Why There's So Much Sodium in Processed Foods

Packaged processed foods are often high in sodium.
Which processed foods are high in sodium? Most of them. B2M Productions/Getty Images

If you've been told to cut back on your sodium intake, it's more than likely you've been instructed to reduce or eliminate a lot of the processed foods you've been eating, even foods that may not seem salty. That's because sodium is frequently used as a preservative and as a flavor enhancer, either as salt or a component of certain food flavorings.

Sodium as a Food Preservative

Using salt as a food additive is nothing new.

In fact, it's been used as a preservative for centuries. In fact, salt was very important in trade and so valuable it was used almost like a currency at times.

So how does salt work?

Salt is made up of sodium and chloride ions that reduce something called the water activity of foods. The water activity is the amount of water that's available for supporting bacteria growth or allowing other chemical reactions to take place.

Salt might also draw water out of any bacteria present, which kills them or, at least, slows them down quite a bit. In addition, salt enhances fermentation, which can be used as another technique for preserving foods.

Salt is an effective preservative on its own, but sometimes additional chemicals are necessary. Some of them work just like plain salt does to change the water activity, but others work by altering the chemical reactions that would typically result in spoiled foods and rancid fats.

In either case, the end result is food that lasts longer.

Sodium-containing preservatives include:

  • disodium ethylenediaminetetraacetic acid
  • sodium acetate
  • sodium ascorbate
  • sodium benzoate
  • sodium diacetate
  • sodium erythorbate
  • sodium lactate
  • sodium nitrate
  • sodium nitrite
  • sodium phosphates
  • sodium propionate
  • sodium sulfite

    You'll find these chemicals in a variety of foods including salad dressings, canned foods, baked goods, cured meats, canned meats, cheese, jams, jellies and fruit fillings. Look at the ingredients listed on the packages.

    Sodium as a Flavor Enhancer

    Salt is a flavor enhancer that you probably use in your cooking or at the table. But that accounts for just a small amount of the average daily intake of sodium -- less than 25 percent. You can use table salt and still stay under the recommended daily sodium intake of 1,500 to 2,400 milligrams as long as you avoid other sodium-containing ingredients.

    Some flavorings that don't contain salt still contain large amounts of sodium. Monosodium glutamate strengthens your perception of the umami flavor found in savory foods like meat and fish. Sodium acetate is another flavor enhancer that is only slightly salty in taste, but it appears to suppress bitter flavors in foods, so it enhances the perception of sweet flavors. Soy sauce is also used as a flavor-enhancing ingredient, and it's extremely high in sodium.

    Watching Your Sodium Intake

    Look for sodium on the Nutrition Facts label. Even 'reduced sodium' foods can still contain more sodium than you expect. Sodium is listed is milligrams per serving, and that may not mean the whole package. If you eat a whole can of chicken soup, you're really eating two or three servings, so make sure you account for all the sodium. 

    Common processed foods that are high in sodium include:

    • baked goods (including bread and buns)
    • processed cheese 
    • lunch meats, bacon, and sausage
    • pasta meals like mac and cheese in a box or spaghetti in a can
    • pizza (frozen or fresh)
    • snack foods such as chips and even some crackers
    • soup (canned, or powdered)
    • sauces and gravies
    • packaged rice and pasta side dishes

    Sources:

    American Heart Association. "Processed Foods: Where Is All That Salt Coming From?"  

    Institute of Medicine Committee on Strategies to Reduce Sodium Intake. "Preservation and Physical Property Roles of Sodium in Foods."  

    Institute of Medicine Committee on Strategies to Reduce Sodium Intake. "Taste and Flavor Roles of Sodium in Foods: A Unique Challenge to Reducing Sodium Intake."  

    Institute of Medicine. "Dietary Reference Intakes: Electrolytes and Water." 

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