Probiotics; A Simple Beginner’s Guide-2
Other health benefits
There are many other benefits of probiotics. They may help with the following conditions:
- Inflammation: Probiotics reduce systemic inflammation, a leading driver of many diseases (54).
- Depression and anxiety: The probiotic strains Lactobacillus helveticus and Bifidobacterium longum have been shown to reduce symptoms of anxiety and depression in people with clinical depression (55).
- Blood cholesterol: Several probiotics have been shown to lower total and LDL (bad) cholesterol levels, although the research remains controversial (56).
- Blood pressure: Probiotics may also cause modest reductions in blood pressure (57Trusted Source
- Immune function: Several probiotic strains may enhance immune function, possibly leading to a reduced risk of infections, including those that cause the common cold (58Trusted Source
- Skin health: There’s some evidence that probiotics can be useful for acne, rosacea, and eczema, as well as other skin disorders (60).
- Anti-aging. Though research is extremely limited, there’s evidence that probiotics have the potential to extend lifespan by increasing the ability of cells to replicate themselves (61).
This is only a small slice of probiotics’ benefits, as ongoing studies indicate a wide breadth of potential health effects.
SUMMARY
In addition to their potential effects on weight loss, digestion, and neurological disorders, probiotics may improve heart health, immune function, and symptoms of depression and anxiety.
COVID-19 and probiotics
Some researchers propose that improving the gut microbiome via probiotic supplementation and diet may be a strategy to fight and treat an infection with the novel coronavirus SARS-CoV-2. This infection can cause COVID-19, which stands for coronavirus disease 2019 (62Trusted Source
).
COVID-19 is known to damage the body’s immune defense through a “cytokine storm” of excessive inflammatory cytokines. This is believed to be the main cause of deteriorating health and even death (63).
Because intestinal flora have been shown to strengthen the immune system and fight inflammation, researchers think probiotic supplements may help speed recovery from coronavirus by inhibiting or limiting this “cytokine storm” (64).
Also, people with COVID-19 have reported gastrointestinal symptoms, such as diarrhea, nausea, vomiting, abdominal pain, and loss of appetite (65).
Some researchers theorize that probiotics could help prevent the coronavirus by blocking the angiotensin-converting enzyme (ACE) receptor where the SARS-CoV-2 pathogen enters the body to invade gastrointestinal cells (66Trusted Source
).
Another proposed link between COVID-19 and probiotics involves what is called the “gut-lung axis.” This is a system of communication and interaction between the gut and lung tissues, which occurs via microorganisms of the human microbiome (67).
Imbalances of the intestinal flora are known to be related to lung diseases and respiratory tract infections. Researchers suggest that correcting those imbalances may promote optimum lung health, which might help guard against pathogens like SARS-CoV-2 (68Trusted Source
, 69Trusted Source
).
Other research suggests that probiotic supplementation may promote antiviral activity in general to improve immune, pulmonary, and anti-inflammatory response that might help clear the SARS-CoV-2 infection (70, 71).
All these hypotheses are at the theoretical stage. Researchers say further studies are needed to confirm them.
One study advises caution, suggesting that not all probiotic strains will exert the same effects. It questions whether probiotic supplementation can alter the content of the gut microbiome enough to combat COVID-19 (72).
SUMMARY
Some current research proposes that improving the gut microbiome through probiotic supplementation and diet may help treat the SARS-CoV-2 infection that causes COVID-19. Research is preliminary, and much more data and clinical trials are needed.
Safety and side effects
Probiotics are generally well tolerated and considered safe for most people. However, regulations differ among probiotics, so you must be cautious when choosing a product.
Choosing probiotics
As you face the large selection of probiotics now available, you may feel overwhelmed. You’re not alone. The choice can be difficult.
In the United States, probiotics are generally sold as food ingredients, drugs, or dietary supplements. While the Food and Drug Administration (FDA) regulates each of these in different ways, most foods and supplements do not require approval before marketing (73Trusted Source
Regulations on probiotics vary greatly around the world, so ordering online from other countries is risky. Unregulated food items, cosmetics, and supplements are easy to find abroad, but their safety is unconfirmed.
Looking for companies that follow best practices, such as third-party testing, can help you find high quality supplements.
The best choice is to run your choice by your healthcare provider or ask for suggestions. They may be able to recommend products they know to be safe and effective.
Probiotics side effects
In the first few days of taking a probiotic supplement, you may experience side effects related to digestion, such as gas and mild abdominal discomfort (75).
However, after you adjust, your digestion should begin to improve.
In people with compromised immune systems, including those with HIV, AIDS, and several other conditions, probiotics can lead to dangerous infections (76).
If you have a medical condition, consult your healthcare provider before taking a probiotic supplement.
SUMMARY
Probiotic supplements may cause digestive symptoms, which should subside within a few days. They may also be dangerous for people with certain medical conditions.
Challenges facing researchers
Science has made tremendous strides in the past two decades toward understanding the roles that probiotics play in human health and disease. Still, probiotic research is in its infancy, and there’s much to learn.
For example, researchers in 2019 reported identifying nearly 2,000 previously unknown gut bacterial species. This was a major step toward categorizing the microbes living in the human gut (77Trusted Source
).
After identifying the microorganisms, the next challenge facing researchers is to associate the various species, subspecies, and strains of microbes with their effects on human health — and this is where things get tricky (78).
Though thousands of studies have assessed the health benefits of probiotics for many clinical conditions, the results often contradict each other (79, 80).
One reason for this is that methods for processing and analyzing probiotics data are not consistent around the world. This leads to conflicting research analyses of published data (81Trusted Source
The standardization of probiotics research is challenging because the human body contains a large and diverse set of microorganisms, which varies among countries — and even among individuals in the same country.
Plus, the bacterial strains themselves are constantly evolving, as are the health and environments of their human hosts.
Probiotics researchers face the task of classifying what might be trillions of ever-changing organisms in varied and evolving environments.
It’s only the development of computational analysis of the genomes of collective groups of microbes (called metagenomics) in the past two decades that makes this Herculean task possible at all (82).
Scientists must standardize a mountain of sometimes conflicting evidence from thousands of studies, and then translate that evidence into clear recommendations for therapeutic probiotic use (83Trusted Source
SUMMARY
Researchers are challenged with identifying all the microbiota in the vast and changing microbiome of the human gut. They also need to establish a system for standardizing research results to develop clear therapeutic recommendations for probiotic uses.
