Soy Sauce: How It's Made and How It Can Affect Your Health

Though having enough salt in your diet is important, eating too much of it can lead to health conditions like high blood pressure. Unfortunately, soy sauce contains salt—but the sauce is also linked to some health benefits. Learn how soy sauce is made, how the condiment can affect your health, and some soy sauce alternatives.

How Soy Sauce Is Made

There are different ways to make soy sauce. Traditionally, it's prepared with soybeans, wheat, salt, and fermenting agents (mold or yeast). The mixture is left to ferment for eight months or more; then, it is pasteurized before it's bottled.

Quicker, cheaper methods of making soy sauce—which may be labeled as hydrolyzed soy protein—are generally more chemical-driven. Manufacturers may use additives to enhance color and flavor. Furthermore, some soy sauce products have been found to contain unwanted compounds, including known carcinogens. According to a 2014 article published in Comprehensive Reviews in Food Science and Food Safety, some of these quicker methods can lead to the production of a chemical called 3-MCPD. This chemical has been tied to tumors, infertility, and kidney damage in animal studies, but there is little evidence about its effects on humans.

Soy sauce, like other fermented foods, also contains significant amounts of histamine. Your body releases this chemical to increase inflammation, which can aggravate conditions like rosacea. Too much histamine can also trigger symptoms such as headaches, dizziness, itching, rashes, and digestive problems. If you're sensitive or allergic to gluten, wheat, or soy, then you may want to avoid soy sauce.

The Salt in Soy Sauce

While traditional soy sauce is low in calories and carbs (with less than 10 calories and 1 gram of carbs per tablespoon), it has very high levels of sodium. A single tablespoon contains over 900 mg. That is more than a third of the recommended daily limit for healthy adults (2300 mg, according to the Department of Agriculture and Department of Health and Human Services).

If your body is sensitive to sodium, a sodium spike may trigger water retention, which can result in bloating or slight swelling around the hands and feet. You might notice indentations in your skin after you remove your socks, or that your rings or watch fit a little snugger. And over time, having too much sodium can increase your risk for heart disease.

The Health Benefits

Despite having a lot of salt, soy sauce could also help protect your health. According to a 2019 Biotechnology Advances review, soy sauce can reduce immune responses, helping people who suffer from seasonal allergies. Other studies also showed that dark soy sauce could be an antioxidant.

Besides soy sauce, other fermented soy products have also been linked to health benefits. For example, a 2019 Nutrients study found that tempeh could be linked to healthier gut microbiomes. Meanwhile, natto may be able to help prevent blood clots and high blood pressure. Overall, a 2019 article published in Food Chemistry found that fermented soy products showed promise in preventing inflammation, diabetes, and cancer. However, more research is needed.

Soy Sauce and Soy Sauce Alternatives

If you enjoy soy sauce and can tolerate it well, make sure to use naturally-brewed varieties, according to nutritionist Cynthia Sass, MPH. She recommended Kikoman's Organic Soy Sauce. However, keep in mind that lite, reduced sodium, or less-sodium sauces can still be high in salt. Most still provide about 600 mg of sodium per tablespoon.

But if you are allergic to soy sauce or want a lower sodium alternative, you can also try coconut aminos. Sass recommended Bragg's Coconut Liquid Aminos, which is made with organic coconut blossom nectar, distilled water, organic apple cider vinegar, and sea salt. It's both gluten- and soy-free. And, though the flavor is less intense than soy sauce, one tablespoon portion provides just 140 mg of sodium (6% of the recommended daily limit).

Coconut aminos can be used as a one-to-one substitute in any recipe, or as a condiment, Sass said. One of the ways she recommended using coconut aminos is in a simple stir-fry sauce. To make the sauce, mix the aminos with some fresh-squeezed tangerine juice, freshly grated ginger root, minced garlic, and crushed red pepper. Then, sauté with a generous portion of veggies. Serve your stir-fry with a lean protein over a small scoop of brown or wild rice, and top with chopped nuts or pumpkin seeds.

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Cynthia Sass, MPH, RD, is Health's contributing nutrition editor, a New York Times best-selling author, and a private practice performance nutritionist who has consulted for five professional sports teams.