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Eating foods high in sodium has traditionally been thought to be harmful to health, especially cardiovascular health. Because of this caution, which has circulated for some time, most modern grocery stores carry foods labeled “low-sodium” or “sodium-free” to attract health-conscious buyers. But it’s less common to see labels listing the optimal sodium-to-potassium ratio. However, this is often more of an important influence on health than sodium on its own.
Although a high-sodium diet can be problematic for health, it does not mean sodium is unhealthy. As with many essential minerals, the body requires it in specific amounts. Sodium’s counterpart is potassium, and the two have a very important partnership that requires balance. These two essential minerals are required for human health and have a yin-yang relationship.
Sodium 101
Sodium is considered an essential mineral in the body and is required for normal physiological function. While “sodium” and “salt” are often used interchangeably, it’s important to understand the difference. Salt, or table salt, is an ionic compound between sodium and chloride (NaCl). Considering this, 5 g of salt is the equivalent of 2.3 g of sodium. Unlike salt, sodium occurs naturally in meat, seafood, and dairy.
Most people do not have to worry about sodium deficiencies; the main health concerns come from excess due to the overconsumption of ultra-processed foods. The trends from a 1999 – 2016 NHANES study found that less than 23% of Americans adhered to dietary sodium guidelines. A newer study of low-income Americans determined that the average daily sodium intake is 4.5 g and 4.0 g for African-American and European Americans, respectively, which exceeds the national average estimate of 3.4 g per day. While older research suggested a maximum of 2.3 g of sodium per day for adults, newer research now suggests 3-5 g of sodium as the optimal range for health.
For years, public health guidelines have promoted the reduction of dietary sodium due to the association between high-sodium diets and hypertension, stroke, and other cardiovascular problems. There is some evidence that consuming more table salt (i.e., sodium chloride (NaCl)) versus sodium (i.e., unrefined sea salt) is associated with health risks. Recommendations to decrease salt in the diet result from overconsumption and the overuse of salt as a flavor enhancer and preservative in processed foods. According to one study looking at data from NHANES 2007 – 2010, two categories of food, “grain products” and “meat, poultry, fish, and mixtures,” provided 2/3 of the total sodium intake. The addition of two more categories, “milk and milk products” and “vegetables,” increases that number to 4/5 of the sodium sources.
But what does sodium do in the body, and why is it necessary? Sodium plays a key role in cellular homeostasis and fluid balance in the body. However, for this to happen, the body needs less than 500 mg daily. It is also the major extracellular ion and is involved in an important pump that regulates the movement of molecules in and out of the cell for essential body processes, including free calcium concentration, membrane potential, and cell volume.
Although rare, it is possible to have a sodium deficiency. When the levels of sodium in the blood are low, it’s known as hyponatremia. Symptoms include:
Symptoms generally occur when there is excessive sodium loss or excessive fluid compared to sodium when excess water is consumed without sodium and other electrolytes after excessive sweating, such as during intense exercise. They can also occur after severe instances of diarrhea or vomiting.
Potassium 101
Potassium is sodium’s counterpart. It is the major intracellular ion and plays a key role in the sodium pump that regulates key body processes. The pump is also called the sodium-potassium pump or the sodium-potassium-activated adenosine triphosphatase (ATP) protein complex. This complex uses ATP energy to move three sodium ions out of the cell and two potassium ions into the cell, allowing nutrients, metabolites, and other ions to have energy to move across the cellular membrane. This also regulates cellular volume.
Additionally, potassium is involved in:
- Blood pressure regulation
- Bone health
- Heart contractions
- Muscle contractions
The adequate potassium intake for healthy adults without impaired potassium excretion is 3.4 g and 2.6 g for men and women, respectively. The number is lower for children and young teenagers and higher for lactating women. However, very few American adults reach this level. Based on data from the 2017 – 2018 NHANES study, the average potassium intake in Americans is 2,496 mg per day. This is lower than the reported average intake of 2,800 mg daily from the 2011 – 2012 NHANES.
Potassium deficiency (i.e., hypokalemia) occurs when blood levels drop below 3.6 mmol/L. The most common causes are chronic diarrhea and excessive use of laxatives or diuretics, although certain illnesses also increase the risk of low potassium levels. Symptoms include:
- Constipation
- Excessive thirst
- Heart palpitations
- Low blood pressure
- Muscle weakness or cramping
- Paralysis
- Vomiting or nausea
Although the word “salt” is most associated with sodium, certain salts contain sodium and potassium. For example, compared to table salt, which contains a relatively low amount of potassium (43.7 +/- 30.7 mg potassium/100 g), French sea salt, bamboo salt, and Himalayan pink sea salt all contain potassium amounts of 284.3 mg (+/- 3.6), 399.4 mg (+/- 7.9), and 246.6 mg (+/- 32.2), respectively.
Foods Rich in Sodium and Potassium
Examples of foods that are naturally rich in sodium, in order from greatest to least, include:
- Artichokes
- Beets
- Spirulina
- Turnips
- Celery
- Leafy greens, especially Swiss chard
- Sweet potatoes
- Celery
- Carrots
The range of sodium in a cup or serving of these raw foods is 50 mg to 120 mg (2-5% daily value recommendations), which is significantly lower than processed foods that generally have thousands of milligrams of sodium per serving.
For most people, the goal is to reduce sodium intake rather than increase it. Many studies demonstrate that 70 to 80% of daily sodium comes from processed foods rather than sodium naturally found in food or added salt during cooking or eating. Processed foods also provide little to no potassium, leading to a very high sodium-to-potassium ratio. While it is challenging to avoid all processed food items in the diet, individuals seeking lower sodium levels due to health concerns should aim to minimize processed, packaged, and canned foods when possible.
Restaurant meals are another source of high-sodium meals. It is common for chefs to add copious amounts of salt when preparing food, especially at restaurants and fast food places that rely on quick and pre-prepared foods. Individuals watching their salt intake should be mindful of this when eating at restaurants. If sodium is unavoidable, individuals might consider adding potassium-rich foods to their out-to-eat meals to improve their sodium-to-potassium ratio.
Potassium is abundant in many plant foods. Although bananas are a commonly recommended high-potassium food, numerous plant-based foods also provide potassium. The following potassium-rich foods, which are listed from greatest to least, all have more potassium per 1 cup or general serving than a medium banana (422 mg):
- Beet greens (1309 mg)
- Adzuki beans (1224 mg)
- California avocado (1166 mg)
- Canned tomato puree (1098 mg)
- Large white beans (1004 mg)
- Green soybeans (970 mg)
- Lima beans (969 mg)
- Swiss chard (961 mg)
- Russet potatoes (952 mg)
- Red potatoes (943 mg)
- Acorn squash (896 mg)
- Spinach (838 mg)
- Passion fruit (821 mg)
Final Thoughts
Sodium and potassium are important micronutrients for human health. However, health issues arise when sodium intake exceeds potassium. Improving the sodium-to-potassium ratio may be a helpful strategy for overall health. Read more about the sodium-potassium relationship here.
Before beginning nutrition and lifestyle practices to improve sodium-to-potassium ratios, talk to a doctor, nutritionist, dietician, or another healthcare team member for personal options based on individual circumstances.
