Study Suggests Eating Too Much Salt May Affect Immune Cell Function

According to a new study, having too much sodium in the blood can cause the immune cells in the body to produce less energy. The effect may cause the immune cells to not work as well as they should, which is a major concern in the midst of a pandemic.

“We've long associated too much sodium in the diet with elevated blood pressure and potential increased risk of cardiovascular disease,” Sarah Anzlovar, MS, RDN, LDN, owner of Sarah Gold Nutrition, tells Verywell. “This new study brings up a possible new effect at the cellular level.”

Health Effects of Too Much Salt

Most Americans eat almost 50% more salt than what is typically recommended to support an overall healthy lifestyle.

While having some salt in your diet helps balance fluids in the body and helps keep your heart and nerves functioning, consuming too much sodium has been linked to high blood pressure and may even raise your risk of premature death.

Research has shown that consuming excess salt can cause blood serum sodium levels to get too high. As a result, sodium can accumulate in places it shouldn't—like sites of inflammation in the body. Because immune cells play a role in the body's inflammatory response, this can ultimately can affect how well those immune cells function.

Along with the tried-and-true strategies to support the immune system—like including enough vitamin C in your diets, getting adequate rest, and staying hydrated—making sure that you are not consuming too much salt can help keep your body in fighting shape.

Salt Disrupts Flow of Oxygen to Cells

The authors of the new study, which was published in the journal Circulation, highlight that past data has shown higher sodium concentrations in the blood affect both the activation and the function of cells that play a role in immune system function. Using this knowledge as a base for further exploration, the researchers set out to find out the "how" and "why" of the effect.

The researchers were able to show that immune cells are negatively affected by too much sodium, specifically by experiencing challenges with the way they produce energy.

The study found that salt can inhibit an enzyme that plays an important role in the respiratory chain, causing the cells to utilize less oxygen. This, in turn, can negatively affect the health of the cell. It's important to note that the researchers only evaluated cells that play a role in immune health for their research, and didn't test actual humans.

Clinical Trials on Salt Intake

The researchers also analyzed the results of two clinical trials. The first study evaluated the effects of eating pizza (a high sodium food) on certain cells found in the blood that play a role in immune health. The second evaluated the effects of taking a salt tablet in conjunction with eating a typical diet.

The results of the analysis indicated that the negative effects of salt intake can occur after a single high-salt meal, but that the effects were not long-lasting.

How To Reduce Your Sodium Intake

The Dietary Guidelines for Americans recommends that most people consume a maximum of 2,300 milligrams of sodium a day—about 1 teaspoon of salt. Some people need to limit their sodium intake even more, depending on their health.

Most people far exceed the recommended limits on salt intake by consuming processed, prepackaged foods, fast foods, and preserved foods.

Salt is a popular flavoring that many people enjoy, but there are other ways to achieve a satisfying taste without the detrimental health effects of excess sodium.

“Interestingly, the biggest contributor to excess sodium in the American diet isn't the salt shaker at the dinner table—it's restaurant foods and processed foods,” says Anzlovar.

To combat the extra dietary salt, Anzlovar says people should "focus on eating mostly whole foods, including lots of fruits and vegetables, which contain potassium and can help balance out sodium intake, and limit packaged and processed foods when managing sodium levels in the diet." 

Try MSG

While it's gotten a bad rap in the past, monosodium glutamate (MSG) is a safe seasoning option that offers a similar flavor if you're trying to reduce your sodium intake.

“MSG has 2/3 less sodium than table salt, and when used in the place of some salt, it can reduce sodium in a dish by as much as 40% without sacrificing taste," Tia M. Rains, PhD, Vice President of Customer Engagement and Strategic Development at Ajinomoto Health & Nutrition, tells Verywell. "The National Academies of Sciences, Engineering, and Medicine has even acknowledged the use of MSG as a strategy to reduce sodium in the food supply."

Easy Diet Swaps to Reduce Sodium Intake

Here are some other tips for lowering your salt intake:

• When dining at a restaurant, ask for sauces and dressings on the side and only add what you need, as these condiments are often teeming with salt.
• When cooking at home, lean on lower-sodium or sodium-free flavorings like garlic and fresh herbs instead of reaching for the salt shaker.
• Avoid salty lunch meat and other processed meats like bacon and sausage. Instead, enjoy fresh slices of turkey or beef.
• Rinse canned beans with water before enjoying them.
• Choose homemade soups instead of canned versions.

More studies are needed to confirm whether excessive sodium intake can, in fact, negatively affect the immune system. However, experts do agree that limiting your sodium intake can support heart, vision, and other aspects of your overall health.