical prescription.
My Sodium Today is designed to help you record, calculate and understand your sodium intake using the FDA Daily Value as its primary tracking reference.
Sources
- U.S. Food and Drug Administration (FDA)
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institutes of Health (NIH)
- Centers for Disease Control and Prevention (CDC)
- American Heart Association (AHA)
- World Health Organization (WHO)
- European Food Safety Authority (EFSA)
See References for the specific sources used.