Salty soy sauce a double-edged sword

By Jasminee Sahoye

Kikkoman Soy Sauce
Kikkoman Soy Sauce

A condiment in Asian cuisine also used by many in the Caribbean, soy sauce – known as tamari – has a range of nutritional benefits.

But researchers have found that one teaspoon serving of this dark, savory sauce has 335 milligrams of sodium, according to the USDA National Nutrient Database.

While sodium is an essential mineral required for basic bodily functions, including nerve transmission and regulating your blood pressure, the recommended upper limit of sodium for adults is 2,300 milligrams per day. It drops to 1,500 milligrams a day for those who have a history of cardiovascular disease, are African American or who are 51 or older.

A 2009 publication of the Journal of Food Science found that substituting naturally brewed soy sauce for table salt in foods did not lower the taste intensity of the food, despite the fact that the total sodium content was reduced. In some cases, there was 50% less sodium in the foods and no discernible change in taste.

A 2005 review in the Journal of Bioscience and Bioengineering found that soy sauce had anti-allergenic properties. In a cell-line study, shoyu polysaccharides produced during the fermentation process required to make soy sauce, demonstrated potent anti-allergic abilities.

In a study, participants who ingested soy sauce and had allergies exhibited more improvement than those taking the placebo. Scientists concluded soy sauce held great promise in treating allergies, although further study was needed.

The same review found that the condiment was very high in shoyuflavones, a natural antioxidant, that protects your body from damage from free radicals, which your body makes naturally as it digests food. Free radicals can speed up the aging process, as well as potentially increasing your risk of developing heart disease or cancer.

The author of the review concluded that the antioxidants in soy sauce helped reduce the effects of inflammation, as well as improved overall gastric acid production, thus helping with digestion. Additionally, the antimicrobial properties of soy sauce were found to be effective in protecting the body from certain bacteria.

Kayla T. Daniels, Phd, known as the Naughty Nutritionist and author of The Whole Soy Story: The Dark Side of America’s Favourite Health Food, says while soy sauce made in the old-fashioned way – about 22 days to be fermented – is a healthy and nourishing product. But she says the most common soy sauces sold in supermarkets and served at the majority of restaurants are made in two days or less.

Soybean meal and often corn starches are rapidly reduced to their component amino acids using a high-tech process known as “rapid hydrolysis” or “acid hydrolysis,” which involves heating defatted soy proteins with 18% hydrochloric acid for eight to 12 hours, then neutralizing the brew with sodium carbonate. The result is a dark brown liquid – a chemical soy sauce.

She says of commercial soy sauce, “when mixed with some genuine fermented soy sauce to improve its flavor and odor, it is called a ‘semi-chemical’ soy sauce.” Sugars, caramel colorings and other flavorings are added before further refinement, pasteurization and bottling.

Daniels says undesirables that appear during chemical hydrolysis are levulinic and formic acids, instead of beneficial lactic acid, and the gas produces dimethyl sulfide,hydrogen sulfide and furfurol from the amino acid methionine. The hydrolysis process also results in total destruction of the beneficial and essential amino acid tryptophan.

In a surprising discovery, researchers from the University of Missouri School of Medicine have found that soy sauce contains a potent antiviral compound that may someday be used against the HIV virus, though the drug has yet to be tested in humans.