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Gut microbiome influences your entire body

Phages Boost the Benefits of Probiotics

In a clinical study, combining a probiotic blend with bacteria-killing phages improved gastro- intestinal inflammation symptoms and reduced colon pain more than the probiotic alone.

Scientifically reviewed by: Gary Gonzalez, MD, in December 2023. Written by: Laurie Mathena.

The impact of the gut microbiome influences our entire body.

Imbalances in microbiome composition have been linked to a host of common disorders including inflammation, autoimmunity, metabolic conditions, brain chemistry, and more.1-3

The good news is that the balance of the gut microbiome can be shifted towards one associated with better health.4-6

One way to do this employs the combined use of probiotics and bacteriophages or "phages."

Phages are tiny packages of DNA or RNA wrapped in protein.

Each type of phage naturally attacks only specific types of bacteria.7-9 By selecting specific phages, it is possible to target specific, potentially harmful bacteria in the digestive tract.

This allows a dual-approach strategy of using probiotics for their beneficial effects, while reducing competition from bacteria, of which we want less.

How Gut Health Impacts Overall Health

Gut bacteria affect almost all aspects of human health.

Researchers have estimated that a healthy adult individual's intestines host about 160 distinct bacterial species.5 The presence or absence of certain species can have dramatic consequences.10,11

An enormous range of gut bacteria is necessary for optimal health. One important health-promoting property of some bacteria in the gut is the ability to produce short-chain fatty acids, compounds that have shown anti-inflammatory, immune-supportive, and neuroprotective activity, among other benefits.12

Certain factors, including advancing age,13 poor diet,13 stress,13 antibiotic use,13 and lack of physical activity,10 can cause our microbiomes to become imbalanced, a state known as dysbiosis.14

This imbalance is associated with worse health.4 Scientists have linked dysbiosis to colon infections, antibiotic-associated diarrhea, irritable bowel syndrome, autoimmune disease, allergic conditions, and obesity.15,16

Other harmful microbes in the gut can cause infections, inflammation, and gastrointestinal discomfort, and appear to contribute to the risk for chronic disease.13,17

Even in otherwise healthy individuals, a gut bacteria imbalance can trigger the development of digestive symptoms like diarrhea, gas, bloating, and abdominal pain.18

Gut bacteria even appear to play a role in the metabolism of neurotransmitters such as serotonin, a mood-regulating hormone.19 That could help explain why people with certain gastrointestinal disorders have a higher risk of mental health conditions like depression and anxiety.1,20

Shifting the gut microbiota toward a healthy balance can ease digestive issues and improve overall health.

The Benefits of Probiotics and Phages

Research has established the many and varied benefits of taking oral probiotics. Lactobacillus and Bifidobacterium, two of the most common probiotics, help ease symptoms of certain gastrointestinal diseases.21

Bacteriophages are lesser-known tools that help promote gut and overall health.22

The term "bacteriophage" literally means "bacteria eater." Phages are selective killers, only targeting and destroying specific bacteria.7,9,23

The phages can allow beneficial bacteria to flourish and grow at a greater rate by removing competing harmful species.24

Phages were discovered almost a century ago and were recognized by the FDA as early as 1958 as safe to use to help protect foods against the growth of undesirable bacteria.25 Because they exclusively target bacteria and not animals or humans, and as suggested by their safety to use in the food supply, phages pose no health threat to humans.

However, research into phages as therapeutic agents in human infections fell out of favor with the discovery of antibiotics.26 Today, as the threat of antibiotic-resistant infections and superbugs has become more concerning, medical research is refocusing on the potential of phage therapy.

Phages have now been used in numerous human trials and therapeutic settings with no reports of adverse effects.27-32

Combining probiotics with phages holds great promise for gut health and other areas of health impacted by the gut microbiome. 

What You Need To Know

Improve the Microbiome with a Phage-Probiotic Blend

  • The mix of microbes in our gut has a huge impact on digestive and overall health.
  • Taking beneficial bacteria called probiotics can improve the balance of the gut microbiome.
  • Bacteriophages, called phages for short, are packages of DNA or RNA wrapped in protein. They can selectively kill harmful bacteria, allowing probiotic bacteria to flourish.
  • Combining phages with probiotics may boost the beneficial impact of the probiotic.

Human Trials

Researchers developed a targeted four-phage blend that can help rapidly decrease intestinal populations of the unfavorable bacteria E. coli, while boosting growth of beneficial bacteria.33,34

In a clinical study, scientists tested the impact of these bacteriophages on the gut microbiome and gastrointestinal inflammation. Healthy adults received either the four-phage blend (LH01-Myoviridae, LL5-Siphoviridae, T4D-Myoviridae, and LL12-Myoviridae) or a placebo daily for 28 days.34

Compared to placebo, the phage blend was associated with:34

  • Increases in beneficial bacteria in the gut,
  • Decreases in Escherichia coli (E.coli) bacteria, a common cause of diarrhea and other digestive problems, and
  • Decreases in interleukin-4, a marker of inflammation

This shows that phages can beneficially modify gut bacteria.

In another clinical study, researchers tested whether adding the four-phage blend to a common probiotic bacterium, Bifidobacterium lactis, could enhance the effects of the probiotic.33

Healthy adults received either B. lactis or that probiotic with the four-phage blend for four weeks. Compared to the probiotic-only group, the group that consumed B. lactis plus the phage blend had:33

  • Improvement in symptoms of gastrointestinal inflammation,
  • Reduction in colon pain,
  • A six-fold increase in beneficial Lactobacillus bacteria, and
  • Decreases in the gastrointestinal tract in the amount of Citrobacter and Desulfovibrio, and a trend toward a decrease of E. coli, intestinal bacteria associated with inflammation, gastrointestinal dysfunction, infections, and other potentially serious health problems.

These observations suggest adding phages to probiotics could support probiotic benefits and aid in the shift toward a more favorable gut microbiome.


An unhealthy imbalance of bacteria in the gut can negatively affect gut and overall health.

Probiotics taken as supplements have helped balance intestinal flora.

Taking an oral combination of probiotics and bacteriophages may improve the health of the gut microbiome.

Phages show promise in relieving the functional changes caused by gut microbiome imbalance. This may be especially valuable for aging individuals.

If you have any questions on the scientific content of this article, please call a Life Extension Wellness Specialist at 1-866-864-3027.


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