Do probiotics really work?

Are bacteria really harmful and useless? The answer is of course no. For example, probiotics are well known to everyone, and even probiotics have become a winning magic weapon for many mothers. Why are probiotics so popular? Are probiotics really useful? Let's talk about it today.

01. Why are probiotics so popular?

As probiotic products have been very popular in recent years, I will talk about this issue from the perspective of academic research. In fact, probiotics have always been very popular, but in recent years, with the explosion of scientific research on intestinal microorganisms, CNS-level articles can be said to be numerous, so probiotics have also taken the rocket and become the center of the health field.

Why have probiotics become so important? This requires a brief history of probiotics. Others have summarized it very well, so I will just quote it directly:

The word probiotics comes from Greek, meaning "beneficial to life". It was first used by Lilley and Stillwell of St. John's University in the United States in 1965 to describe substances secreted by microorganisms that can promote the growth of other microorganisms, corresponding to antibiotics.

Since then, its meaning has changed many times, and the definition given by the World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) is currently widely used: probiotics are live microorganisms which, when ingested in adequate amounts, confer a health benefit on the host.

From this we can see that probiotics is a very "smart" name, because from the very beginning, it is defined as "beneficial to the human body", so it is naturally effective, and those that have no effect are naturally not called "probiotics".

Seeing this, some people may ask, is this a deception of the nature of rhetoric? Probiotics are not effective, right? The answer is of course no. In fact, probiotics have been proven to have many effects.

02. The role of probiotics

As early as 1965, Lilley and Stillwell from St. John's University in the United States published a research paper in the famous academic journal Science, describing that secretions from microorganisms can act as growth-promoting factors, opening the precedent for research on the effects of probiotics [1]. Subsequently, a large number of studies have shown that probiotics have many beneficial functions, such as

1. Promote the absorption of nutrients. Probiotics are firmly integrated into our body, especially the digestive tract, which is of great significance for the absorption of nutrients. For example, probiotics can produce some meaningful enzymes to promote the digestion and absorption of food, thereby improving the absorption of beneficial nutrients such as protein and vitamins.

2. Improve immunity. Probiotics can produce some immune substances, such as antimicrobial peptides and bacteriocins, which can kill harmful bacteria and are very helpful in enhancing our immunity. In addition, probiotics can also stimulate the immune system in the intestines and enhance our immunity.

3. Relieve diarrhea. When traveling, poor acclimatization, bad eating habits, and taking antibiotics can disrupt the balance of intestinal flora and cause diarrhea. At this time, timely supplementation of probiotics can restore the balance of intestinal flora and relieve diarrhea symptoms.

Based on existing research results, there is relatively sufficient evidence that probiotics can prevent and treat viral diarrhea, diarrhea caused by antibiotics, traveler's diarrhea, diarrhea caused by Clostridium difficile, irritable bowel syndrome, inflammatory bowel disease, Helicobacter pylori infection, etc. In addition, probiotics also have a positive effect on other gastrointestinal, cardiovascular and cerebrovascular, tumor, female reproductive tract, chronic metabolic and psychological diseases.

In recent years, the research and application of probiotics, a type of microorganism that coexists with the human body, has penetrated into the medical field. A typical example is intestinal microbial transplantation, which we usually also call "fecal microbial transplantation." In the article "Improving regulation of microbiota transplants" published in Science in 2017 [2], the author gave an introduction that can give us some reference. Taking digestion as an example, we know that one of the characteristics of obese people is that they digest nutrients too well, which leads to excessive absorption of nutrients and makes them prone to obesity. Scientists have found that obese people and thin people have different intestinal microorganisms. Therefore, the method of intestinal microbial transplantation can directly change the absorption of obese people, thereby completely solving the problem of obesity.

Currently, intestinal microbial transplantation has entered clinical use. Compared with the harm caused by weight-loss drugs or surgery, intestinal microbial transplantation is safer and more effective.

03. What are the components of intestinal microorganisms?

Since the microorganisms in the intestine are so important, what exactly are they made of? The following is a picture of intestinal microorganisms from the Institute of Microbiology, Chinese Academy of Sciences.

How about it? Do they look familiar? Bifidobacterium? Lactobacillus? In fact, aren't these two the probiotics we are familiar with? Yes, it is true. These are the types of probiotics commonly added to probiotic products on the market. Let's learn more.

Lactobacillus : Lactobacillus is a type of bacteria that can ferment sugars to produce lactic acid. Sugars are one of our three major nutrients and are also our most common nutrients. The fermentation of sugars by lactic acid bacteria can directly promote our body's absorption, so lactic acid bacteria has also become the most common type of probiotics. Whether it is our favorite yogurt or various lactic acid drinks, they all contain lactic acid bacteria. In addition, some lactobacilli have additional functions, such as inhibiting the growth of harmful bacteria and promoting immunity.

Bifidobacterium : Bifidobacterium, the main function is to balance intestinal microorganisms. Since our bodies take in a lot of food and air every day, these substances are often mixed with a large number of microorganisms, which will impact the balance of our intestinal microorganisms. Bifidobacterium plays a role in maintaining the balance. It will retain microorganisms that are beneficial to the human body, such as lactobacillus, and remove those that are harmful to the human body, playing a biological barrier role. Therefore, bifidobacteria are also added to many probiotic supplements.

It is precisely because we studied intestinal microorganisms that we found that the dominant flora in the intestinal microorganisms include bifidobacteria and lactobacilli, which can coexist with humans for a long time, so researchers separated these flora and further studied them and found that these bacteria are indeed beneficial to humans. With the development of the market and industry, probiotics are increasingly used in the market, such as some of our common yogurts and probiotic preparations.

So, you see, the market's choice of probiotics is not random, most legitimate products have a source of evidence, and they have indeed obtained evidence to prove their scientific effects, which is why they are widely sought after. Of course, unreliable manufacturers are another matter.

04. Will probiotics be killed by gastric juice?

Having said that, I believe you already have some understanding of the effects of probiotics. However, some people may still have questions. After ingestion, probiotics will go through our digestive system, especially the highly acidic stomach. Will it kill the probiotics and make them ineffective?

In fact, there is no need to worry. Although probiotics will encounter stomach acid after entering the human body, a considerable number of them can still overcome obstacles and reach our intestines.

For example, this study titled "Environment dominates over host genetics in shaping human gut microbiota" was published in Nature in 2018 [3]. The authors found that environmental factors, rather than genetic factors, are the main factors in shaping intestinal microbiota. These environmental factors include gender, geography, drugs, diet, and lifestyle habits. In other words, these probiotics can reach our intestines. In fact, an intuitive understanding is that when we are in our mother's womb, we are basically sterile. After birth, there are a large number of microorganisms in the intestines. Where do they come from? They are ingested from the outside.

I believe that after reading this, everyone has already made their own judgment on whether probiotics are effective.

05. How to choose probiotic products in daily life?

For ordinary people, academic research is also to support a more convenient life. So, how do we choose probiotics?

1. Choose probiotic products from regular manufacturers and big brands. They are regulated by relevant departments. Most of the probiotic strains they add are allowed by regulations and have undergone multiple verifications. There is sufficient evidence to support their effectiveness.

2. Read the product description and choose probiotic products with high live bacteria count (the unit is CFU -- Colony-Forming Units) as much as possible.

3. Most probiotics should be refrigerated but not frozen, and the fresher the better. However, this does not mean that probiotic products cannot be stored at room temperature. In fact, many probiotic supplements on the market already have room temperature storage technology, which allows probiotic products to be stored at room temperature for a long time. Therefore, as for how to store probiotic products, it is recommended to store them according to the storage conditions specified in the product instructions and consume them as soon as possible within the shelf life.

Finally, let’s briefly summarize probiotics:

1. Probiotics are living microorganisms with a certain amount that can have a beneficial effect on human health. In recent years, the research in the academic community and the application in the market have been very popular! The intestinal flora is the largest in quantity, the most studied and used the earliest. Therefore, it is more familiar to ordinary people.

2. Probiotics themselves are beneficial for maintaining intestinal flora, and are also involved in many processes such as intestinal digestion, absorption, and immunity.

3. The purpose of treating diseases can be achieved by regulating intestinal microorganisms.

Ref

1. Lilly, DM & Stillwell, RH Probiotics: Growth-Promoting Factors Produced by Microorganisms. Science (80-. ).147, 747 LP-748 (1965).

2. Hoffmann D, Palumbo F, Ravel J, et al. Improving regulation of microbiota transplants[J]. Science, 2017, 358(6369):1390-1391.

3. Rothschild D, Weissbrod O, Barkan E, et al. Environment dominates over host genetics in shaping human gut microbiota[J]. Nature, 2018.