Research Over Despair

I am always glad to receive letters from people who, despite facing real difficulties, are motivated to understand their condition and actively look for solutions. This letter was one of those.

It came from a young person who had lived with PATM (People Allergic to Me) for just over a year. In that short time, the condition had disrupted education, lab work, friendships, and mental health. Like many others with PATM, this individual had been told - explicitly or implicitly - that what they were experiencing might not be real.

What struck me most was not the suffering (which, sadly, is familiar), but the decision that followed: instead of giving up, they chose to learn, to research, and to ask whether science might eventually provide answers - not only for themselves, but for others.

Below is a modified, bulletized and anonymized version of my response to their questions, shared here because many patients ask the same things.

Why is PATM still an undiagnosed condition?

PATM is often described as “undiagnosed,” but a more accurate term would be not formally recognized.

For a condition to become a recognized clinical entity, several things usually need to be in place:

• a consistent case definition

• reproducible, objective measurements

• and a plausible pathophysiological mechanism that can be validated by multiple independent groups

At present, PATM does not yet meet all of these thresholds.

One major challenge is heterogeneity. The presentation varies widely from person to person, and triggers differ depending on environment, exposure, and individual biology. Another major obstacle is that current clinical workflows are poorly suited to capture intermittent, airborne chemical events. Many patients describe symptoms that occur in bursts—so a clinical visit may appear “normal,” even when the lived experience is not.

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What would it take to achieve a formal medical diagnosis?

Large clinical trials can help, but they are rarely the starting point.

The real bottlenecks are:

• reproducible measurement methods

• defining subtypes rather than assuming a single mechanism

• capturing the episodic (“bursty”) nature of emissions

A well-designed, multicenter observational study—with standardized sampling protocols and careful timing relative to symptoms—may be a more realistic bridge step than jumping directly to intervention trials.

An official diagnosis could be beneficial. It can legitimize patients’ experiences in clinical settings, redirect care away from reflexive psychologization and attract more serious research attention. But such a diagnosis has to be built on solid evidence to endure.

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Is toluene the main irritation-causing substance?

It is unlikely that there is a single universal compound responsible for PATM.

Research on skin gas emission profiles is important because it demonstrates measurable chemical differences, but the broader picture likely involves multiple emitted mixtures and multiple subtypes. In some individuals, compounds such as toluene or related aromatics may contribute to irritation-like symptoms; in others, different chemical patterns may dominate.

Another key factor may be differences in detoxification or clearance. Some people appear more susceptible to everyday exposures—such as secondhand smoke, solvents, or indoor VOCs—not because exposure is higher, but because metabolism and elimination differ.

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What can patients realistically try on their own?

I generally recommend starting with low-risk, high-information approaches:

Structured symptom and exposure logging

Tracking timing, diet, stress, environment (workplace, vehicles, indoor air), laundry and personal care products, and proximity to smoke or solvents can help identify repeatable patterns.

Basic medical rule-outs

Even when PATM is the primary concern, it is important to evaluate common contributors to odor or irritation-related conditions, such as reflux, sinus disease, metabolic or endocrine issues, liver and kidney function, medication effects, and dermatologic conditions.

Environmental controls

VOC-related problems are often exposure-amplified. Fragrance-free products, avoiding solvent-heavy cleaners, improving ventilation, and using HEPA plus activated carbon filtration can reduce background “noise” and make patterns easier to recognize.

I generally advise caution with high-risk or expensive interventions unless there is a clear rationale for a particular subtype.

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What about fecal microbiota transplants (FMT)?

FMT is scientifically interesting but should be approached with caution. It is not a general solution for PATM and carries nontrivial risks. If considered at all, it should be under appropriate medical supervision and based on a specific, individualized hypothesis—not as a last-resort experiment.

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Are microbiome or skin-gas profiling tests useful?

They can be, if used carefully.

• Gut microbiome profiling may provide clues, but interpretation is still limited and should always be paired with symptom timelines, diet, and repeat measurements.

• Skin or exhaled gas profiling is conceptually promising because it targets the suspected output directly. However, episodic emissions make timing critical, and passive sampling methods may miss short-lived events.

The usefulness depends less on the technology itself and more on study design.

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Would wearable or portable gas sensors help?

In principle, yes. Continuous or frequent measurement could finally correlate chemical signatures with symptoms and environmental context.

In practice, true GC–MS–grade performance in a wearable format remains extremely challenging. Field measurements are complicated by changing ambient air, and episodic emissions require high time resolution and careful baseline correction. The idea is sound; the technology is still catching up.

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Could funding agencies support this kind of work?

Possibly more so now than in the past.

Historically, conditions that primarily affect quality of life rather than mortality have struggled to gain funding. When I first applied for support nearly two decades ago, the problem was explicitly described as “not important enough.”

Today, there is broader recognition of the impact of stigma, mental health, and chronic quality-of-life impairment. Advances in exposomics, microbiome science, and wearable sensing technologies make it easier to frame this work as high-risk, high-reward, particularly if the focus is on measurement platforms, subtyping, and mechanism rather than a single compound.

Much of this may sound like a list of obstacles. But compared with even a decade ago, the path forward is clearer.

If PATM turns out not to be one condition but a family of related ones, that is not a failure of science—it is a more accurate description of biology. Progress will likely come not from searching for a single universal cause, but from building frameworks that can accommodate diversity, intermittency, and complexity.

And sometimes, progress begins with a patient who decides that understanding is better than silence.

AI meets MEBO

After a bit of a break since our first podcast back in March, we’re excited to return with a brand new episode for the MEBO and PATM community.

In this video, we’re exploring a big question: Can patients themselves use AI to help uncover potential causes, connections, and treatments for their symptoms?

The episode was generated by NotebookLM, based on our own research and the outputs of multiple large language models answering real questions from patients and researchers about these conditions. It’s a very good discussion overall - balanced, empathetic, and realistic about the challenges - but there are a few small hiccups.

For example, the video says that the paper "Cutaneous Bacteria in the Gut Microbiome as Biomarkers of Systemic Malodor and People Are Allergic to Me (PATM) Conditions" was published in Frontiers in Psychiatry in 2022. In fact, it appeared in JMIR Dermatology, a peer-reviewed journal, but one that isn’t indexed in PubMed - so it often doesn’t register in medical literature searches. Interestingly, when we asked half a dozen more LLMs about this paper, none knew much about it. Some even called it “groundbreaking” or “a beacon” without actually having the details, and a few hallucinated links that don’t exist.

PATM and MEBO are still often misclassified or linked to Olfactory Reference Syndrome, but there is growing recognition that underlying microbial dysbiosis or metabolic disorders may play a role.

Still, the bigger picture is encouraging: LLMs are improving, and that gives hope for people living with under-researched, heterogeneous, and often misunderstood conditions. While this podcast focuses a bit more on social and emotional support than on treatment options, that’s also an essential part of living with these conditions - and it makes this video worth watching.

Let’s dive in and see what AI can - and can’t - offer us right now.

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PATM and Its Unbearable Reality

Condition that lacks a formal name can isolate you from the world. 

Josephine Franks brings to light the deeply isolating and misunderstood world of those living with PATM. This phenomenon causes people in proximity to sufferers to develop hay fever-like symptoms, including coughing, sneezing, and itchy eyes. 

Franks shares the stories of individuals like Medinah, a young woman whose condition confines her largely to her home, and Fahima, who has adapted her lifestyle to avoid triggering reactions in others. These personal accounts reveal the immense physical, emotional, and social toll of PATM. Sandra, a long-time sufferer, describes how the condition has led to anxiety, depression, and career setbacks, while Amir openly speaks about the profound loneliness and mental health challenges he faces.

While the article does not address our microbiome and metabolome findings, investigations by our scientists have uncovered significant heterogeneity in sufferers, complicating the search for patterns or consistent biomarkers. Communicating our research findings to the broader scientific community and securing adequate attention remain major hurdles.

Read the full article to learn more about the challenges, resilience, and some prior science surrounding this enigmatic condition: Read Josephine Franks's article on Sky News.

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Exhale The Difference: Propylene Oxide as a Game-Changer in Identifying Idiopathic Malodor Conditions

A new study posted on MedrXiv sheds light on the potential of breath analysis as a powerful, non-invasive diagnostic tool for Trimethylaminuria (TMAU) and TMAU-like conditions. One of the most interesting observations is the detection of Propylene Oxide in exhaled breath suggesting its delayed elimination and offering a promising marker for misunderstood and underdiagnosed conditions.

TMAU-like (yet negative to choline-challenge-based test) and "People Are Allergic To Me" (PATM) conditions, characterized by the emission of odorous or irritating Volatile Organic Compounds (VOCs), have long challenged the medical community due to the lack of non-challenge-based diagnostic procedures.

Using advanced gas chromatography-mass spectrometry, researchers analyzed the breath of 23 individuals exhibiting TMAU-like symptoms. They discovered that Propylene Oxide, alongside other VOCs, some of which were previously associated with PATM, can effectively discriminate between individuals who have tested positive for TMAU at some point and those who have not. This method demonstrated impressive accuracy, precision, and recall rates, making it a potential cornerstone for future diagnostic strategies.

Propylene Oxide's presence in breath samples particularly stood out in the study. This compound was more abundant in individuals that never tested positive for TMAU, potentially pointing to unique metabolic processes or environmental interactions that could be pivotal in understanding and managing TMAU-like conditions.

Propylene Oxide (PO) is a prevalent chemical found not only on Earth, owing to its widespread use in industrial and consumer applications, but also in the Milky Way. It leaves more significant marks on the human body than previously thought. Mass production contributes to its omnipresence, and exposure can occur through various sources such as cellulose acetate film, wood shavings, and paper cups. Despite efforts to eliminate gas residues, accidental exposure still occurs, particularly among workers involved in sterilization processes. Additionally, foods treated with PO as a fumigant may contain residues of the chemical.

PO has been detected in human breath following exposure to Propylene (PE), a combustion product found in forest fires, cigarette smoke, and vehicle exhaust. Indoor exposure is typically higher than outdoors due to residential activities like cooking, and urban areas tend to have higher concentrations than rural regions. Workers in specific industries may face elevated exposure levels, such as firefighters and refinery plant operators. PEG in cosmetic products can also be contaminated with propylene oxide. Furthermore, Propylene Glycol (PG) in cigarettes and e-liquids can be converted to PO, contributing to exposure.

Other compounds mentioned in the paper were markers of oxidative stress Hydroperoxide, hexyl; Hexanal; Decane, 2-methyl-; Tetradecane; Decane, 2,6,6-trimethyl- and D-limonene. 2,2,3-trimethylnonane was one of compounds associated with breath odor. 

This research emphasizes the need for personalized diagnostic approaches, considering the significant variability in VOCs among individuals. Such tailored strategies could lead to more accurate diagnoses and better management of conditions that currently lack specific treatments.

REFERENCES

Irene S. Gabashvili 2024 Propylene Oxide in Exhaled Breath as a Marker for Discriminating TMAU-like Conditions from TMAU medRxiv 2024.04.11.24305677; doi: https://doi.org/10.1101/2024.04.11.24305677

Irene S. Gabashvili 2024 Biological Factors Influencing Individual Responses to Propylene Oxide: A Systematic Review of Exogenous Exposure, Endogenous Production and Detoxification

medRxiv 2024.02.15.24302622; doi: https://doi.org/10.1101/2024.02.15.24302622

Open-Source Project: OSF | Biological Factors that Influence Individual Responses to Environmental Epoxides DOI 10.17605/OSF.IO/W7682

Rare Diseases in the Era of High-Cost Drug Development

We are currently witnessing a remarkable era in medical innovation, marked by rapid advancements and transformative developments. Yet the medical community is often unable to tell what works and what doesn’t. As the complexity of medical treatments increases, the importance of distinguishing reliable therapies from ineffective ones becomes ever more crucial. In this context, robust data collection and sophisticated analysis are indispensable tools.

In recent years, the trend in clinical trials has shifted towards smaller studies focusing on diseases that either attract substantial health insurance reimbursements or predominantly affect affluent populations. This shift is largely driven by the expectation of high drug prices post-development. However, this leaves a significant gap in research and treatment for conditions like Metabolic Body Odor (MEBO) and "People are allergic to me" (PATM). These conditions disproportionately impact individuals who may find it challenging to achieve financial security due to the nature of their ailments.

In 2008, a community survey by pharmacist Arun Nagrath highlighted a lack of confidence in medical advice among patients. Fast forward to the present, and while medical practitioners may exhibit greater confidence, their assurance is not always underpinned by evidence. This is evident in the prescription of costly tests, which clinicians may struggle to interpret or follow up effectively.

The landscape of self-treatment is continuously evolving. Popular remedies change over time, and the effectiveness of these treatments varies widely. In 2008, probiotics and Chlorophyl/Copper Chlorophyllin products were at the forefront. However, some patients reported that their odor issues worsened after using these remedies (as indicated by the red area in the corresponding pie chart, compared to green for effectiveness and gray for uncertainty). Many patients found that perfumed products exacerbated their condition, including about half of reported deodorants, though the other half was suitable types. Remedies once popular, like Mushroom extracts such as ProM and Champex, Activated Charcoal, Baking Soda and Hydrogen Peroxide have faded from the discussion. Vitamin B2, although used by fewer than a quarter of respondents in 2008 and found effective by some, remains a favored treatment. Oldenlandia and Coconut oil were found useful by small fraction of respondents. Somebody even used Bleach to clean themselves and found it to make things worse.  Interestingly, certain drugs intended for other conditions were reported to have secondary effects on odor – beneficial in cases like Prilosec and Probathine, and detrimental with Anxiolytics, Antidepressants, and Antivirals, the latter aligning with recent findings related to the COVID-19 vaccine. Antifungals were used by a few and were never found to worsen condition. Neither did Folic acid, Zinc, Calcium and Magnesium.  There were cases when digestive enzymes, contraceptives, and baking soda treatments made things worse. 

Interest in resveratrol, a compound present in red wine, reached its zenith in the late 2000s and early 2010s. During this period, the MEBO community extensively used and promoted this compound. In the mid-2010s, DMB became a focal point of discussion for many, while Fluxovas entered the scene and began to be mentioned starting in 2020.

While the popularity of probiotics endures, there is a noticeable shift towards personalization. Individuals are increasingly acknowledging the significance of identifying probiotic strains that harmonize with their unique physiology and health objectives. Our microbiome study unveiled that individuals with higher cutaneous bacteria (and total bacteria) abundances in the gut benefited from reducing microbial diversity and overall bacterial counts. In contrast, those with lower abundances found advantages in increasing microbial diversity. This highlights the absence of a universal solution for probiotics.

This evolving self-treatment scenario emphasizes the pivotal role of precision medicine, considering individual genetic, environmental, and lifestyle influences for disease treatment and prevention. Conditions like TMAU, MEBO, and PATM, lacking standardized effective treatments, emphasize the pressing need for more nuanced and targeted approaches.

Precision medicine, gaining popularity, particularly in tandem with Artificial Intelligence approaches this year, marks a departure from one-size-fits-all strategies. It relies extensively on data, specifically genomic, microbiome, and metabolomic data, to tailor treatments to individual patient needs. This patient-centric approach promises to revolutionize treatment strategies, especially for those with previously under-researched and underserved medical conditions.

MEBO's causes remain largely unknown, and without clear diagnostic criteria, it is often referred to as idiopathic malodor. This uncertainty mirrors the earlier challenges in diagnosing conditions like IBS, which was once seen as a diagnosis of exclusion. Today, the importance of ruling out other diagnoses through tests is recognized.

MEBO is a poignant example of a rare condition that can severely impact an individual's ability to pursue a career and achieve financial success. This condition is not only socially debilitating but also lacks effective diagnostic and treatment options. Diagnostic studies for such rare conditions are prohibitively expensive, and the lack of effective therapies exacerbates the problem. Moreover, the large heterogeneity within the patient population makes finding a one-size-fits-all solution particularly challenging.

So, what should be done in this scenario? First and foremost, there's a need for increased funding and research attention towards rare diseases like MEBO. This could be facilitated by incentivizing pharmaceutical companies through tax breaks or grants to undertake research in less profitable but socially significant areas.

Secondly, fostering collaborations between research institutions, pharmaceutical companies, and patient advocacy groups can create a more holistic approach to understanding and treating these conditions. Such collaborations can also help in the collection of more comprehensive and diverse data, and better ways to collect it, which is crucial given the heterogeneity of conditions like MEBO. 

Thirdly, the role of government and healthcare policymakers is critical. They can implement policies that encourage research and development in neglected areas, ensuring that the healthcare system is inclusive and caters to all, regardless of the financial implications or rarity of the condition.

Lastly, leveraging technology and innovation in medical research can also provide new avenues for diagnosis and treatment. For example, artificial intelligence and machine learning could be used to better understand complex conditions like MEBO, potentially leading to more effective and personalized treatments.

So far there’s never been any real emphasis on making clinical trials better or easier to conduct. Our goal, as a society, seems to be to manufacture more and more sports cars and to drive them faster and faster into the mud.

We hope that the healthcare industry and policymakers work together to ensure that all patients, regardless of their financial status or the rarity of their condition, have access to the treatments they need.

REFERENCES

This is biology's century. We're not ready for it (statnews.com)

Better Trials. Someday. | Science | AAAS

Gabashvili IS. The Incidence and Effect of Adverse Events Due to COVID-19 Vaccines on Breakthrough Infections: Decentralized Observational Study With Underrepresented Groups. JMIR Form Res. 2022 Nov 4;6(11):e41914. doi: 10.2196/41914. PMID: 36309347; PMCID: PMC9640199.

Gabashvili IS. Cutaneous bacteria in the gut microbiome as biomarkers of systemic malodor and People Are Allergic to Me (PATM) conditions: insights from a virtually conducted clinical trial. JMIR Dermatol. 2020 Nov 4;3(1):e10508. doi: 10.2196/10508. https://derma.jmir.org/2020/1/e10508/ 

Gabashvili IS. Artificial Intelligence in Biomedicine: Systematic Review

medRxiv 2023.07.23.23292672; doi: https://doi.org/10.1101/2023.07.23.23292672

Chronicles of Community-Driven Research: The Evolution of MEBO and PATM Studies

In the ever-evolving landscape of medical science, the untangling of medical mysteries often hinges not just on technological advancements or expert researchers, but on the active involvement of community members. Community efforts have been instrumental in the identification and understanding of elusive conditions MEBO (Metabolic Body Odor) and PATM (People Are Allergic to Me).

Late 1990s - early 2000s: The Dawn of Online Support Forums 

Before the conditions were officially named, online forums like MSN Body Odor Support Forum, ibsgroup.org, Yahoo TMAU group, and Curezone BO & Halitosis and TMAU forums served as early platforms for sufferers to discuss their symptoms. 

At this time, Trimethylaminuria (TMAU) was a scarcely recognized condition, and diagnostic tests were both costly and geographically limited. Trimethylaminuria support group, later established as foundation raises 35K and awards it to Dr. George Preti of Monell Center, the world’s only independent, non-profit scientific institute dedicated to interdisciplinary basic research on the senses of taste and smell.

2006-2007: Birth of MEBO and PATM Communities

In 2006, the acronym "PATM" was first coined by a sufferer, and by 2007, a dedicated PATM community was established on MedHelp. The initial post was reposted in PATM forum and garnered over 8,800 responses, signifying the start of a community-led initiative to explore the condition. While the term FBO (fecal body odor) emerged earlier and is still used on online forums,  it is often avoided due to its less appealing connotation. MEBO was coined by another individual suffering from a similar undiagnosed condition. This further fueled community-driven research and knowledge sharing among those affected.

2008: Broadening the Dialogue

The blog Bloodbornebodyodorandhalitosis.com is launched, later transitioned to meboblog.com. This year also saw more in-person meetups and community surveys, including one by pharmacist Arun Nagrath that received about 100 responses. 95% of responders was trying to seek medical help, over 90% thought that their doctor was not knowledgeable nor confident in their recommendations. 

2009: Formalizing Research Efforts

MEBO Research Charity was founded in both the UK and Florida, spearheaded by Maria de la Torre. The first collaborative study with UK's Biolab was initiated, focusing on blood and urine tests. The results were subsequently published on the MEBO blog and clinicaltrials.gov (NCT02692495, principal investigator: Irene Gabashvili).

2010: Unveiling the Microbiome and Genetic Factors

At MEBO's 1st annual conference, held in Nashville, Dr. Gabashvili presents "Microbes and us," discussing the human microbiome's role in poorly understood conditions like idiopathic malodor and multiple chemical sensitivities (MCS). Previously, MEBO interviewed Metametrix about their GI Effects panel, which measured stool bacteria, fungus, and parasites with DNA analysis.  Metametrix, pioneer in diagnostics of nutritional insufficiencies and metabolic dysfunction,was later acquired by Genova Diagnostics.

Dr. Nigel Manning introduces 12 potential subtypes of TMAU. Out of 1,150 urine samples from 716 individuals collected between 1997 and 2009, 379 (53%) indicate significant TMAU presence. The launch of a new FMO3 genetic testing service promises to provide clearer diagnostic results. Additionally, a TMAU service dog program is initiated.

2011: The Advent of Genomic Data Sharing

Community members begin sharing genomic data, and MEBO critiques the limitations of 23andMe's FMO3 testing in blog posts. Dr. George Preti and his team at the Monell Center publish "Individuals reporting idiopathic malodor production: demographics and incidence of trimethylaminuria", revealing that only one-third of individuals with idiopathic malodor test positive for TMAU. New study from Oxford, proposes two genes coding enzymes, besides FMO3, NAT8 and PYROXD2, both with relatively uncharacterized functional roles, as potentially linked to TMAU. 

The second annual meetup in Washington, DC, focuses on the interplay between genetic mechanisms and holistic health. Skype conference call group is formed. 

2012: Empowering Patients Through Technology

A new MEBO study focusing on alveolar breath is initiated (NCT03451994). Aurametrix health management software is publicly launched, allowing patients to diagnose metabolic inefficiencies through digital food and symptom journaling. Karen James, MEBO UK’s Public Relations Director, publishes an article in the Royal College of General Practitioners (RCGP) journal InnovAiT, describing the life of a TMAU sufferer. For iGEM competition,  student team from Fatih university genetically engineers bacteria producing geraniol and FMO3 to eliminate TMA odors. Their product, FreshEcoli, is supposed to work as a synthetic perfume. 

The Third Annual Meetup in Miami Beach features Dr. Elizabeth Shephard discussing pharmacogenetics and personalized medicine.

2013: Deepening Theoretical Insights

MEBO UK's scientific director, Dr. Colin Harvey-Woodworth, publishes an article proposing that some MEBO symptoms may be secondary to dimethylsulphidemia, a previously unidentified metabolic condition linked to DMGDH gene (missense mutation in DMGDH was known to be associated with fish odor similar to pyridoxine non-responsive homocystinuria). Concurrently, a mediterranean study reveals that individuals carrying FMO3 mutations may not necessarily experience odor issues. The study finds that the TMA/TMAO ratio in urine samples from individuals with 158KK/308EG variants indicates reduced FMO3 activity, yet these individuals do not exhibit the hallmark fish-like odor commonly associated with trimethylaminuria. This data underscores the notion that the expression of trimethylaminuria symptoms is influenced by factors beyond the presence of specific genetic variants.

2014: Therapeutic Innovations

Dr. Jean-François Brugère proposes the therapeutic use of archaea to prevent trimethylaminuria and cardiovascular disease. The technique was patented but not yet tested in humans. MEBO's TMAU urine testing program is initiated, and the results  are discussed. Another student team from Paris University, genetically engineers skin bacteria by introducing a trimethylamine mono-oxygenase from a non-human bacteria Ruegeria pomeroyi, for iGEM competition. Dr. Aydin proposes new definitions for halitosis. Reddit TMAU and PATM groups are created. 

2015: Expanding Testing and new molecular targets

The MEBO Conference in Orlando distributes urine test kits based on choline challenges and discusses emerging trends in testing methodologies.

3,3-Dimethyl-1-butanol (DMB), which is a structural analog of choline found in some foods, such as balsamic vinegars, red wines, some cold-pressed extra virgin olive oils and grapeseed oils is demonstrated to inhibit TMA production by gut bacteria. DMB has potential as a therapeutic approach. Studies also show the inhibitory effects of Resveratrol on TMA production in mice, further expanding the scope of potential small molecule targets. Dr Stanley Hazen files a patent.

2016: Streamlining Diagnostic Approaches

MEBO collaborates with Professor David Wishart on a Urine Metabolomics study, registered as NCT02683876, involving Canadian participants. The study aims to explore simpler, non-challenge-based tests for diagnosis.

Several sufferers in the MEBO community report taking Resveratrol for a few months, with excellent results in decreasing or completely eliminating their odor symptoms while increasing consumption of foods high in choline, carnitine, and lecithin.

2017: Diagnostic Breakthroughs and the Social Media Shift

MEBO's Scientific Director, Irene Gabashvili, publishes the Biolab study on BiorXiv. The study reveals significant differences in intestinal permeability among participants based on body regions responsible for VOC emissions. In addition, the study identifies two subgroups of MEBO/PATM sufferers based on sugar intake. Due to the small sample size of 16 participants, the article remains a preprint. Unfortunately, the current structure and incentives of mainstream academic publishing favor well-funded research on common diseases and are less accommodating to research on overlooked rare conditions. 

A Monell Center Study published in BMC Medical Genetics delves into the genetic complexities of TMAU, revealing that not all cases are linked to the FMO3 gene. Although the choline challenge test confirmed a diagnosis of TMAU by revealing a high level of urinary TMA in all 10 subjects, genetic analyses revealed that the FMO3 gene appeared to be normal in four of the 10. Additional analyses revealed defects in several other genes that could contribute to the inability to metabolize the odorous TMA. No rare variants are found in PYROXD2 and a DMGDH, but there were associations with BHMT2, SARDH and SHMT1 genes, which directly interact with DMGDH in the gene network and may participate in the same pathway. At MEBO conference in Miami Beach, Professor Shephard talks about microbiome and diet. 

Armpit microbiome transplantation shows reduction in odor when performed from one sibling to another. 

Danny Kunz and his Citizen Research Group in Germany initiate a DNA sequencing study. Their simulations backed by large enzyme databases suggest that Thyroid-stimulating hormone (TSH) may play a role. Danny proposes a new name for the condition: Intestinal Metabolic Bromhidrosis Syndrome (IMBS).

TMAU UP Podcast is launched on YouTube. Facebook's "Groups" feature spurs the creation of new private MEBO and PATM communities, marking a new era in community engagement and data sharing.

2018-2020: Advancing Research and Understanding

A Microbiome study of MEBO and PATM communities is initiated, registered as NCT02683876. 

A Japanese paper confirms PATM as a physical condition connected to skin petrochemicals and microbes. Meanwhile a case report entitled "People allergic to me and body dysmorphic disorder" published in Asian Journal of Psychiatry is linking a case to a relatively common psychiatric disorder characterized by preoccupations with perceived defects in physical appearance. The average age of BDD onset was previously estimated as 15 with symptoms lasting 18 years on average without proper treatment. The prevalence of BDD is thought to be 0.7-2.4% in the general population, but the condition remains underdiagnosed and poorly understood.

Results from the MEBO-Wishart study align with previous MEBO/PATM findings but highlight the limitations of morning urine tests. A new PATM survey is conducted by an independent PATM ufferer/researcher. Average age of responders is 28. Mononucleosis due to CMV is proposed as the cause of PATM.

A UC San Diego student team explores the enzymatic breakdown of TMA. New gene SELENBP1 is proposed to explain metabolic halitosis. A patent on using Mikania plant extract to inhibit the conversion of choline to trimethylamine (TMA) is filed and granted, based on an earlier patent for using this plant to suppress body odor. 

RareConnect is established as a platform for those affected by rare diseases, including MEBO Research members. MEBO Research becomes a member. Unfortunately, by the end of 2023 it will be shut down, not being able to compete with Facebook and Reddit. Yahoo Groups shut down on December 15, 2020, for the same reason. New Instagram and WhatsApp groups are created.

New paper "Treatments of trimethylaminuria: where we are and where we might be heading" is published. It reviews Fecal microbial transplantation (FMT) that was not especially successful for reducing TMA or was only transiently effective as the symptoms returned one year after treatment. Antibiotic treatment is also transiently effective in some patients and completely ineffective in others.  Future research directions include gene therapy, enzyme replacement/enhancement therapy and gut microbiome modulation. 

Peer-reviewed paper examining the microbiome traits of individuals self-identifying with PATM and MEBO (NCT02683876) is published in JMIR Dermatology. The study reveals that both MEBO and PATM share increased levels of malodor-associated skin bacteria compared to non-MEBO/non-PATM groups, correlating with severity of self-reported symptoms. However, both populations exhibit significant heterogeneity.

2021-2023: Ongoing Challenges and Future Directions

A COVID study identifies flare-ups in 10-15% of the MEBO population post-infection and vaccination, possibly related to microbiome and hormonal fluctuations (NCT04832932; peer-reviewed paper published in JMIR Formative Research). COVID-19 has led to the emergence of new cases, with individuals developing MEBO/PATM conditions following infection and/or vaccination.

A cysteine challenge test for hydrogen sulfide production is suggested. Florida State University's iGem team proposes a synthetic biology project for TMAU. 

New paper by Chris Callewaert explores various cutting-edge approaches to skin health, including genetically engineered probiotics and microbiome transplantation. While promising, the latter method currently lacks scalability for industrial applications. The paper also delves into skin bacteriotherapy, a technique involving the application of one or multiple pure bacterial cultures with health-promoting properties to cleansed or disinfected skin areas. Additionally, the study examines the use of prebiotics applied directly to the skin to encourage the growth of beneficial microbes. Each of these innovative approaches holds promise but also presents its own set of challenges.

A study by Professor Sekine in Nature Scientific Reports identifies volatile organic compounds as key differentiators between PATM sufferers and controls. These results align with our yet to be published findings from MEBO-Menssana Alveolar Breath Test Study (NCT03451994) and Microbiome study (NCT03582826). 

The FSU team introduces their innovative probiotic, E.esperance, at the iGEM competition in Paris on November 2, 2023.

Despite these advancements, mainstream science remains largely uninterested in community-based research, leaving MEBO, PATM and TMAU without a definitive cure.

Human Skin Gas Profiles in PATM

People Allergic to Me (PATM) is a perplexing condition that has left both sufferers and medical professionals searching for answers. Thousands of individuals worldwide claim to experience PATM, leading to severe mental health challenges such as depression, anxiety, and suicidal tendencies. Despite its far-reaching impact, the underlying causes remain mysterious, with only a few scientific studies dedicated to understanding this condition. While a small subset of PATM sufferers has been diagnosed with TMAU, the majority remain without a diagnosis. 

A new study lead by Professor Sekine, recently published in Nature Scientific Reports, explores the human skin gas profiles to shed new light on PATM. 

The study included 44 subjects, divided into two groups: 24 without PATM (non-PATM) and 20 with PATM. The non-PATM group involved 13 male and 11 female participants (age: 18–59, 31 ± 13 years old). The PATM group comprised 12 male and 8 female participants (age: 19–53, average 39 ± 12 years old).

The non-PATM group had no known diseases, while the PATM group reported symptoms of PATM without other apparent diseases.

Researchers sought to understand the skin gas profile of people with and without PATM, potentially the source of body odor or other types of emissions. They measured the emission rate of 75 volatile compounds from the skin using a tool called a passive flux sampler (PFS) coupled with gas chromatography/mass spectrometry (GC/MS). PFS was designed to be convenient and unobtrusive, allowing people to use it on the go without any hassle.

Participants in the study were given a PFS device, similar in size to a bottle cap, to collect skin gas samples from their non-dominant forearm. They wore this device for an hour without any restrictions on their activities. The device was easily attached to the skin with a piece of surgical tape and didn't require any special preparation. After collecting the samples, PFS devices were sent to the laboratory and analyzed.

The PATM group exhibited significantly greater emission fluxes for a variety of chemicals, including some with offensive odors, and lower emissions of others, including some with more pleasant or neutralizing smells. 

Among the 75 measured skin gases, the PATM group exhibited significantly greater emission fluxes for chemicals like alcohol 2-ethyl-1-hexanol (2E1H), aldehyde isovaleraldehyde, hexanal, acetone, toluene, m,p-xylene, methyl mercaptan, ethyl mercaptan, and allyl methyl sulphide (AMS). These chemicals often have offensive odors and/or can lead to adverse health effects. The emissions of petrochemical 2E1H, and aromatic hydrocarbons (with benzene ring in their structure): toluene, and m,p-xylene were notably higher in the PATM group, with increases of approximately 12, 39, and four times, respectively.

Volatile organosulfur compounds such as methyl mercaptan (fecal odor, resembling smell of rotten cabbage or decaying vegetables), ethyl mercaptan (rotten fish, garlic, or onions), and Allyl Methyl Sulfide (AMS, garlic- or onion-like odor) were also significant. These compounds have extremely low odor thresholds and could easily alter body odor perception in PATM subjects. Bacteria in the oral cavity, such as Porphyromonas gingivalis and Anaerobic bacteria in the gut, such as Desulfovibrio species are producers of Methanethiol. 

Isovaleraldehyde contributes to body odor with a pungent fruit-like smell that can also contribute to aroma of beer and cheese. It can be sourced from metabolic breakdown of amino acids like leucine and valine, hence dietary intake, and microbial activity in the gut by methylotrophic yeasts. , species of Clostridium, Actinobacteria (Rhodococcus, Mycobacterium and Gordonia), Proteobacteria (Acetobacterium such as Gluconobacter oxydans), Odoribacteraceae, Ruminococcus gnavus, etc. These microbes are capable of producing  Isovaleraldehyde through anaerobic fermentation and the mevalonate-independent glyceraldehyde 3-phosphate/pyruvate pathway. 

Greater emission of acetone might indicate eating disorders in the PATM group, as it is influenced by fasting, starvation, or diet.

The PATM group had less skin release of various substances, including some types of alcohols, smell-related chemicals, and fruity-smelling compounds. Some of these chemicals are used in flavors or fragrances and are known to have a relaxing effect.

For example, α-pinene, β-pinene, and D-limonene have antifungal activities as well as abilities to decrease depression-like behavior and improve memory via an anti-neuroinflammatory mechanism under chronic restraint stress. 

D-limonene can be consumed through the diet by eating citrus fruits or drinking citrus-flavored beverages. Some fruity-smelling compounds are naturally found in fruits like peach and pineapple and contribute to sweet body scents. It can also be absorbed through the skin from personal care products containing citrus oils or inhaled from air.

Acetic acid smells like vinegar and is made by bacteria breaking down certain substances in sweat. It is linked to body odor in young adults. Lower skin emissions of acetic acid in the PATM group showed that sweating may not be the cause of their unique body odor. Acetic Acid is produced by acetic acid bacteria, such as Acetobacter and Gluconobacter species. Certain lactic acid bacteria, such as Lactobacillus, can also produce acetic acid.

The study also looked at benzaldehyde, which might come from toluene. People with PATM had much more skin emission of toluene but less of benzaldehyde.

The presence of benzaldehyde in the human body is typically at low levels, and its occurrence may vary based on factors such as diet, environmental exposure, individual metabolism, and gut microbiome composition. Almonds, apricots, and cherries are examples of foods that contain benzaldehyde or related compounds. Toluene is a common solvent used in various industrial and household products such as paints, glues, nail polish, and cleaning agents. Inhalation of fumes from these products can lead to toluene being present in the blood and tissues.

The ratio of toluene to benzaldehyde was much higher in the PATM group, and this ratio is seen as a key sign of PATM.

Air quality in terms of petrochemicals is worse in urban areas, high traffic areas, industrial workspaces, poorly ventilated interiors, newly constructed or renovated spaces, automotive interiors, salons and beauty parlors, households using cleaning products containing petrochemicals, such as certain detergents, aerosol sprays, and solvents, spaces with indoor smoking and even some healthcare facilities. 

Our previous study on breath VOC profiles in PATM, TMAU and MEBO (Alveolar Breath Test Study registered as NCT03451994) has unveiled intriguing insights into petrochemical metabolism, indicating that non-TMAU MEBO population may have difficulties with metabolizing environmental pollutants, while the Microbiome study (registered as NCT03582826) uncovered possible microbial sources of compounds that differentiate PATM, TMAU and MEBO from non-MEBO & non-PATM populations. Our findings align remarkably with Professor Sekine's work.

The synergy between these discoveries is shedding light on the underlying mechanisms and potential diagnostic markers. We will be publishing these complementary results soon, further contributing to the scientific community's knowledge of PATM, TMAU and MEBO.

Stay tuned for our upcoming publications, as we continue to unravel the mysteries of these conditions, working towards a future where this condition is better understood, diagnosed, and managed. 

REFERENCES

Sekine Y, Oikawa D, Todaka M. Human skin gas profile of individuals with the people allergic to me phenomenon. Sci Rep. 2023 Jun 10;13(1):9471. doi: 10.1038/s41598-023-36615-1. PMID: 37301918; PMCID: PMC10257688.

Lactobacillus, Bifidobacterium and other emerging probiotics

In the past few decades, Lactobacillus and Bifidobacterium genera were the main bacteria to be used as probiotics. One of the reasons for such attention was that these bacteria have the ability to thrive aerobically and are simple to package for sale. Cass Nelson-Dooley and Tony Hoffman of Metametrix (acquired by Genova Diagnostics in 2012) talked about these probiotics in MEBO interviews in 2009, emphasizing that high levels of Lactobacillus could be bad in some cases. Diets rich in simple carbs, poor absorption and small intestinal pockets can feed and trap excess Lactobacillus. Adding probiotics Bifidobacteria or Saccharomyces boulardii and prebiotic fiber to the diet could, in their opinion, help the MEBO population. D-lactate was one of the tests they offered that measured the level of this byproduct of bacterial fermentation, indicating an overgrowth of bacteria in the small intestine. According to our early clinical studies, D-lactate, however, was elevated in less than 20% of MEBO and PATM populations. 

Even though Lactobacillus is only a minor member of the human colonic microbiota, the proportions of those bacteria and particular strains are frequently either positively or negatively correlated with human disease and chronic conditions. Although it generally is not considered a pathogen, it can cause disease in compromised hosts, including bacterial endocarditis, pleuropulmonary infections, gastrointestinal abscesses, urinary tract infection, conjunctivitis, dental caries, and endometritis. Lactobacillus bacteremia, presumably secondary to bacterial translocation from the gastrointestinal tract, has been reported in a patient with severe intestinal inflammation caused by ulcerative colitis. A decrease in genus Faecalibacterium and increase in Lactobacillaceae has been previously reported in patients with constipation (Lactiplantibacillus plantarum P9 supplementation, on the other hand, helped to increase frequency of bowel movements, while L11 improved gut health and odor in cats). Compared to healthy individuals, pediatric and adult Crohn's disease (CD) patients had an increased relative abundance of Lactobacillus species. In both cases, Lactobacillus enrichment coincided with depletion of F. prausnitzii - that could represent a good candidate as next-generation probiotic. Another study found that Weissella cibaria ZWC030 can inhibit skatole. 

The percentages of Bifidobacterium and the Lactobacillus group presented a decreasing trend in patients with quiescent ulcerative colitis (UC) compared to active UC, although no significant differences were observed. Excessive amounts of Bifidobacteria can have negative effects on the body, such as in the case of Bifidobacterium breve bacteremia caused by excessive probiotic supplementation in infants with gastrointestinal conditions. On the other hand, Lactobacillus, Bifidobacterium and F. prausnitzii are depleted in IBS patients, resulting in lower SCFA concentrations (short-chain fatty acids, which are organic acids produced by gut bacteria during fermentation of indigestible foods) compared with healthy individuals. Maternal prenatal stress could also cause lower levels of Lactobacillus and Bifidobacterium and keep them low even later in life. With lower levels of Bifidobacterium, celiac patients have an imbalance in the intestinal microbiota, regardless of pH, even while on a gluten-free diet. Hormone treatment affects Bifidobacterium longum's ability to produce acids: progesterone reduces lactic acid and acetic acid production, while estradiol and thyroxine increase levels of both lactic acid and acetic acid (ethinyl estradiol) or lactic acid and butyric acid (thyroxine hormone). 

Data from our microbiome study (NCT03582826: Microbial Basis of Systemic Malodor and "People Allergic To Me" Conditions  - ClinicalTrials.gov) show that while there was a general trend of increasing levels of Bifidobacteria and Lactobacillus in individuals who achieve remission, less than 10% of participants needed to boost levels of both species to improve their condition. In line with previous knowledge, in MEBO/PATM population, Bifidobacteria (one of the first microbes to colonize the human gastrointestinal tract) was more common in younger individuals. About one third of the participants experienced lesser symptoms when increasing levels of their gut Bifidobacteria, another third benefited from more Lactobacillus and the remaining third felt better when increasing levels of Faecalibacterium prausnitzii (a butyrate-producing anaerobe typically associated with good health). Changes in the levels of these bacteria corresponding to recovering are overlayed on Figure 5 from our paper published in JMIR dermatology. It was illustrating changes in microbial diversity vs abundances of selected bacterial species associated with odor (CSS) for 12 female (F1-F12) and 10 male (M1-M19) participants who self-reported both flare-ups (beginning of the arrow) and improvements (end of the arrow). We added text boxes showing whether the levels of F. prausnitzii (F), Bifidobacterium (B) and Lactobacillus (L) are increasing (🡹) , decreasing (🡻) or fluctuating (🡺) as symptoms resolve. It is obvious that individuals with the highest bacterial diversity don't benefit from increasing levels of probiotic diversity, while those with low diversity levels do need more probiotic microbes in their system. The figure demonstrates the complexity of these bacterial perturbations and emphasizes the need to consider more than just three species when predicting which treatment will work best for reducing MEBO and PATM symptoms. 

As we mentioned in the previous blog post, Lactobacillus is the main genera responsible for odors of the uncooked food waste and off-flavor pit mud.  Some strains of Lactobacillus produce lactic acid, which can contribute to a more acidic environment in the gut. This can be beneficial for some people, but for others it can exacerbate odor issues. Bifidobacteria could also produce organic acids such as acetic acid and lactic acid in addition to short-chain fatty acids (SCFAs) like butyrate, which can have anti-inflammatory effects and promote gut health, but some people may find it unpleasantly smelling. F. prausnitzii produces a range of metabolites including one of the worst smelling compounds Putrescine. F. prausnitzii  plays important role in balancing immunity. Its butyrate production has been correlated to the capacity to induce IL-10, an anti-inflammatory cytokine, in peripheral blood mononuclear cells (PBMC) but not to the ability to block IL-8 secretion in TNF-α-stimulated HT-29 cells. In COVID-19, Faecalibacterium prausnitzii has been inversely correlated with disease severity. 

Research has shown that the gut microbiome is far more complex than previously thought, with hundreds of bacterial species interacting in a delicate balance.  Therefore, focusing solely on Lactobacillus and Bifidobacterium, or any other bacterium, may not be enough to promote a healthy gut microbiome for everyone. Besides, different strains of bacteria within the same species can have different effects on the body.

After more than a century of research, the following species are identified as the primary probiotic species of Lactobacillus species: L.acidophilus, L.casei, L.fermentum, L.gasseri, L.johnsonii, L.paracasei, L. plantarum, L. rhamnosus, and L. salivarius. For Bifidobacteria these are: B.adolescentis, B.animalis, B.bifidum, B.breve, and B.longum. We are learning more about strains of these species. Novel probiotic strain Bifidobacterium bifidum CECT 7366 is active against the pathogenic bacterium Helicobacter pylori - and so are variations of Saccharomyces Boulardii and Lactobacilli johnsonii. Another strain L. plantarum 299v can directly interfere with E. coli colonization and improve the immunological status of the intestinal mucosa although these results have not yet been confirmed in humans. Lactobacillus GR-1 and B-54 or RC-14 strains in the vagina has been shown to reduce the risk of urinary tract infections. Mileti et al. found that Lactobacillus paracasei displayed a delay in the development of colitis and a decreased severity of disease but that L. plantarum and L. rhamnosus GG exacerbated the development of dextran sodium sulfate (DSS)-induced colitis. 

L. rhamnosus supplementation contributes to higher intestinal absorption of free choline and elevated production of methylamines including TMA, whereas L. paracasei consumption may result in increasing bacterial consumption of choline for cholesterol assimilation and phospholipid metabolism rather than for methylamine metabolism.

Bifidobacterium supplemented with various fiber additives can prevent the growth of Clostridium difficile, while Lactobacillus salivarius protects the broiler chicks from Salmonella infections. Several strains of other species promising as probiotics are from Roseburia spp., Akkermansia spp., and Faecalibacterium spp. Probiotic potential risk score (PPRS) allowed to classify 84 Faecalibacterium prausnitzii strains  into low-, medium-, and high-risk groups. 15 strains identified as low-risk strains are prioritized for clinical application. 

Unfortunately, the extreme oxygen sensitivity of F. prausnitzii imposes practical challenges to the production, transportation, storage, and manufacturing of probiotic products to be evaluated in a clinical setting. Instead, we have to turn to prebiotics - a type of dietary fiber - in our food . F. prausnitzii's growth is promoted by inulin, inositol (vitamin B8) and fructo-oligosaccharides, chicory roots, wheat, onion, banana, garlic, and leek, wheat, rye, rice, barley, oat, and sorghum, and gold kiwifruit. 

Gut microbiota can be also influenced by phytochemicals. In one study, black raspberry (BR) reduced the serum levels of trimethylamine-N-oxide and cholesterol in rats fed excessive choline with a high-fat diet (HFC). The authors hypothesized that since gut microbiota plays a crucial role in the production of trimethylamine and microbial metabolites, BR could influence gut microbial composition. Their study examined microbiomes and metabolomes of rats and showed that the BR supplementation enriched Bifidobacterium and reduced Clostridium cluster XIVa. 

While we have made significant progress in understanding the role of probiotics and prebiotics in supporting our gut health, it's important to recognize that there is still a great deal that we don't know. It's becoming increasingly clear that a personalized approach to prebiotic and probiotic use may be necessary to achieve optimal health outcomes. This approach involves paying attention to how different foods make you feel and adjusting your diet accordingly, while eating a diverse and balanced diet that incorporates a variety of whole foods and phytochemicals, staying hydrated, getting enough sleep and exercise, and managing stress levels. Focusing on overall health and well-being will help to support the body's natural ability to maintain a healthy microbiome and avoid dysbiosis-related health issues.

REFERENCES

Din AU, Hassan A, Zhu Y, Yin T, Gregersen H, Wang G. Amelioration of TMAO through probiotics and its potential role in atherosclerosis. Applied Microbiology and Biotechnology. 2019 Dec;103:9217-28.

Pacifico L, Osborn JF, Bonci E, Romaggioli S, Baldini R, Chiesa C. Probiotics for the treatment of Helicobacter pylori infection in children. World J Gastroenterol 2014; 20(3): 673-683 [PMID: 24574741 DOI: 10.3748/wjg.v20.i3.673] 

Lim T, Lee K, Kim RH, Ryu J, Cha KH, Park SY, Koo SY, Hwang KT. Effects of black raspberry extract on gut microbiota, microbial metabolites, and expressions of the genes involved in cholesterol and bile acid metabolisms in rats fed excessive choline with a high-fat diet. Food Sci Biotechnol. 2023 Feb 13;32(4):577-587. doi: 10.1007/s10068-023-01267-4. PMID: 36911337; PMCID: PMC9992478.

Heeney DD, Gareau MG, Marco ML. Intestinal Lactobacillus in health and disease, a driver or just along for the ride?. Current opinion in biotechnology. 2018 Feb 1;49:140-7.

Martín R, Miquel S, Benevides L, Bridonneau C, Robert V, Hudault S, Chain F, Berteau O, Azevedo V, Chatel JM, Sokol H. Functional characterization of novel Faecalibacterium prausnitzii strains isolated from healthy volunteers: a step forward in the use of F. prausnitzii as a next-generation probiotic. Frontiers in microbiology. 2017 Jun 30;8:1226.

Nalbandian A, Sehgal K, Gupta A, Madhavan MV, McGroder C, Stevens JS, Cook JR, Nordvig AS, Shalev D, Sehrawat TS, Ahluwalia N. Post-acute COVID-19 syndrome. Nature medicine. 2021 Apr;27(4):601-15.

Bai Z, Zhang N, Jin Y, Chen L, Mao Y, Sun L, Fang F, Liu Y, Han M, Li G. Comprehensive analysis of 84 Faecalibacterium prausnitzii strains uncovers their genetic diversity, functional characteristics, and potential risks. Frontiers in Cellular and Infection Microbiology. 2023 Jan 4;12:1924.

Gabashvili I.S. Cutaneous Bacteria in the Gut Microbiome as Biomarkers of Systemic Malodor and People Are Allergic to Me (PATM) Conditions: Insights From a Virtually Conducted Clinical Trial. JMIR Dermatol 2020;3(1):e10508 URL: https://derma.jmir.org/2020/1/e10508 DOI: 10.2196/10508

Rašić, J.L., Vujičić, I.F., Škrinjar, M. et al. Assimilation of cholesterol by some cultures of lactic acid bacteria and bifidobacteria. Biotechnol Lett 14, 39–44 (1992). https://doi.org/10.1007/BF01030911