Sodium - Fact Sheet

In this Article (Index)

Learning more about our health, and how to improve it.

• What is Sodium?
• Biological roles of sodium
• Sodium and Food
• Recommended Intakes of Sodium
• Sodium and Table Salt
• Health Risks Caused by High Sodium Intake
• High Blood Pressure and Cardiovascular Disease
• Other Health Conditions and Sodium
• Daily Salt Intake: statistics
• Potassium salt substitute reduces heart disease and death
• Top Sources of Dietary Sodium among Americans
• Sodium isn't only found in table salt
• Tips for Lowering the Sodium in your Diet
• Sodium content in Natural and Processed Foods

What is Sodium?

Sodium. A. Whittall

Sodium is a chemical element with an atomic number of 11. It is a soft and highly reactive metal that quickly forms compounds with other elements. Roughly 2.7% of the mass of the Earth's crust is sodium, making it the sixth most abundant element.

Sodium was discovered in 1807 by Humphry Davy, who called it sodium. German chemist Ludwig Gilbert proposed naming it Natronium, and this name comes from the Latin word "Natrium" which designated a sodium carbonate salt used by Egyptians for mummification.
The Latin word has survived in sodium's chemical symbol Na, first published by Jöns Berzelius in 1814.

Sodium was formed inside the stars, by fusion reactions, and is the 15^th most abundant element in the universe, comprising 0.002% of its atoms.

Biological Roles of Sodium

Sodium is essential for all plants and animals. It is the main positively charged ion (cation) in the extracellular fluid (ECF), and complex biochemical processes keep its concentration there roughly 10 times higher than inside the cells. The flow of sodium cations in nerve cells allows the transmission of nerve signals.

It helps regulate blood pressure, its acid balance (pH), the concentrations of electrolytes in cells, body tissues, and ECF.

Sodium and food

Dietary sodium helps maintain the body working correctly, and a minimum daily intake of around 500 mg is necessary for the body to function properly.

Natural sources of sodium are found in fresh vegetables, fish, and meat. They are more than enough to cover our body's needs, they are mainly in the form of sodium chloride (NaCl), common table salt. However, we consume much higher quantities than necessary, due to the salt added during cooking and preparation of processed foods at industrial food-processing plants, and restaurants.

Table salt has been used for thousands of years as a preservative to protect food from bacteria and fungi and as a flavoring additive. Nowadays, not only sodium chloride, but many other sodium salts are used to provide texture, umami flavor, emulsify, preserve, and thicken processed foods.

Recommended Intakes of Sodium

The National Academies of Sciences, Engineering, and Medicine reviewed the scientific evidence and decided that there isn't enough data to establish a Recommended Dietary Allowance, instead, it defined Adequate Intake (AI) levels, which for adults is 1,500 mg/day, value adopted by the American Heart Association.
The latest edition of the Dietary Guidelines for Americans (2020-2025) or DGA(8) defines a tolerable upper intake level for sodium at 2,300 mg per day for healthy adults.

Sodium and Table Salt

Sodium salts are very soluble in water which leaches them from the rocks and washes them into the oceans. Over billions of years, sodium has accumulated in the world's oceans together with chlorine. Both pair to form sodium chlorine (table salt).

Due to the atomic weights of each element, sodium (22.989) and chlorine (35,453), one molecule of NaCl has a molecular weight of 58.442. This means that for every 1 g of table salt, there are 0.393 g of sodium.

The 2,300 mg (or 2.3 g) per day of sodium limit is equivalent to approximately 5,85 g of table salt which is roughly one teaspoon of salt.

Health Risks Caused by High Sodium Intake

High Blood Pressure and Cardiovascular Disease

Cardiovascular disease promoted by high blood pressure (hypertension) is one of the major global causes of illness and disease, (1) and a high sodium intake is one of the leading risk factors.

A scientific review (2) of different salt-reduction studies reported that a lower salt intake is linked to a lower risk of cardiovascular disease: A reduction of 4.4 g of daily salt intake, equivalent to 1,760 mg of sodium reduces blood pressure by 5.4-2.8 mm Hg in hypertensive subjects, and 2.4-1.0 mm Hg in normal subjects.

Other Health Conditions and Sodium

A high sodium intake is linked to other conditions such as asthma (a), kidney stones (b), osteoporosis (3), and gastric cancer (3).

Daily Salt Intake: statistics

We consume far too much salt!

The average American consumes about 3,400 mg of sodium per day according to the Food and Drug Administration. This is 2.26 times higher than the adequate intake level, and almost 1 ½ times higher than the maximum level accepted under the Dietary Guidelines for Americans.

A study (3) investigated salt added during cooking, or at the table ("discretionary salt intake"), and found that on a global level, they vary from 5.2 to 15.5 g/day.

The share of discretionary salt in the daily intake is highest in less developed countries, with more than 50% of the daily salt intake in Brazil, China, Costa Rica, Guatemala, India, Japan, Mozambique, and Romania coming from seasoning cooking or at the table.
Then come countries like Jordan, Portugal, South Korea, Taiwan, and Turkey with 25-50% of their daily intake supplied by discretionary salt. Finally, developed countries that consume far more processed foods (which contain high amounts of salt), obtain less than 25% of the daily salt intake from home-cooked or table-seasoned foods: Australia, Austria, Canada, Denmark, Finland, New Zealand, the United Kingdom, and the United States of America.

They estimate that for every $10,000 in GDP per capita, the daily discretionary salt intake falls by roughly 8.7%.

Dietary sources of salt vary from one country to another, baked products and bread contribute 25%-40% of daily salt in Europe and the US. Soy sauce and dressings account for 44% of salt intake in Japan. Dairy products make up 15% of the daily intake of salt in New Zealand and Argentina, while grains and cereals add up to 24% of the intake in China and Brazil. Meat provides 31% of the US intake and 4%-16% in Australia, New Zealand, and some South American and European countries.

Sodium, in the form of sodium salt additives or table salt in processed foods, accounts for the excess intake of sodium in most developed and Western countries where 75% of sodium intake comes from sodium added to processed foods. (7)

Government Actions to Lower Sodium in Processed Foods

Some countries have introduced voluntary sodium reduction programs for processed foods, with relative success.

Canada did so in 2012, setting a target of 2,300 mg per day. The 2018 evaluation reported modest reductions and many didn't meet their target: only an 8% decrease in sodium intake between 2010 and 2018. The average Canadian consumed 2,760 mg of sodium daily, higher than the goal, but lower than American sodium intake levels.

In the United Kingdom, the average intake is 3,240 mg of sodium per day, a 15% reduction over the last 10 years, this is mainly due to the reformulation of processed foods through a voluntary program that began in 2006. It has been successful; many foods now contain 20%-40% less sodium than they did one decade ago. The restaurant and catering sectors were added later and are lagging behind the rest of the food industry.

Potassium salt substitute reduces heart disease and death

A Large 2021 study, the Salt Substitute and Stroke Study (5) randomly assigned patients who had a history of stroke or were 60 years of age or older into two groups. One group with 10,504 participants consumed a salt substitute (75% regular salt and 25% potassium chloride) and the other group with 10,491 subjects consumed regular salt. This entails a 25% reduction in salt intake for the group using salt substitute.

It found that the rates of stroke, major cardiovascular events, and death from any cause, were lower for the salt substitute group than for regular salt.

It reported that "Among patients with prior stroke or hypertension, a salt substitute was effective at preventing first or recurrent stroke. Salt substitute was also associated with a reduction in major adverse cardiovascular events and deaths."

The use of Potassium to Lower Blood Pressure is well known; this study also showed that the use of potassium in the salt substitute did not provoke "an increase in serious adverse events due to hyperkalemia," or high levels of potassium in the blood.

The team published a second study (4) that reconfirmed that potassium as a salt substitute isn't likely to provoke hyperalkemia or cardiac arrhythmia,, and that the only restrictions would be advanced kidney disease or the use of potassium supplements or certain diuretics.

They reported that: "Switching from regular salt to potassium-enriched salt substitute appears more likely to provide protection than cause harm for a range of cardiac events, that include acute coronary syndrome, cardiac arrythmia, heart failure, and sudden death."

Top Sources of Dietary Sodium among Americans

As mentioned, among developed nations, the major contributor to sodium in food comes from processed, prepackaged foods.

A study (6) analyzed data from the 2017-2018 National Health and Nutrition Examination Survey and listed the top 15 food categories that contribute 50.83% of the total dietary intake of sodium in America:

1. Pizza (5.3%)
2. Breads, rolls and buns (4.7%)
3. Cold cuts and cured meats (4.6%)
4. Soups (4.4%)
5. burritos and tacos (4.3%)
6. Savory snacks (4.1%)
7. Poultry (4.0%)
8. cheese (3.1%)
9. Pasta mixed dishes (2.9%)
10. Burgers (2.5%)
11. Meat mixed dishes (2.5%)
12. Cookies, brownies, and cakes (2.4%)
13. Bacon, frankfurters, sausages (2.4%)
14. Vegetables (2.2%)
15. Chicken nuggets (1.5%)

Sodium isn't only found in table salt

When we think about dietary sodium we normally think about regular table salt or sodium chloride (NaCl), used to provide taste to dishes that are cooked at home.

Table salt is also used in large amounts in processed foods due to its preservative properties.

However we also consume other sodium salts, which are used as additives in processed foods and some restaurant preparations, below is a short summary of these salts.

Sodium is used for curing meat, baking, thickening, emulsifying, retaining moisture, enhancing flavor, and as a preservative.

Other Sodium Salts

Monosodium Glutamate

Also known as MSG, monosodium glutamate is found in oriental sauces and ready-to-eat noodles and soups. It provides the "umami" taste due to the presence of the glutamate derived from glutamic acid, the compound that generates the umami flavor. The average daily intake of sodium from MSG is around 54 mg. (d)

Sodium Bicarbonate

Baking soda is used in bakery and pastry as a leavening agent. Cookies, muffins, and scones can contain between 350 and 580 mg of sodium per 100 g of baked product. (e). This has led bakery manufacturing companies and baking powder producers to reformulate their products using potassium-based ingredients.

Sodium Metabisulfite

It acts as an antioxidant and preservative for foods. It is also used in the production of cookies and biscuits because it reduces dough shrinkage during baking by making gluten less elastic and more extensible.

Sodium Nitrite and Nitrate

Are meat preservatives used in processed meats. They are used at relatively low levels in foods, a sampling found that levels of nitrate averaged 100 ppm (parts per million) and nitrates 12 ppm or lower. (f)

Sodium Benzoate

Found in many foods, sodas, beverages, and condiments. It is an anti-fungal and anti-bacterial preservative. Maximum dosage, however, is low, 0.1% by weight.

Sodium Tripolyphosphate

Also knwon as STPP, it is used as a preservative in seafood, canned meats, and canned beans, it is a tenderizer, thickener, emulsifier, softener, and retains water, keeping food moist. It reacts with the meat protein (globulin), "enhancing" it. It appears as E451 on European food labels.

Emulsifying Salts

STPP can be also found in processed cheeses that use sodium-based emulsifying salts to help them melt better when used. Its maximum limit is 0.05%.

Other sodium salts used to emulsify are trisodium citrate, tetrasodium pyrophosphate, sodium hexametaphosphate, and disodium orthophosphate.

Artificial Sweeteners

Acesulfame potassium (Acesulfame-K) can also include a sodium salt (sodium ferulate) to eliminate its aftertaste, Cyclamate (sodium salt of cyclamic acid) contains salt, and though it is banned in the US it is still used in Canada, the EU, and the rest of the world. Saccharin (benzoic sulfimide, sodium salt) also called saccharine, benzosulfimide, or E954 (EU food additive) also contains sodium.

Tips for Lowering the Sodium in your Diet

Sodium isn't only used in savory dishes (like soy sauce or bacon), you will also find it in sweet foods that don't taste salty like breakfast cereals and cookies. They contain sodium but not salt. So don't trust your taste buds to detect sodium. Food and Drug Administration

Sodium in food adds up, eating food like bread several times a day adds up over the course of a day (100 g of bread equivalent to 3 slices, adds up to 25% of your daily sodium intake).

The FDA provides tips on how to lower your dietary sodium intake to keep it within the recommended daily value (below 2,300 mg per day).

Read the Nutrition Facts Label

The nutrition facts labe indicates the sodium content in the food in mg and its percentage of the recommended daily value. Compare labels for similar products, andchoose the one with the least sodium. Try to stay below the 100% DV level.

Lower your processed food intake

Roughly 3/4 of your dietary sodium intake comes from processed foods (canned, frozen, baked, restaurant-cooked). Avoid "instant" products like noodles, oatmeal, flavored rice, ready-made pasta, packaged mixes, bottled salad dressings, and sauces.

Choose low-sodium options when eating out

Ask for your dish to be prepared without added table salt. Have your salad dressings and sauces served separately, on the side, so you can use what you really need, avoiding unnecessary sodium. Many restaurants include nutrition information -including sodium- on their menus. Select low-sodium dishes.
On average, a fast food restaurant meal contains around 2,100 mg of sodium for every 1,000 calories.

Salt substitutes

Replace part of your table salt when cooking or at the table, try low- or no-salt seasoners and use herbs or spices to add flavor without sodium.

Use Fresh or Frozen Veggies

Fresh vegetables are very low in sodium, and frozen vegetables without sauce or seasoning are identical to fresh ones. However, canned vegetables and legumes contain sodium. Some of this added sodium can be removed by rinsing with water. Try rinsing canned ingredients before using them.

Fresh Meat, Poultry, and Seafood

As with vegetables, canned and processed meats, fish, seafood, and poultry contain added salt. Buy fresh or frozen unprocessed animal-based food.

Cold cuts, bacon, hot dogs, ham, salami, and pastrami are all high in sodium and other additives, so reduce your intake.

Snack with healthy foods

Snack quality and timing affect your health, and most snacks have large amounts of fats, added sugars, and sodium. Try healthy, low-salt options (nuts, peanuts, chips, pretzels), or consume unsalted versions (pistachio, brazil nuts, seeds, unsweetened raisins) or carrots, celery, and cucumber sticks.

Use unsalted dressings

Healthy oil (olive, or canola) with vinegar or lemon juice are dressings used by the Mediterranean Diet and unlike typical American bottled dressings (Ranch, Caesar, 1000 Islands, etc.) which contain 260 mg to 330 mg per 2 tablespoons (30 g), oil and vinegar/lemon have zero sodium.

Prepacked seasonings can contain around 80 mg of sodium per gram of product. Use low-sodium or sodium-free options, or use less quantity.

Smaller servings

Eat less when eating out, it will reduce your sodium intake. Split a dish with another diner, and eat smaller servings. You can do the same at home. Eating 20% less will reduce sodium intake by 20%. Try the Japanese philosophy of "Hara Hachi Bu," or eat till you are 80% full. Take the leftover portion home, and eat it later.

Sodium content in Natural and Processed Foods

Sodium is found in all natural foods, animals and plants need sodium for their biochemical processes, so it is found in animal and plant-based foods. However, as you will see below, natural foods contain low quantities of sodium. Source: USDA

Sodium content in some natural and processed foods

Values in mg per 100g of food.

Perhaps it's time to consider switching from instant oats to regular rolled oats and reducing the intake of processed foods.