What are probiotics
Why to take probiotics
How to choose probiotic supplements

What are probiotics?

“Probiotic” is a term that has been coined to mean specifically live organisms that confer a positive health benefit when consumed.

This is in stark contrast to other bacteria that are consumed unintentionally that may not have any effect, or may be detrimental to one’s health.

Despite the strong scientific validation of probiotics, consumers often fail to sense any benefit of probiotic supplements. Research suggests that any lack of benefit probably has to do with the specific supplement used, and that the right supplement will be quite worthwhile.

Probiotics are typically bacteria that will take up residence in the digestive system, and tend to improve immune function and digestion, thereby affecting overall health.

Probiotics have been studied for their effects on metabolic syndrome, liver injury, inflammatory bowel diseases, autism, colorectal cancer, enteritis, immune modulation, allergies, atopic dermatitis and eczema, and more.

Probiotics for Immune Support

Why the digestive system is the center of good health

The digestive system is a large component of the immune system, especially for detecting threats that enter through the mouth and nose.

The small intestine, in particular, has many features that allow it to survey and “clean” incoming particles for anything that may be considered a threat to good health. The intestines also have mechanisms for presenting threats to the immune system.

The gut houses many different kinds of bacteria, which in combination are called “gut flora.” Gut flora refers to both the “friendly” bacteria (probiotics) that support good health and digestion, as well as “unfriendly” bacteria, such as e coli or strep bacteria.

The theory of inflammation mediated by gut flora holds that inflammation arises from either a lack of bacterial diversity in the gut, or an overgrowth of more aggressive strains – or both. Both of these conditions can make the immune system more sensitive or susceptible to activation.

what are probiotics

The gut flora can affect the immune response to incoming pathogens, and favorably changing the composition of gut flora can reduce the inflammation associated with immune system activation.

Any immune response includes inflammation - whether it is acute or chronic inflammation, and where it is located has to do with the frequency of the threat, and the immune system defenses that are employed.

Probiotics that change the gut flora can reduce the permeability of intestinal cells, thereby affecting which particles gain access to “deeper” portions of the body. When particles do not “seep” through the intestinal barrier, they are less likely to be presented to immune cells and initiate an inflammatory immune response.

In contrast, harmful bacteria send toxins throughout the body, and have been implicated in liver fibrosis and cirrhosis, among other health conditions.

To learn more about different probiotics that are associated with specific health benefits see our other article on the science of probiotics.

Why to Take Probiotic Supplements

Here are some general facts about probiotics that improve health:

  • There are bacterial strains associated with reducing or suppressing inflammation, and those include Lactobacillus and Bifidobacterium, as we all possibly some members of the Clostridium cluster XIVa.
  • Lactobacillus strains have been shown to improve the intestinal barrier, thereby reducing inflammation associated with the “invasion” of pathogens. Lactobacillus strains also counteract E coli bacterial strains: an example of the importance of maintaining a balance between “good” and “bad” bacteria in the gut.
  • Antibiotics that are prescribed to kill bacteria tend to be nonselective in their job. That is, antibiotics kill all bacteria indiscriminately – good and bad alike. Therefore, it is a great idea to take probiotics following an antibiotic regimen in order to reestablish healthy gut flora.
  • As an extra bonus, probiotics also can promote regularity, and can aid in the digestion of food, thereby improving the effectiveness of the digestive system and the removal of waste.
  • How to choose probiotic supplements

    There are seven Lactobacillus strains that are commonly used as probiotics commercially, and there are two strains of Bifidobacterium commonly used. However, the list of probiotics that could be included in a supplement and the possible combinations of probiotics in a supplement is nearly infinite.

    See our article on different probiotics for specific health complaints to determine which probiotic strains might be best for you.

    Here are some general tips about choosing a probiotic:

  • Choose probiotics that have scientific merit for your particular health goals. See our article on different probiotics for specific health complaints to help identify which strains you would like to have in your probiotic supplements.
  • Aim for at least 2 billion cultures of each strain. If a brand only lists the total number of cultures rather than counts for each strain, it is likely that the supplement is overloaded with the cheaper strains, and carries a minimal amount of the other less common strains. As a result, I tend to avoid probiotic supplements that do not specify the number of cultures for each strain. 2 billion cultures are accepted as a good “dose” for the bacteria to establish themselves in the gut over time. Consider adjusting the number of capsules that you take in order to meet this goal.
  • Look for products that are “enteric coated” to ensure that they will make it to the small intestine without being digested. Take probiotic supplements on an empty stomach or with a light meal for the same reason. Powdered probiotics are great, especially for little ones, but just be sure that these are taken on an empty stomach with plenty of water (at least 30 minutes before a meal, and at least 2 hours after a meal).
  • FOS (fructooligosaccharides) and inulin are often added “bonuses” in probiotic blends. These are substances that are not probiotics themselves, but rather help probiotics establish themselves in their new home: your gut.
  • According to the recommendations of your physician, consider gradually working up to a maximal dose in the beginning, and tapering off to a minimal dose once the benefits have reached a plateau. Ideally, the probiotics will take up residence in your gut and proliferate, making probiotic supplements a requirement only for maintenance, or following an antibiotic regimen. How long it will take for probiotic levels to reach a healthy balance depends on individual dietary, lifestyle, and health factors; as well as the probiotic supplement.
    • Just a bit about soil-based probiotics, or soil-based organisms: these beneficial bacteria that are derived from the soil have historically been a part of our diet subconsciously through the consumption of untreated, raw fruits and vegetables. Typically, these probiotics do not take up permanent residence in the gut, but rather, contribute to digestive health for brief times as they are passing through (up to weeks). Therefore, these types of probiotics must be taken regularly. There is not much scientific support for the clinical benefits of these types of probiotics, but there is a lot of antecdotal support for their use – people claiming relief from chronic fatigue syndrome, diabetic foot sores, gulf war syndrome, allergies, tuberculosis, and more. While the scientific research is sparse, the idea of eating “with nature,” or eating as our ancestors did is appealing to many. There is a belief that modern pesticides, fungicides, and soil conditions have reduced the number of these probiotics naturally occurring in our diets. However, there is not any scientific data that would encourage me to purchase them, personally.

    What bacteria are in our digestive tracts

    The bacterial composition of fecal matter or saliva can be analyzed using cultures or genetic sequencing. Genetic analysis of fecal matter from 124 people revealed that there are at least 160 different types of bacteria housed in the gut. Many of the bacterial strains were common to among most people, while only a few strains were less common.

      It is important to note that the composition of bacterial flora differs along the length of the digestive tract. That is, the bacteria found in the saliva will differ from those found in the small intestine, which are still different from those found in the colon. Worldwide comparisons show that the prevalence of specific bacteria differs among geographic locations, as well, which adds to the potential complexity when reviewing the scientific research and understanding the role of probiotics. Also, there are even genetic differences among bacteria within identical strains. I point this out because a lot of probiotic research or research reviews may not take into consideration the diversity of bacterial strains that are under consideration for health benefits, and we may have no way of knowing which genetic modification of a strain is included in our probiotic supplements.

    Always remember to maintain open communication with your physician and pharmacist about any supplements you are taking or plan to take. Few side effects have been reported from probiotic supplements, and most are mild gastrointestinal complaints (bloating, gas, changes in bowel movements) that clear up once the probiotic supplement is stopped or replaced with a different brand.

    Do you take probiotics? Tell us: What do you consider to be the best benefit? How do you choose which probiotic supplement to use?

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    Hakansson A, Molin G. "Gut microbiota and inflammation." Nutrients. 2011; 3(6): 637–682.

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