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L. reuteri NCIMB 30242 Personalized Probiotics Regimen

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A holistic take on genetics, microbiome analysis, and lab tests can help maximize the benefits of dietary supplements. Find out how that can be accomplished with L. reuteri NCIMB 30242, a probiotic strain backed by clinical research for supporting normal cholesterol levels, bile metabolism, and heart health.

Disclaimer: This post is for informational purposes only. Please discuss your medical concerns with your doctor.

Is the Modern Lifestyle Killing Your Gut Microbiome?

Lactobacillus reuteri NCIMB 30242 belongs to a family of beneficial probiotics that seems to be leaving our gut microbiome with the modern lifestyle. The first L. reuteri species of probiotics was initially isolated in the 60s as a normal part of a healthy human gut, vaginal, and breast milk microbiome [1, 2, 3].

Yet, the abundance of L. reuteri in our microbiome has dropped over the past few decades. Scientists have linked this drop with the modern lifestyle: frequent antibiotics use, eating a Western diet high in processed foods, and living in a sterile and ultra-hygienic environment [1].

The decrease in L. reuteri has coincided with an increase in inflammatory diseases over the same period of time. Although evidence is lacking to suggest a cause-and-effect, scientists think that boosting L. reuteri may be one safe way to reduce an excessive inflammatory response and autoimmunity [1].


The drop in L. reuteri over the past few decades has coincided with the modern and medicalized lifestyle and an increase in inflammatory diseases. Boosting L. reuteri may support good health.

Personalized Probiotics: Is L. reuteri NCIMB 30242 Right for You?

We recommend taking into account all the following analyses (or as many as possible) to get a complete picture of your gut microbiome and overall health:

  • Gut microbiome testing
  • Blood tests
  • Genetics testing
  • Health status checkup

Talk to your doctor if you’re not sure how to start. Selfdecode also offers genetics, blood labs, gut microbiome interpretation along with personalized recommendations.

Microbiome testing

According to the research, people with the following gut microbiome parameters may benefit from L. reuteri NCIMB 30242 supplementation [4, 5, 6]:

  • Microbiome imbalance/gut dysbiosis
  • Low microbiome diversity
  • Low microbiome richness
  • Poor bile acid metabolism (low free bile salts)
  • Few lactic acid bacteria (low Lactobacillus spp.)
  • Low Firmicutes levels
  • Decreased ratio of Firmicutes to Bacteroidetes

Interpreting your gut microbiome test results for the first time can be intimidating. Let’s take a look at some of these markers and what they mean for your health and probiotic choice.

Why your Firmicutes to Bacteroidetes (F/B) ratio matters

In one study, Lactobacillus reuteri NCIMB 30242 increased free bile acids, total bile acids, and the ratio of Firmicutes to Bacteroidetes (F/B) gut bacteria in 10 healthy people over 4 weeks [5].

Until recently, though, scientists thought that a low F/B ratio was desirable. That’s not the case. New studies reveal that the ideal ratio depends on a person’s health status and disposition.

Cons of a low F/B ratio

A decreased F/B ratio has been linked with inflammatory bowel disease (IBD) in several studies. People with depression also have decreased Firmicutes, according to one study [5, 6, 7].

Other conditions associated with low F/B and poor gut microbial diversity include type 1 diabetes, lupus, chronic fatigue syndrome, old age, and antibiotics use [8, 9, 10, 11, 4].


L. reuteri NCIMB 30242 increases the F/B ratio and microbial diversity. IBD, depression, and other conditions are linked with low F/B and low microbial diversity.

Cons of a high F/B ratio

On the other hand, some people with IBS and obesity tend to have a high F/B ratio compared to healthy controls. The association was especially relevant for diarrhea-predominant irritable bowel syndrome (IBS-D) and IBS with bloating in several studies [12, 13, 14, 15, 16, 17].

It’s important to note that people with IBS usually also suffer from low microbial diversity and high Clostridia and Clostridiales. This points to an overall unhealthy gut microbiome [12, 13].

Other conditions linked with a high F/B ratio include heart disease and fatty liver disease [18, 19].

That doesn’t mean that a high F/B ratio causes heart and liver disease or that people who suffer from these diseases should avoid Lactobacillus probiotics. On the contrary, Lactobacillus reuteri NCIMB 30242 supports heart health [20].

Lactobacillus levels & IBS

All Lactobacilli belong to the Firmicutes phylum, including Lactobacillus reuteri NCIMB 30242. Lactobacilli are generally “good” bacteria, but the findings on their effects on IBS have been mixed.

For example, a review from 2019 of studies including over 1000 people in total found higher Lactobacillus levels in IBS patients. A review from 2020 including 1,340 people pointed to lower Lactobacillus in IBS patients, along with gut microbial dysbiosis [13, 21].

Due to the conflicting data, we suggest caution in people with IBS until more studies come out.

The Bottom Line

Most gut bacteria (80-90%) belong to either Firmicutes or Bacteroidetes [22].

The Firmicutes phylum is diverse and includes a combination of beneficial and potentially harmful bacteria.

That’s why looking at specific probiotic species within each phylum and their ratios can provide more meaningful information. New research should also help us understand how different probiotic species interact with each other and with health and disease [13].


IBS and obesity are linked with high F/B and low microbial diversity. Lactobacillus probiotics may still be beneficial in people with IBS, but we advise caution until more studies come out.

Blood lab results

In clinical studies, L. reuteri NCIMB 30242 lowered the following blood lab markers (linked with heart disease and inflammation) [20, 23, 24, 25, 26, 27]:

It also increased blood vitamin D levels (circulating 25-OH vitamin D) [28].


L. reuteri NCIMB 30242 supports normal blood vitamin D, LDL cholesterol, total cholesterol, CRP, and fibrinogen levels. These are standard labs your doctor can order.

How to find out whether you are a cholesterol hyperabsorber

Some evidence suggests that L. reuteri NCIMB 30242 may additionally benefit cholesterol hyperabsorbers: people who absorb too much cholesterol but produce little. This subgroup also tends to respond poorly to statins and better to Zetia [29, 30].

While a lipid panel (triglycerides and total, HDL, and LDL cholesterol) is useful, it doesn’t tell you your cholesterol absorption status [31].

You can find out whether you are a hyperabsorber by doing sterols testing. The sterols blood test measures [29]:

  • Cholesterol absorption markers (campesterol, sitosterol, and cholestanol), and
  • Cholesterol production markers (desmosterol and lathosterol)

You are a hyperabsorber if your values of cholesterol absorption markers are high. About 1 in 4 people are cholesterol hyperabsorbers [29].

On the other hand, you’re a hypersynthesizer if your cholesterol production markers are high.

Also, being older can make you more likely to be a hyperabsorber, especially if you are a woman past menopause [32, 33].

Ask your doctor about sterols testing because it’s still not commonplace but can be extremely useful in guiding treatment and supplementation [29].

Only a few labs run this test, like Boston Heart’s Cholesterol Balance Test and Mayo Clinic Laboratories [29, 34].


L. reuteri NCIMB 30242 seems to be a good choice for people who are cholesterol hyperabsorbers. You can find out if you are a hyperabsorber by doing sterols testing in specialized labs.


People with the following genetic makeup may benefit from L. reuteri NCIMB 30242 supplements:

  • Low ABCG5/ABCG8 [32]
  • Overactive NPC1L1 [32]
  • Overactive FXR [24].
  • Low FGF-19 [25, 35]
  • Low liver X receptor (LXR) [20]
  • APOE4 genotype (due to associations with cholesterol hyperabsorption) [36, 33]

According to studies, L. reuteri NCIMB 30242 likely blocks NPC1L1 and activates ABCG5/G8 receptors [20].

Blocking NPC1L1 reduces cholesterol absorption in the gut. Activating ABCG5/8 prompts liver cells to release more cholesterol that can be eliminated with the stool. People with less active ABCG5/8 or overactive NPC1L1 tend to absorb cholesterol and plant sterols in excess [20].

L. reuteri NCIMB 30242 may also turn “off” the farnesoid receptor (FXR) by releasing free bile acids via an enzyme called bile salt hydrolase. In turn, more cholesterol gets broken down and more bile acids get produced [20, 24].


L. reuteri NCIMB 30242 may support good health in people who are genetically predisposed to high cholesterol and plant sterols absorption and low free bile acids.

Health status and age

In addition to the health conditions and analyses mentioned above, it’s crucial to take a look at your complete medical history, age, and lifestyle.

L. reuteri NCIMB 30242 has FDA GRAS (Generally Recognized as Safe) status and is safe to consume daily for most people. Consult your physician before supplementing if you are pregnant or nursing, under the age of 18, or have a medical condition.

This probiotic strain has been tested in patients with high cholesterol, people with occasional diarrhea and functional gastrointestinal disorders, and in healthy adults. Clinical research suggests it may improve factors that promote cardiovascular, immune, gut, and overall health [20, 23, 28, 24, 25, 26, 27].

According to limited research and anecdotal clinical experience, L. reuteri NCIMB 30242 is safe to take along with statins and Zetia. However, little is known about its possible interactions with drugs in general [23].

Read more about the dosing and the clinical research backing L. reuteri NCIMB 30242 in this post.


L. reuteri NCIMB 30242 is safe for most adults. Consult your doctor before supplementing just in case, especially if you have a medical condition or take medications.

Buy L. reuteri NCIMB 30242 Probiotics

L. reuteri NCIMB 30242 is sold by Microbiome Plus+, a science-based probiotics and synbiotics company.


L. reuteri NCIMB 30242 may be a good choice for people with a low ratio of Firmicutes to Bacteroidetes (F/B), gut dysbiosis, poor bile salt metabolism, and genetics and labs that point to high cholesterol absorption. It’s safe for most adults, but be sure to double-check with your doctor first.

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