Pancreatic cancer is very deadly, with low survival rates, largely attributed to the fact that it does not present clearly with symptoms until it has reached a more serious stage (Kamisawa et al., 2016). In fact, out of the top 10 cancer-related deaths, pancreatic cancer is ranked number 7 (Khalaf et al., 2021). The pancreas is located near the liver, spleen, and gallbladder; within the abdomen (Fig. 1 Cleveland clinic diagram). It aids in digestion as well as the release of certain hormones. Pancreatic tumors can grow and obstruct the path of bile through the common duct, resulting in jaundice (Puckett, 2024), therefore not only interfering with the aforementioned pancreatic functions, but those of the organs around it. According to the Mayo Clinic, some common symptoms of pancreatic cancer include weight loss, jaundice, back pain, and blood clots.
Figure 1. Infographic about social anxiety. Graphic from zoelife, 2024.
Introduction:
Ever wonder how much of an impact your gut microbiome really makes on everyday life? New research suggests your microbiome can affect your physical and emotional well being, including levels of social anxiety. “The gut microbiota shows compositional alterations in a variety of psychiatric disorders including depression, generalized anxiety disorder (GAD), autism spectrum disorder (ASD) and schizophrenia but studies investigating the gut microbiome in social anxiety disorder (SAD) are very limited” (Butler, 2023).Therefore researchers took it upon themselves to study the effects of our microbiome on social anxiety disorder. Social anxiety disorder has become one of the most common psychiatric conditions with rates as high as 13% (Butler, 2023). The current treatments for SAD are not always effective, “the use of psychosocial/psychotherapeutic approaches declines gradually from initiation of treatment over the course of 8 years” (Keller, 2003). This has encouraged researchers to look at alternative treatments which ultimately led them to dive deeper into our gut-brain axis. “It is broadly recognized that the gut and brain are in constant bidirectional communication, of which gut microbiota and its metabolic production are a major component, and form the so-called gut microbiome–brain axis” (Sasso, 2023). With this information they hope to be able to predict and treat SAD through understanding the microbes at play.
Figure 2. Infographic showing the microbiome-gut-brain axis. Graphical abstract from Sasso, 2020.
SAD has become one of the most common psychiatric conditions with rates increasing globally (Keller, 2003). The disorder is associated with symptoms of marked fear or anxiety about one or more social situations where an individual is exposed to possible scrutiny by others. SAD can be a chronic disorder that reduces the quality of life drastically. This disorder is diagnosed through trained professionals in psychology and can be treated with medication. “Current first-line treatments include selective serotonin reuptake inhibitors (SSRIs), serotonin and norepinephrine reuptake inhibitors (SNRIs) and cognitive behavioral therapy. Unfortunately, a significant proportion of patients fail to adequately respond to first-line pharmacotherapy” (Butler, 2023). With the limited success of current first line treatments researchers look to examine the microbiome-gut-brain (MGB) axis for answers.
The human microbiome is uniquely different from individual to individual. Microbes are everywhere including inside us, trillions of microorganisms colonizing our body is what makes up our microbiome and the microbes living specifically in our gut make up our gut microbiome (Sasso, 2023). These microorganisms are predominantly bacteria but can be viruses, protozoa, fungi and archaea. The gut microbiome in particular can exceed over 100 times the amount of the human genome in the body (Sasso, 2023). This gives the gut microbiome a huge genetic potential which no doubt can affect our daily processes. Since the push to discover more about gut microbiome, scientists have been able to link it to many health concerns including autoimmune, metabolic and neurological conditions. This includes everyday health concerns like allergies, celiac disease or anxiety can be linked to the composition of our gut microbiome. With how much genetic potential the gut microbiome can possess, it’s an understandable conclusion to predict that it could also play a role in social anxiety disorder.
Central Question:
Scientist (Butler, 2023), researching “The gut microbiome in social anxiety disorder: evidence of altered composition and function” analyzed the genetic makeup of fecal samples for compositional and functional differences in the gut microbiome of patients with SAD in comparison to health patients to determine whether the gut microbiome is a factor in SAD. Their main goal was to answer: does the gut microbiome really play a role in SAD?
Evidence:
This question was researched through patients who had obtained a clinical diagnosis of SAD and were between the ages of 18-65 years old. Only patients who were not taking any medication that could interfere or didn’t have acute or chronic medical illness were included. Patients taking psychiatric medications that were not predicted to influence the outcome were able to maintain that protocol. Scientists then kept track of their food frequency and intake through a questionnaire, the stool consistency, exercise levels and sleep. Fecal samples were collected from the participants and the genetic data of the microbes were processed. The study used 31 patients with SAD and 18 healthy patients as controls.
For the first time this study found that the gut microbiome is genetically different in people with social anxiety disorder (SAD) than that of healthy people. “Beta diversity, an indicator of overall microbiota composition, was significantly different between the two groups. The relative abundance of three genera, Anaeromassilibacillus, Gordonibacter and Parasutterella, and two corresponding species, Anaeromassilibacillus sp An250 and Parasutterella excrementihominis differed significantly between SAD patients and controls” (Butler, 2023). This adds to growing evidence that our social brain function and microbiome may be linked. The change in genus of the gut microbiome was significantly different between the two groups. Anaeromassilibacillus so An250 which was found in almost half the SAD patients but only one of the healthy controls. This genus is newly discovered and is also found increased in the gut of patients with autism spectrum disorder, depression and schizophrenia. This bacteria is part of the Clostridiales taxa which is a group of bacteria, the increase in Clostridiales seem to be associated with psychiatric disorder showing there may be a link to social behavior. Anaeromassilibacillus is a new addition to the human microbiome database so there is still limited research on how it affects human health.
It is hard to determine how important the difference in specific bacteria in the patient group is. This is because our gut microbiome is constantly interacting with one another and the host. Much more research is needed to fully characterize the microbial community structures and gain insights into how they influence the human host, however this study demonstrated a clear difference in microbial composition between the healthy patients and those suffering from social anxiety disorder. However a link in gut microbiome and the microbiome-gut-brain axis is yet to be fully understood.
Figure 3. Genus-level differences in relative abundance between SAD and controls seen in three genera; Anaeromassillibacillus and Gordonibacter are enriched in SAD while Parasutterella is enriched in healthy controls. B Species-level differences in relative abundance between SAD and controls; Anaeromassilibacillus sp An250 is increased in SAD while Parasuterella excrementihominis is enriched in healthy controls. (*p = <0.05) (Clr centred log-ratio transformed, HC Healthy Control, SAD Social Anxiety Disorder). Data figure from Butler, 2023.
My Questions:
More research is certainly needed to fully understand how the microbiome-gut-brain axis is influenced and what specific bacteria play the biggest roles. My question is wether or not psychotropic medication impact the gut microbiome. I would like to see this further studied to determine if there was a link between the psychotropic medications and microbiome some of the patients were taking to see if that can also explain the difference in gut microbiome composition.
Further reading:
To read the initial scientific research article that looked at the effects of the human microbiome of social anxiety disorder check the link below.
Read the article below to learn more about the microbiome-gut-brain axis. This article explains how it works and the value of researching the interactions between our gut microbiome and brain.
Butler, M. M., Bastiaanssen, T. F. S., Long-Smith, C., et al. (2023). The gut microbiome in social anxiety disorder: Evidence of altered composition and function. Translational Psychiatry, 13, 95. https://doi.org/10.1038/s41398-023-02325-5
Sasso, J. M., Ammar, R. M., Tenchov, R., Lemmel, S., Kelber, O., Grieswelle, M., & Zhou, Q. A. (2023). Gut microbiome-brain alliance: A landscape view into mental and gastrointestinal health and disorders. ACS Chemical Neuroscience, 14(10), 1717–1763. https://doi.org/10.1021/acschemneuro.3c00127
Xiong, R. G., Li, J., Cheng, J., Zhou, D. D., Wu, S. X., Huang, S. Y., Saimaiti, A., Yang, Z. J., Gan, R. Y., & Li, H. B. (2023). The role of gut microbiota in anxiety, depression, and other mental disorders as well as the protective effects of dietary components. Nutrients, 15(14), 3258. https://doi.org/10.3390/nu15143258
Zhou, X., Shen, X., Johnson, J. S., Spakowicz, D. J., Agnello, M., Zhou, W., Avina, M., Honkala, A., Chleilat, F., Chen, S. J., Cha, K., Leopold, S., Zhu, C., Chen, L., Lyu, L., Hornburg, D., Wu, S., Zhang, X., Jiang, C., Jiang, L., … Snyder, M. P. (2024). Longitudinal profiling of the microbiome at four body sites reveals core stability and individualized dynamics during health and disease. Cell Host & Microbe, 32(4), 506–526.e9. https://doi.org/10.1016/j.chom.2024.02.012
If you’ve ever met a set of identical twins, your initial impressions are likely about their similarities. Their height, facial features, and sometimes their mannerisms look like a reflection of the other. Visual similarities in identical twins can be traced back to genetics. When two people share the exact same set of DNA, their genes encode the same physical characteristics. But take a closer look, and you might notice that twins are not exactly the same. For example, their weight and skin texture may be different. One might develop a disease like cancer that the other never will. This discrepancy can be explained by environmental factors. Environment plays a huge role in shaping a person’s life. It can even affect how somebody’s genes work without ever changing their DNA (Peixoto et. al 2020). The study of the environment’s effect on genes is called epigenetics. Epigenetic changes can be passed down from parent to child (Geraghty et. al 2016).
The first few months of an infant’s life are very important for the development of the gut microbiota, which shapes immune responses, metabolic function, and overall health. The gut microbiota is a complex community of tiny microbes that inhabit your digestive system, namely the large intestine. Early colonization of the gut can change based on factors like how a baby was born (vaginal vs cesarean section), what they eat (breastfeeding vs formula) and healthcare treatments (antibiotic use). Disruptions to this delicate balance during infancy can have long-term consequences like increasing the risk for certain conditions like allergies, obesity and gastrointestinal disorders later in life (Lagouvardos, 2022, p.334).
Given the deep connection between the gut microbiota and health, scientists are looking into how different decisions during infancy can shape these microbial communities. One of these decisions is the use of synbiotics. Synbiotics are a combination of probiotics (live beneficial bacteria) and prebiotics ( food for bacteria). Synbiotic formulas, which blend probiotcs and prebiotics, are made to copy the benefits of breastfeeding and support the development of a healthy gut microbiome in infants who are not breastfed. Synbiotic formulas are common but are, not surprisingly, more expensive than their non-synbiotic formula counterparts.
The industrialization of the food industry has undergone a dramatic transformation in recent years. The average western consumer now consumes more ultra-processed food than ever before, shifting away from more seasonal and traditional diets. This change is being fueled by the advancement in marketing techniques, which shows over 50 percent of all food and beverage advertisements are processed foods (Zhang et al. 2022), and making ultra-processed food more readily available and appealing. However, this convenience comes at a cost: rising rates of obesity, heart disease, and diabetes are at an all time high in Western populations (Rakhra et al. 2020).
The relationship between diet, health, and our microbiome is becoming increasingly clear as more studies are conducted. Diets that are high in unhealthy fats and sugars lead the gut microbial population to decrease (Townsend et al. 2018), which can reduce the overall health of the host. An unhealthy microbiome could lead to inflammation, obesity, diabetes, and even cancer (Zhang et al. 2015). However, most of the research and understanding of the gut microbiomes focuses on western industrialized populations. This leaves significant gaps of knowledge for those populations who are in non industrialized regions, and possibly leaves a wealth of microbes undiscovered.
Acne vulgaris, more commonly known as acne, is a disease that mostly everyone deals with at some point in their life, most likely in their adolescent years, and can lead to self-esteem issues and negative impacts on mental health (Lee, et. al., 2019). Of course, there are some people who maybe get the occasional pimple, but generally do not have acne-prone skin and to them, people might say they are blessed with good genetics. But is genetics really the outstanding cause of whether you have acne or not? Microbiologists would suggest it is the microbes inhabiting our skin, which are microscopic sized organisms. The skin microbiome, or collection of microbes living on and in your skin, is diverse and can contribute to a number of skin conditions, acne being one of them. There is one specific microbe known to inhabit the skin quite pervasively and progress acne: Propionibacterium acnes. This microbe is able to survive without oxygen within a layer beneath your skin and deep within the hair follicles of the skin.
A study done by Jacob Hall and colleagues in 2018 offers a comparative analysis of the three methods best suited for sampling the skin to determine the presence of microbes. The use of pore strips is one method used in this study, but it is stated that previous studies have emphasized concern they do not reach deep enough to obtain an accurate analysis (Fitz-Gibbon, et al., 2013). Another method used was swabbing the skin surface with a cotton swab, which only obtains information from the surface of the skin and not internal layers, where we know P. acnes to be most abundant. The third method used was cyanoacrylate glue which was able to obtain 50% deeper into the hair follicle than the pore strips were able to. The two methods of data analysis used in this study were 16S rRNA sequencing and whole-genome sequencing (WGS). 16S rRNA sequencing offers microbial identification by amplifying a highly conserved region within all bacteria, while WGS takes the entire DNA sequence and matches the parts of DNA to sequences that are available on public databases to determine which taxa are present.
SEBASTIAN KAULITZKI/SCIENCE PHOTO LIBRARY/GETTY IMAGES
Background
Recently there has been a trend in increasing health and a significant portion of this has been tied to gut health. When it comes to gut health the gut microbiome is typically one of the first topics brought up; along with this comes the topic of maintaining and improving the bacteria in our gut. This is done in two fashions: diets and supplements. Within supplements, the ever more popular probiotics play an extremely important role in our gut health. Not only are probiotics beneficial in aiding digestion and other dietary benefits, but a recent study has shown that they may even suppress the formation of tumors, reduce colon inflammation, and cause the death of tumor cells related to colorectal cancer (CRC) (Zhou et al, 2024).
Recently there has been a trend in increasing health and a significant portion of this has been tied to gut health. When it comes to gut health the gut microbiome is typically one of the first topics brought up; along with this comes the topic of maintaining and improving the bacteria in our gut. This is done in two fashions: diets and supplements. Within supplements, the ever more popular probiotics play an extremely important role in our gut health. Not only are probiotics beneficial in aiding digestion and other dietary benefits, but a recent study has shown that they may even suppress the formation of tumors, reduce colon inflammation, and cause the death of tumor cells related to colorectal cancer (CRC) (Zhou et al, 2024).
Microbiomes are all around us, in your gut, on your hands, in your ear, and especially in your mouth. The oral microbiome is one of the most interesting subjects to study because of the complex environment in your mouth. It’s wet, warm, and depending on the person can have a high or low pH. Many factors come into play when it comes to the health of your oral microbiome. One of those factors is chlorhexidine (CHX), an antiseptic mouthwash that has been around since the 1970s. Dentists regularly use chlorhexidine, so how does this affect our microbiome?
Chlorhexidine is an antiseptic agent that is used because of its long-lasting antibacterial effects and the large spectrum of action. It’s used by dentists because there have been studies that have shown its effectiveness in the clinical management of plaque, gingival inflammation, and bleeding (Amoian et al., 2017). Other studies show that it helps reduce the proliferation of some bacterial species associated with periodontal disease as well as reducing levels of bacteria that colonize the top surface of the tongue (Bescos et al., 2020).
Could you imagine waking up every day with pain that never goes away? That is the reality many fibromyalgia sufferers experience in their everyday lives. Fibromyalgia is from the Latin word fiber (fiber) and the Greek words myo (muscle) and algos (pain). These root words offer a glimpse into what fibromyalgia is and how it causes suffering. It is a pain of the fibrous tissues and muscle in the human body. While anyone of any background regardless of race or ethnicity can get fibromyalgia, it typically affects women more than men (NIH, 2024). You are more likely to develop fibromyalgia as you age, and if a family member has fibromyalgia. There are cases of children and young adults having fibromyalgia, but it usually occurs in middle-aged women (Erdrich et al., 2023).
Around 2 to 4% of adults live with the challenges of fibromyalgia (Stewart, 2022). They wake up, feeling exhausted, struggling to get through daily tasks, and facing unpredictable flare-ups. This chronic condition, along with many other symptoms mentioned can affect your mental health, sleep and cognitive issues like brain fog, chronic headaches, and memory impairment. In addition, It can also make you more at risk for depression and anxiety by more than 50% (Freirich et al., 2021). Figure 1(A) displays many of the possible or common symptoms that sufferers of fibromyalgia have. The National Institute of Health has a great page about fibromyalgia, including its symptoms, causes and an overview.
The human microbiome refers to all the microorganisms that live on and inside us. These microorganisms are predominantly bacteria and can consist of both beneficial and harmful species that change throughout our lives due to different factors. Our facial skin is home to millions of these microscopic organisms, such as bacteria, fungi, and viruses; that influence the health of our skin (Byrd, A., Belkaid, Y. & Segre, J, 2018). These include the bacteria that peacefully coexist on our skin, as well as potentially harmful and dangerous invader bacteria (Scharschmidt TC, Fischbach MA, 2013). These facial microbes function in maintaining the physical barrier of our skin, protection against pathogens, working with the immune response, and the breakdown of natural products (Byrd, A., Belkaid, Y. & Segre, J, 2018).
Aging is a factor that influences the composition and function of the facial microbiome and is unavoidable for all humans. As we get older, our facial skin experiences a decrease in collagen, sebaceous/oil glands, and sweat, which can impact and influence the facial microbiome (Sun, C. et al. 2024). Skin aging is associated with physical changes such as wrinkles, loss of elasticity, and the appearance of rough texture (Kim, HJ. et al., 2022). It has been found that elderly individuals exhibit significantly higher microbiome diversity linked to reduced immune capabilities that are not as effective at eliminating certain bacteria and microbes (Jensen, J. M., & Proksch, E., 2009).
