Tag Archives: Probiotics. Postbiotics

Ingesting probiotics doesn’t usually help your gut or your skin

Fiber-rich plants, not probiotic supplements, are the best food for your gut and skin microbiomes

Your gut is home to trillions of, and many types of, bacteria, viruses and other microbes that play an important and complex role in establishing and maintaing your health.

The microbes in your digestive tract, collectively known as your gut microbiome, help regulate your metabolism, digestion, physiology, immune function, and even mental health. These microbiota play an important role in your hormones, cardiovascular health, appetite, and brain health.

Prebiotic fibers, complex starches, polyphenols, and Prifs feed the good bacteria (probiotics) that then produce benefical postbiotics.

The gut-skin axis refers to a complex, bidirectional interaction between the gut microbiota and skin health, including skin microbiota, mediated by immunological mechanisms, short chain fatty acids, inflammatory mediators, and neuroendocrine signaling. This interplay suggests that disturbances in gut microbiota can influence skin physiology by modulating immune and inflammatory responses, and dysbiosis of the skin can interupt skin physiology and anatomy that can then negatively impact the gut. This interaction involves multiple systems, including the immune system, the autonomic nervous system, and microbial metabolites with systemic bioactivity, such as short-chain fatty acids (SCFAs), tryptophan, and serotonin derivatives, all of which contribute to cutaneous immune regulation and chronic inflammation.

Gut dysbiosis can have profound systemic effects, especially when that dysbisosis occurs early in life. Beier et al (2025) found that children receiving multiple antibiotic courses before age 2 were more likely to develop asthma, food allergies, allergic rhinitis, intellectual disability, and atopic dermatitis. Recent studies have highlighted the fundamental role of both the gut and skin microbiota in the pathogenesis of various inflammatory dermatoses. In psoriasis, for example, a notable reduction in bacteria from the phylum Actinobacteria and a corresponding increase in the phylum Firmicutes have been observed in the gut, suggesting a microbial imbalance that may at least partially underly the increased proinflammatory state in affected individuals. In the skin, dysbiosis is likewise evident, characterized by an increase in Firmicutes within psoriatic lesions. These shifts in microbial composition reflect a dysbiotic state that likely contributes to chronic inflammation and immune dysregulation (Thye et al., 2022, Nørreslet et al., 2020). Dysbiosis of the skin can interupt skin barrier function, increase inflammation – with that skin inflammation going systemic and possibly effecting the gut, and with dysbiosis of the gut, your gut produces inflammation and doesn’t produce necessary metabolites – both of which negatively affect the skin.

Therefore, supporting and nourishing your gut microbiome is important. However, recent research finds that many US citizens may not be doing this in the best way. The study, published in the journal Clinical Gastroenterology and Hepatology, found that the percentage of US citizens over age 20 using probiotic supplements more than tripled from 2009 to 2023, rising from slightly less than 2 percent of the population to roughly 7 percent. Probiotic use climbed among people under age 20 too.

These absolute numbers are relatively small, but represents a significant increase. However,during the same period, there was little or no increase in consumption of fiber-rich plants. Many studies have found that one of the simplest and most important ways to improve your gut health is by feeding your gut microbes the foods that they thrive on – fibers, starches, polyphenols, and hard to digest proteins. These include fruits, vegetables, beans, nuts, seeds and other foods that are high in fiber, complex starches and proteins that aren’t abbsorbed in the upper intestine, but instead, are hard to digest and pass through to colon where they feed bacteria that ferment them and make important metabolites that support human health. 

Beneficial plant phenols, or polyphenols, act like prebiotics in your digestive tract. They feed good gut bacteria like Bifidobacterium and Lactobacillus, lower bad bacteria, reduce inflammation, and help create helpful post-biotic compounds. “Bad” phenols were produced when bacteria consumed proteins from the host, including proteins found in the mucus lining of the gut. The good phenols, in contrast, came almost entirely from plant-based indigestible proteins in the diet (Prif). Healthy metabolite profiles have been found when Prif are consumed (AbuSalim et al, 2026).

Consider someone, for example, not eating much fiber but taking an Akermansia muciniphila supplement. In these conditions of low dietary fiber and an altered gut microbiota with excessive mucin degradation by A. muciniphila, one can compromise the mucus barrier (leaky gut), increasing susceptibility to inflammation, infection, and pathogenic overgrowth. Elevated A. muciniphila levels have been associated with various diseases and medications, including graft versus host disease (GVHD) and irradiation, and shown to exacerbate infections by enteric pathogens (Tinger and Engevik, 2025).

Probiotic supplements are often marketed for gut health, but there’s little evidence that they can improve or benefit gut health in healthy people, and studies suggest that, in some cases, beyond the example of Akermansia that I pointed out, they can disrupt the composition of your gut microbiome. Humans don’t have the necessary enzymes to metabolize most of the fiber that we eat, but our gut microbes do have those enzymes. When we eat fruits and vegetables, fiber, straches, polyphenols and Prif travels through our gastrointestinal tracts largely intact until they reach the colon, where microbes feast on them. Our gut microbes convert fiber and the other prebiotics into short-chain fatty acids and other compounds that are beneficial to us. These compounds help lower inflammation, improve blood sugar levels and stimulate the production of appetite-suppressing hormones (yes, some act like GLP-1 agonists).

Some studies have found that taking probiotic supplements can reduce microbiome diversity (a key attribute of a healthy gut) and cause other unintended negative effects. In one clinical trial, scientists at Stanford University assigned adults with metabolic syndrome, a group of conditions that raise the risk of heart disease, stroke and Type 2 diabetes, to take a probiotic supplement for 18 weeks. The supplement contained several strains of bacteria thought to be good for metabolic and digestive health. The researchers found that some people showed improvements in their blood pressure and triglyceride levels, but others experienced a worsening of their blood sugar and insulin levels. People randomly taking probiotic supplements, from a highly unregulated industry, can do much more harm to their guts than what the scientists at Stanford found.

The best ways to nourish your gut microbiome

Eat a wide variety of plants: In general, studies have found that the more diverse your vegetable based diet, the more diverse your gut microbiome. The best way to diversify your diet is by eating many different types of plants. You can do that by eating different leafy greens, snacking on different fruits, adding more herbs and spices to your meals, and seeking out a variety of nuts, beans, lentils, seeds and grains. If needed, you can supplement with prebiotics, including fiber, complex starch, polyphenols, and Prif. You’ll feel better, and look better.

Dietary Fiber: Production of Short Chain Fatty Acids (SCFAs) in Gut Mitigate Neurodegeneration and Inflammatory Skin Conditions

Dietary fiber produces SCFAs, such as propionate, in the gut and benefits the nervous system and the skin, including neurodegenerative disorders and inflammatory skin conditions such as psoriasis and atopic dermatitis. Gut derived SCFAs, which can be transported to organs throughout the body, have been found to be beneficial to the skin’s barrier formation.

Two sources of SCFAs in the skin exist. Bacteria on the skin and in the gut produce SCFAs. For example, the commensal bacteria of human skin Staphylococcus epidermidis can ferment the major component in stratum corneum, glycerol, into butyrate. This is one reason I formulate many topical products with glycerin – because it’s a prebiotic for commensal bacteria. Let’s look at how the two microbiomes, the skin and gut microbiomes, affect skin health – and brain health!

Back in 2015, when I first heard of the work of Dr. Thomas Schwarz, M.D., at the University of Kiel, using the SCFA butyrate to successfully treat inflammatory dermatoses, I became intrigued and sourced a form of butyrate (a form that doesn’t stink and provides additional benefits) that had been produced by scientists in Trieste, Italia. We found butyrate to be highly beneficial to inflammatory skin conditions, and I began to formulate a number of our products with butyrate. As I defined it in 2018 (Maguire and Maguire, 2018), butyrate is a postbiotic – a molecule produced by bacteria that has benefit to the host. The form of butyrate we use in our products is a synthetic postbiotic – i.e. it’s a modified form of butyrate that the bacteria naturally produce.

Dr. Schwarz and team found that short-chain fatty acids activate resident skin adaptive immune cells, Tregs, the activity of which is diminished in certain inflammatory skin conditions. In other words, Tregs, which control inflammation in the body, could be activated by the SCFA, butyrate. There are a number of factors that can control inflammation in the body, including the skin. For example, ultraviolet radiation can induce Treg which then inhibit cutaneous immune reactions including contact hypersensitivity.

Other studies from the University of Chicago (Cao et al, 2024) have found butyrate, in a form conjugated to serine, to reduce autoimmunity. The form of butyrate we use in our products at NeoGenesis is conjugated to hyaluronic acid. Using this conjugated molecule we provide the benefit of both butyrate and hyaluronic acid to the skin.  Cao et al, in their beautiful research paper, sum up the importance of butyrate, and I’ll paraphrase from their paper: Butyrate is derived from the microbial fermentation of dietary fiber in the colon and serves as a primary energy source for colonocytes (cells lining the gut) and maintains intestinal homeostasis. Butyrate is essential for protecting intestinal barrier function by facilitating tight junction assembly (key to preventing leaky gut syndrome). As an epigenetic modulator, butyrate is a histone deacetylase (HDAC) inhibitor and can thus alter chromatin structures and regulate gene expression. Through HDAC inhibition, butyrate has been shown to upregulate forkhead box P3 (Foxp3)—a transcription factor involved in the development and function of regulatory T (Treg) cells (important for anti-inflammation)—as well as suppress NFκB activation (NFkB activation is proinflammatory), inhibit the production of interferon-γ (IFNγ) and upregulate PPARγ. In addition to its broad anti-inflammatory activity, butyrate affects immune cell migration, adhesion, cytokine expression, proliferation, activation and apoptosis. Apart from HDAC inhibition, butyrate can also exert anti-inflammatory effects on immune cells, such as dendritic cells (DCs) and Treg cells, by signaling pathways through specific G-protein-coupled receptors: GPR41, GPR43 and GPR109A. Cao et al found concurrent upregulation of CTLA-4 (CTLA-4 inhibits T-cells) on T cells and downregulation of CD86 (CD86 upregulates T-cells) on myeloid cells can synergistically contribute to a more profound suppression of immune activation, ultimately dampening autoimmune responses. Collectively, these properties of butyrate hold promising potential for the development of therapeutic strategies, particularly in the treatment of immunological disorders, including autoimmune diseases.

Considering the gut microbiome, Dr. Chaogu Zheng, Ph.D., professor at the School of Biological Sciences at The University of Hong Kong (HKU) has found that propionate, a short-chain fatty acid (SCFA) produced in the gut, strongly suppressed neurodegeneration in animal models of Parkinson’s disease (PD) by regulating interorgan signaling between the intestine and brain. I’ve previously published the importance of maintaining gut health to prevent neurodegenerative diseases, including the importance of SCFAs, preventing leaky gut, and maintaining the health of the nutrient-absorbing microvilli.

And relevant to the skin, dietary fiber and SCFAs improve epidermal barrier integrity, thereby limiting early allergen sensitization and disease development. Of note in the study by Trompette et al (2022), is the ability of butyrate to alter lipid metabolism in epidermal keratinocytes, particularly following allergen-mediated skin injury.

There’s been quite a buzz about mucus-eating bacteria in the media. And one tech company has received extraordinary amounts of investment to bring out a supplement based on these bacteria (Akkermansia muciniphila). However, if you read the studies underlying company hype, the mucus-eating bacteria did not lead to significant changes in visceral adiposity and body mass index, the primary objectives of the study. Their results also demonstrated that the supplementation with either Pasteurized A. muciniphila or Alive A. muciniphila did not affect the overall structure of the gut microbiome. This finding is consistent with previous data obtained in rodents, finding that the gut microbiome from mice supplemented with alive A. muciniphila was not significantly modified. Other studies have found that prebiotics work better than probiotics to benefit the gut’s microbiome and measures of obesity. This is uncontrolled capitalism at work – distort the science for the benefit of profits to the rich investors. On the other hand, social democracy, where the people’s money funds scientific research at the universities, yields scientific data on which companies, if they choose to be honest, can make informed decisions about the products they bring to market. Many companies, including mine, do our best to make products that are informed by quality science. Unfortunately, their are some companies, often VC- or private equity-backed (see, for example, Morgenson, Leopold, Karma, and Mazzucato), that look for a quick buck through hyping the science. Some of these are pump and dump schemes, of which Ubiome was one – are a fraud.

From Trompette et al (2022)

In light of the data provided by Trompette et al (2022) on the cutaneous barrier, as well as work from others in the gut, the fact that mucus-eroding bacteria are less efficient at producing SCFA, particularly butyrate, further puts the epithelial barrier at risk in dietary fiber-deprived individuals. Importantly, the findings are not not just important to skin and brain. Indeed, a deficiency in the high-butyrate-producing bacteria has also been implicated in patients with Crohn’s disease, a disorder that also results from epithelial barrier impairment.

Polyphenols are important too. Polyphenols from vegetables can increase the abundance of Lactobacillus and Bifidobacterium, while inhibiting the abundance of Clostridium. Polyphenols have potent antioxidant benefits. This is great for strains like Akkermansia muciniphila, which thrive in oxygen-free environments and are at risk from free oxygen radicals.

The bottom line, is eat well to provide your gut the needed fibers and polyphenols it needs to create a balanced and healthy microbiome. Your skin will be healthier. Instead of an overhyped probiotic that results in a lot of dead bacteria in your poop, eat lots of vegetables such as oats (fiber) and oranges (polyphenols) to develop a healthy microbiome.