By Dr. Mercola
Long before probiotic supplements hit the shelves, people have been eating fermented vegetables and meat for their high nutritive and health value. In many areas, fermented foods are also a delicacy, taking on the flavor of the culture, such as Japanese kimchi or German sauerkraut.
Hundreds of years ago, fermentation was used to preserve foods, and later came to be valued for medicinal and nourishing properties.
In the U.S., the art of fermenting foods was largely lost, as many were unaware nearly 85 percent of your immune system resides in your gut and fermented foods improve the diversity of your gut microbiome.
When the bacteria in your gastrointestinal (GI) tract are not properly balanced, it can trigger allergies, autoimmune diseases and even impact your weight.
With increasing media attention on the importance of nutrition for overall health, more people are becoming weary of processed foods and the dubious health claims that go along with them.
While many of the popular fermented foods are vegetables, research has identified enzymes and peptides found in fermented fish were associated with immune stimulating properties and tissue repair.2
What Is Fish Sauce?
In this short video, chef Spike Mendelsohn takes a tour of the Red Boat Fish Sauce factory and discusses how the sauce is made with the owner. Fish sauce is a pungent condiment used commonly in Asian foods.
Some compare the smell of the product to a wet cat.3 Most people agree the odor emanating from the bottle isn't pleasant, but also agree the added depth of flavor to the food is welcome. Well-made fish sauce is produced by fermenting whole fish with salt and water.
The salt effectively kills harmful bacteria in the fish as it ferments.4 No other ingredients are added to a traditionally made, quality product. These three ingredients are placed in barrels and allowed to sit between 12 and 18 months. The shorter the time period, the fishier the taste of the end product.
Although we call it fish sauce, the ancient Greeks used something similar called garos and the ancient Romans called it garum.5 The Malays called it ke-chap and the Chinese called it ke-tsiap.
Whatever it was called, the ancient form of fermentation included using anchovies, sea salt and water in barrels, before the product was pressed and the brown liquid extracted.
Unfortunately, modern processing uses inferior fish (sometimes laden with toxins), a quicker chemical fermentation process and sweeteners. In a traditional form, the product contains fermented by-product of the entire fish, harvested from clean water and rich in extracted minerals and vitamins.
Fish silage is a liquid product made from fish or parts of fish that are liquefied through the action of acids added to the fish and enzymes found in the fish.6 While fish silage and fish meal were part of the study examining enzymes associated with the immune system, these products are used for animal feed, mainly in pig or cattle farming.7
The Difference Between Decomposition and Fermentation
Fish sauce has been referred to as the "mother of all condiments,"8 produced in combination with enzymes commonly found in the fish to result in an autolysis or self-digestion of the flesh. Fermentation reduces the fish to a liquefied product, but it is not the same as decomposition that accompanies bacterial growth after death.
Originally, fermentation was done to prevent decomposition of the food. Samples of garum were found in containers preserved in Pompeii, which were comparable to well-made fish sauce produced in Italy and Southeastern Asia.9
Preservation is accomplished with the use of lactic acid bacteria fermentation that prevents rotting or decomposition of the fish.
During decomposition or putrefaction of animal flesh, biogenic amines are formed — namely putrescine and cadaverine. Both of these are biomarkers that are foul-smelling, toxic compounds, giving rotting meat their characteristic odor and thought to be the scent detected by cadaver dogs.
Cadaverine is a breakdown product of the amino acid lysine, and putrescine is from the amino acid ornithine.10 The production of these two components happens during aerobic bacterial growth which breaks down the tissue.
Autolysis, or the breakdown of tissue from bodily enzymes, is also part of decomposition. Since decomposition begins at the moment of death, it is important for the first steps of the fermentation process to be done immediately after the fish are caught.
From Fish Sauce to Ketchup
The ancient form of fish sauce adds a unique flavor to food when used in cooking or after food has been brought to the table. Manufacture of the product for Western consumers originally included adding sweetener to the product.
However, over time, the process and the product changed completely and became what Americans know today as catsup or ketchup. The changes created a product far removed from the "sacred food" held dear by cultures for nutrient value that renewed the people.
Once believed to help improve fertility, promote good health and speed recovery from illnesses, ketchup now holds little to no nutrient value.
Early British recipes contained anchovies, wine, spices, vinegar and shallots.11 Unfortunately, the industrialized ketchup is laden with high-fructose corn syrup, distilled vinegar and a small amount of tomato paste.12
Most people add more than 1 tablespoon of ketchup to their burgers, which means ketchup may contribute a significant portion of sugar and carbohydrates to your daily diet.
The Importance of Salt to Nutrition and Taste
Salt has been used to preserve and enhance the flavor of foods for thousands of years. Research has now determined fish sauce may reduce your overall sodium intake, while not impairing the flavor of your food.15
Although salt is important to your health and nutrition, many people consume large amounts of unhealthy refined salt in processed foods.
Between 2011 and 2012 the average American consumed nearly 3,500 milligrams (mg) of salt per day, 1,200 mg more per day than recommended by the U.S. Centers for Disease Control and Prevention (CDC),16 and 2,000 mg more than what is recommended by the American Heart Association.17
Much of the salt consumed is refined and has next to nothing in common with natural salt.
The structure of processed salt is radically altered during refining as it is heated above 1,200 degrees F and then chemically "cleaned." These processes alter the natural chemical structure of the compound.
Meanwhile, natural unrefined salt is a necessary component of blood plasma, lymphatic fluid and amniotic fluid. It helps your brain communicate with your muscles and is used to regulate your blood pressure.
Adding fish sauce to your cooking not only may reduce the amount of refined sodium you consume, but may also have a beneficial impact on your blood pressure. Warnings about salt use are grounded in the belief high amounts of sodium may increase your blood pressure, a precursor to heart disease and stroke. It is true that lowering your salt intake may lower your blood pressure, but only between 1 millimeter of mercury (mm Hg) and 5 mm Hg for systolic and diastolic pressure.18
Research has found that consuming fish sauce has a tendency to lower blood pressure in lab animals.19 Researchers isolated angiotensin I-converting enzyme (ACE) inhibiting proteins from fish sauce. These are some of the same proteins used in ACE inhibitor medications to help control high blood pressure. Too little sodium may also be harmful to your health.
Several studies demonstrate problems too little sodium can cause, such as an increased risk of death if you have type 2 diabetes,20 increased insulin resistance21 and an increase in low density lipoproteins (LD) and triglycerides.22 As most people get their salt from processed foods and restricting natural salt has no proven benefits, you may find eating real, organic foods and adding natural Himalayan salt as needed to your foods will meet your needs.
Protein Hydrolysates and Antioxidant Activity Found in Fish Sauce
Researchers found protein hydrolysates were created23 during the fermentation process, which have significant health benefits. They improve the ability of skeletal muscle to absorb free amino acids required to build more muscle, affecting body composition, exercise performance and muscle growth.24
Protein hydrolysates are also used for tissue repair, resulting in more rapid uptake of amino acids, as compared with consuming whole proteins or supplementing with free-form amino acid mixes.25 Additionally, they promote a strong insulinotropic response, meaning they stimulate the production and action of insulin in the body.26
This means protein hydrolysates found in fish sauce may reduce your insulin resistance, thereby lowering your risk for metabolic syndrome and type 2 diabetes. The effects of the protein hydrolysates are present only when you consume the fish sauce. There is no extended effect after the hydrolysates have been metabolized.
During the fermentation process enzymes are also created that help to support your immune system and play a role in scavenging free radicals.27 Oxidative stress and free radical production are strongly linked to aging and diseases such as arthritis, cancers28 and neurodegenerative diseases.29
Free radicals and reactive oxygen species (ROS) are generated in your body from a variety of different metabolic actions, exposure to physical or chemical conditions or during an illness or disease state. In order to reduce the negative effects of free radicals on your body, you need a steady diet of antioxidants. When free radicals overwhelm your ability to control the negative effects, oxidative stress results.
Foods that provide you with those antioxidants are functional foods as they help manage your health and reduce the effect of disease.30 Using a luminol chemiluminescence method, researchers found the antioxidants in fish sauce had strong scavenging capability.31
Using Fish Sauce
Although you may be offended by the odor coming from a bottle of fish sauce, you'll likely find the additional layer of flavor it adds to your food enjoyable. The usefulness of this condiment extends well beyond Asian cooking. Professional chefs sing the praises of this sauce as the secret ingredient in many of their dishes.32
It is important to purchase a quality product that underwent natural fermentation and had no additional chemicals added. Quality fish sauce will last a long time as the salt used in fermentation eliminates bacterial growth responsible for food spoilage. However, if you find it's molded or turns cloudy, it's best to dispose of it. Store it in a cool, dry and dark place that has a stable temperature. Refrigeration may lead to crystallizing of the salt in the product.
Red Boat fish sauce has been used and enjoyed by multiple professional chefs33 on fish, chicken, steak and pork chops. Despite a strong odor and flavor, it has also been successfully used in salad dressing34 and to season collard greens.35 Red Boat fish sauce uses an artisanal method of slow fermentation to achieve its flavor, which consumers assert has a smoother and less fishy flavor than other brands.36
Buyer Beware: Poor Quality Fish Sauce Could Be Hazardous to Your Health
For all its benefits, poor quality fish sauce may do you more harm than good. In October, 2016, Vietnamese Prime Minister Nguyen Xuan Phuc ordered the country’s ministries of health and industry to verify quality of fish sauce products, as news of chemical use in the industry spawned fears.37
A Vietnamese news article claimed more than a dozen chemical additives had been found in a popular fish sauce, including flavor enhancers, coloring agents and preservatives. Tests conducted by a consumer rights group also found high levels of arsenic in 67 percent of the 150 samples of Vietnamese and Thai fish sauce brands.38
Price can be a factor when determining quality. A cheap price may well mean inferior quality and use of unsavory additives. For example, in Vietnam, adulterated products may sell for less than $2 whereas a high quality, traditionally fermented fish sauce typically sells for $9.
Also pay close attention to expiration dates, and be sure to store it in your refrigerator.39 As a general rule, the Association for Science Cooperation in Asia (ASCA) suggests traditionally fermented fish sauce has a shelf life of five years. That said, it’s important to remember that while the fermentation process very effectively kills of bacteria — to the point that no pasteurization is required — there’s no guarantee that each and every bottle of fish sauce will always be good.
It can go bad at any time before or after its opening, as chemical reactions can deteriorate the quality over time. Always inspect the product for color, mold and “off” flavors or odors, and discard if it looks, smells or tastes odd in any way.