So, how do fermented foods exert these health benefits?
Why fermented food is good for health?
The health benefits of fermented foods are usually attributed to the probiotics they contain, but not all fermented foods contain live bacteria. However, even fermented foods containing a small amount of probiotics are healthy. Facts have proved that the health characteristics of fermented food can also be attributed to its fermentation process and bioactive compounds produced by fermentation, and the existence and activity of probiotics are not inevitable.
Some important features of fermented food in promoting health include:
Many lactic acid bacteria found in fermented food can produce bioactive peptides, which are small organic molecules formed by amino acids and connected by peptide bonds. Most of them are produced by bacteria hydrolyzing protein in food. Bioactive peptides have a variety of human metabolism and physiological regulation functions, some of which are called bacteriocins with antibacterial properties, while others have the activity of promoting immunity. In addition, many bioactive peptides also have hormone regulation, blood pressure reduction, antioxidation and neuromodulation.
Phenolic compounds are small molecules characterized by a cyclic chemical group called phenol. We may often hear about phenolic compounds found in many vegetables and fruits. In fact, the fermentation process will also increase the level of some beneficial phenolic compounds, which have antioxidant properties and can help balance the intestinal flora.
Anti-nutritional substances are compounds in plant foods, which can reduce or hinder the absorption of beneficial nutrients in food. Food fermentation can reduce the level of some anti-nutritional substances, such as phytic acid in soybeans and grains, by increasing the activities of some enzymes that decompose these substances.
Fermented food is rich in prebiotics and micronutrients with high bioavailability. Fermentation can improve the bioavailability of a series of nutrients, including vitamin B, iron, zinc and calcium, by decomposing anti-nutritional substances, such as phytic acid. The fermentation process can also synthesize some vitamins that are vital to the body, especially vitamin B and vitamin K. Vitamin B is very important for energy production and nervous system function. Vitamin K is necessary for blood coagulation and an antioxidant.
Fermentation helps to decompose indigestible compounds in food, including lactose in dairy products and fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs) in vegetables, grains and beans.
Most fermented foods are rich in beneficial microorganisms. In addition, due to its chemical structure, most beneficial microorganisms in fermented food can naturally resist the erosion of gastric juice, thus entering the intestine intact. The microbial community in fermented food is very complex, especially in natural fermented food, which means that fermented food can provide us with more beneficial microorganisms than any probiotic supplement. Even if the final appearance and taste of food are the same, subtle differences in the production process, including raw materials, environmental conditions, types of microorganisms used in fermentation, etc., will lead to different beneficial microorganisms.
Since fermented foods have so many health benefits, how can we incorporate them into our daily diet? First of all, we need to know some common fermented foods in the world.
Ordinary fermented food
Almost every culture in the world has its own fermented food. Fermentation not only makes the diet diversified, but also makes the food better preserved and more nutritious, and even helps to remove some harmful substances from the food. The vitality behind fermentation, that is, active beneficial microorganisms, also has a beneficial impact on our health. The types of beneficial microorganisms also contribute to the diversity of fermented foods. Let's take a look at some of the most common fermented foods in the world and their origins and uniqueness.
At the beginning of the 20th century, yogurt was sold as medicine in pharmacies. Soon after, when Isaac carazo from Barcelona began to produce yogurt mixed with jam, the yogurt industry appeared. His son finally founded Danone in France and opened the first Danone yogurt factory in France on 1932. Now yogurt has become a very common drink all over the world, and it is becoming more and more diversified.
Kefir is a fermented dairy product, which originated in the Caucasus mountains. It has slight bubbles and sour taste, and is fermented by Kefir grains, which are living bacterial cultures composed of protein, lipids, sugars, bacteria and yeast. Bacteria and yeast feed on the nutrients in Kefir grains to form a microbial culture. Kefir can be made from milk, goat milk or sheep milk. It contains yeasts such as Kluyveromyces lactis and Saccharomyces cerevisiae, and a variety of lactobacilli including Lactobacillus kefir.
Cheese is a fermented dairy product, which is solidified by casein in milk. In the process of cheese production, microorganisms such as lactic acid bacteria acidify milk, while rennet coagulates milk. Once the solid matter in dairy products is separated, it is usually pressed into a certain shape, and after a ripening process, it promotes the growth of various molds. The source of milk, the types of bacteria and molds, the processing and ripening environment of cheese are intertwined, which affects the aroma, flavor, texture and color of cheese. The cheese made has different habits and uses different bacterial starters, so each cheese has its own unique microbial community.
The origin of cheese is unknown, but before Roman times, there were historical records of making cheese all over Europe. Traditional cheese is made from raw milk after a long period of fermentation, which is very different from the industrialized cheese that most people eat today. Now many processed foods that pretend to be cheese are actually not cheese at all.
Sauerkraut, we are familiar with Northeast Sauerkraut and German Sauerkraut. Chinese cabbage in northeast China is fermented with sauerkraut, while German cabbage is fermented with sauerkraut. There are also some differences in production methods. Kimchi actually originated in northern China in the 4th century BC and may have been introduced to Europe by Mongols. Sauerkraut often contains a large number of Leuconostoc, lactic acid bacteria and pediococcus.
Kimchi refers to all kinds of pickled and fermented vegetables, the most famous of which is Korean kimchi. Pickles usually contain cabbage, carrots, peppers, garlic, onions, ginger and salt, and occasionally other ingredients such as sesame, apples and pears are added. The main bacteria related to pickle fermentation are lactic acid bacteria. Kimchi is also a traditional fermented food in China, such as the famous Sichuan Kimchi, which is also pickled with various vegetables, and the dominant bacteria are lactic acid bacteria.
In Asia, people have been eating fermented bean products for a long time. Fermentation improves the nutritional value of soybean and greatly reduces the content of anti-nutritional components in soybean.
Douchi is a traditional fermented soy sauce in China, which is made from black beans or soybeans through fermentation. Tianbei (Indonesian Douchi) and natto also come from China's Douchi. Tempura is a traditional bean product in Indonesia, which is made of cooked, peeled and fermented soybeans. Usually produced by Rhizopus oligosporus fermentation. Natto is a fermented bean product from Japan, which is famous for its incredibly spicy taste and aroma. It is fermented by Bacillus subtilis and is a traditional breakfast food in Japan. Miso is a kind of salted bean paste, which is fermented by a mold called Aspergillus oryzae. Fermented bean curd is made from soybeans first and then fermented.
Black tea fungus is a kind of fermented tea beverage, which is generally made from black tea or green tea by fermentation of various yeasts, lactic acid bacteria and acetic acid bacteria. Kombucha is thought to have originated in China, Russian or Eastern Europe around 220 BC, and is also called Kombucha, Haibao or Weibao in China.
Pu 'er tea is also a fermented tea, which is produced in Yunnan, China. It is fermented by microorganisms, and the same tea is also used to make green tea and black tea. Traditionally, Pu 'er tea must be aged for more than 15 years, but now people have adopted some technologies to speed up the fermentation process.
Wine is an alcoholic beverage fermented from grapes. Many studies believe that moderate drinking of wine is beneficial to health, but this is not because alcohol itself brings health, but because of bioactive substances, the most famous of which is resveratrol. Therefore, it must be in moderation.
Wine is also not a good source of probiotics because of its high alcohol content, and most microorganisms are not suitable for living in it. But some natural wines may contain some lactic acid bacteria, such as pediococcus pentosaceus. Most commercial wines will filter out all bacteria, including any residual beneficial bacteria, which is often the cause of some annoying additives in wine, such as sulfur dioxide.
Beer is also a fermented beverage. First, soak the grain in water and add yeast for fermentation. Before the grain is fermented into beer, it must germinate, and the complex carbohydrates in the grain must be decomposed into monosaccharides by releasing enzymes. Monosaccharide provides nutrition for yeast and then produces alcohol. Most beer is fermented by Saccharomyces cerevisiae. Beer is the most widely consumed fermented beverage in the world. However, it is worth noting that beer, like wine, contains alcohol, and its beneficial effects are related to the bioactive substances in it, but have nothing to do with alcohol, so it is not suitable for drinking in large quantities.
Chocolate is also fermented food, do you know? Chocolate is fermented from the seeds of cocoa trees in the Amazon rainforest. After harvesting cocoa pods, seeds and pulp can ferment by themselves. Microorganisms that ferment cocoa include Lactobacillus fermentum, Acetobacter pasteurensis and four kinds of yeasts.
Fermented cocoa beans will kill many microorganisms after drying and baking, but still leave a series of bioactive microbial metabolites, which makes chocolate emit incredible flavor and aroma. Note that we should buy dark chocolate with high cocoa content without sugar.
Fermented meat products are made by fermenting meat with lactic acid bacteria. Bacteria involved in meat fermentation will produce biogenic amines, which are organic compounds that give fermented meat a unique flavor. Many fermented meat products are cold-cured, which means that some fermented meat products will carry beneficial microorganisms. However, the high salt content of many fermented meat products will inhibit the stability of probiotics.
Of course, these are only a few of the many fermented foods in the world today. So why should these foods be part of our daily diet?
Why eat some fermented food in moderation every day?
We know that in many traditional cultures, fermented food is the main content of daily diet. Eating these foods every day can maintain a stable supply of beneficial microorganisms in the gastrointestinal tract and have a great impact on our health.
Of course, many clinical studies show that most supplemented probiotics will not permanently colonize the gastrointestinal tract, and they will only play a short-term role when passing through the intestine. In other words, their influence on intestinal flora is usually not permanent. More importantly, there are still many factors that affect our intestinal flora all the time in our daily life.
Therefore, in this case, it is not important whether these beneficial microorganisms will permanently colonize the intestine if we add fermented food to our daily diet. Only by constantly ingesting these foods rich in probiotics can we give full play to our health benefits and better face the constant influence of daily life factors on intestinal flora.
Under what circumstances should you not eat fermented food?
Fermented food is healthy and nutritious for most people. However, in some health conditions, it is best to avoid eating fermented food temporarily, such as histamine intolerance and mast cell activation disorder, mycosis or chronic inflammatory response syndrome.
When histamine accumulates too much in the body, histamine intolerance will occur, which will lead to the damage of histamine metabolism and treatment pathway. This may lead to various discomfort symptoms, including diarrhea, blushing, headache, palpitations and allergies. Because many bacteria involved in food fermentation produce histamine as a by-product, fermented food often has a high histamine content. If you are already allergic to histamine, eating fermented food may increase the total histamine burden and aggravate the symptoms. After solving the root cause of histamine intolerance (such as intestinal flora imbalance) and reducing the burden of histamine on the body, fermented food can be gradually added to the diet.
Inactivation of mast cells can also lead to symptoms similar to histamine intolerance. However, this is a more complicated situation, involving abnormal activities of mast cells, histamine-releasing immune cells and other inflammatory mediators. Because the disorder of mast cell activation will also increase the histamine burden of the body, fermented food may also aggravate the symptoms until the potential causes of abnormal mast cell activation are solved.
People with fungal diseases should also avoid eating fermented food, because some fermentation processes will promote the growth of mold. This kind of people can tolerate some fermented foods mainly containing lactic acid bacteria, but they may need to avoid foods containing mold during fermentation, such as cheese, lobster sauce, miso, sufu, fermented meat products and so on.
Summary:
Fermented food is a long and precious part of food culture all over the world. These foods provide us with rich health benefits, and their unique flavor, aroma and texture also add luster to our diet.
In almost every region where we live, there are some fermented foods with local characteristics, which can be properly added to our three meals a day. Of course, there are also some noteworthy places:
First of all, many fermented foods usually contain a lot of salt, which will have a certain negative impact on our health, such as easily leading to an increase in blood pressure. This is also one of the reasons why people think that fermented food is harmful to health, so we should pay attention to proper intake.
Secondly, the production of most fermented foods is now separated from the traditional manual production and transformed into large-scale industrial production. In order to meet the needs of industrial production and people's increasingly picky taste buds, a large number of chemical additives may be used, which also makes fermented food lose some authenticity and soul. Therefore, pay attention to the ingredient list when purchasing and choose products without additives. If possible, you can try to make your own fermented food, which can not only enjoy the fun of the production process, but also be healthier, such as yogurt and kimchi. It is quite convenient to make it at home. But remember to pay attention to hygiene and avoid contamination by miscellaneous bacteria, especially pathogenic bacteria.
The pictures are all from the Internet.