Thinning scalp hair shouldn’t be a big deal, given that its primary job—to protect against cold and sun—is easily satisfied with a hat or sunscreen. But a thick shiny head of hair also signals health and fertility in the mammalian kingdom, a role that is upended by age and disease in the prism of natural selection. In healthy young men, genetic inheritance can lead to premature balding, often causing social and psychological stress (though shaved heads are fashionable).

A cure is elusive. Though treatments are numerous (drugs, hormones, transplants), less-than-perfect results, costs, and side effects propel researchers to identify a better option.

The microbiome of the skin and gut are areas of interest.

Hair loss, in brief

Under normal conditions, humans lose about 50–100 hairs daily. But if loss exceeds that, then it is a symptom of alopecia, an umbrella term for many types of hair loss. Alopecia can be caused by genetic hormonal disturbances, psychological conditions (depression, and stress), poor nutrition, chemotherapy, and others.

Each hair follicle cycles through four phases: growth or anagen, transition or catagen, resting or telogen, and returning growth. A full cycle can last anywhere from 2 to 5 years per follicle. Unusual hair loss and thinning occur when a follicle is stuck in the telogen or resting phase.

The most common form of hair loss is called androgenetic alopecia, caused a genetically determined excessive response to androgens. Men with this condition, called male pattern baldness, can begin suffering hair loss as early as their teens or early 20s. Women too can be afflicted, but commonly at a later age.

Several treatment medications including minoxidil and finasteride are popular but may come with side effects. Various other treatments for hair loss are available: natural products, pills, hormonal modifications, hair transplants, restorations, extensions, stem cell treatment, and platelet-rich plasma. Effectiveness is variable, making a search for a perfect solution ongoing.

Another type, alopecia areata, is strongly linked to autoimmune reactions causing inflammations at the site of the hair follicle. Autoimmune responses can lead to collapse of the hair follicle. Genetic disposition, environmental factors, and the skin microbiome may influence the condition as well.

Skin microbiome in alopecia areata

Compared to healthy subjects, those with alopecia areata in a small study hosted at the genus level an increase of Propionibacterium (reclassified as Cutibacterium) and a decrease of Staphylococcus. A higher abundance of pathogenic taxa in the hair follicle can lead to infections and can contribute to a pro-inflammatory state on the scalp.

Gut microbiome in alopecia areata

Gut microbial composition in alopecia areata patients was distinct from that of healthy controls, in a recent study. Gut dysbiosis may be related to an abnormal growth of hair follicle cells and eventual hair loss but a clear association has not been determined.

Fecal microbiota transplants (FMT) have been highly successful in treating recurrent Clostridium difficile infections. A bonus effect may be hair regrowth. Two patients after FMT for recurrent C. difficile infections also showed notable improvement in their alopecia areata.

In another case report, an 86-year-old man presenting with noninfectious diarrhea, depressive disorder, and patchy alopecia areata underwent six rounds of FMT. In addition to marked improvement in diarrhea and depression, the patient reported new hair growth “with some of his white hair gradually turning to black, without taking any other therapies for alopecia areata before and after FMT.”

Probiotics and alopecia

Animals

A 2012 study evaluated the effect of a topical product fermented by backryeoncho (extracted from prickly pear cactus fruit) and a strain of Lactobacillus rhamnosus on hair growth in mice. The daily application showed more significant hair growth promoting effect than that of minoxidil.

Another study tested the effects of a strain of Lactobacillus reuteri added to drinking water of aged mice. More lustrous fur, more anagen-phase hairs and higher proliferation of sebocytes (cells that produce sebum, a component of the epidermal barrier and skin immune system) were seen than in control mice. The follicular shift from predominantly telogen or resting phase (in control mice) toward a robust 70% of follicles in anagen or growth phase was particularly noteworthy. The researchers also demonstrated that the probiotic-triggered features of the fur required inflammatory cytokine Interleukin-10 competency in host animals. Different strains of Lactobacillus reuteri have different effects, acting as anti-inflammatory or pro-inflammatory, a differential, which will affect impact.

Humans

Researchers in South Korea recently investigated the effect of administration of two Korean fermented vegetable dishes (kimchi and cheonggukjang) on patients with hair loss. The study found that four months of probiotics-enriched food interventions significantly enhanced hair counts and hair thickness. The exact probiotic content (Leuconostoc holzapfelii, Leuconostoc mesenteroides, and Lactobacillus sakei) was variable making results difficult to attribute to probiotic content alone. Lack of a placebo control group was another limitation. The authors suggested that the observed improvements in hair count and thickness may have resulted from initiation of the anagen phase in hair follicles secondary to the improved blood flow and modulation of androgenetic effects by probiotics.

The clinical evidence for the use of topical or oral probiotic therapy in hair loss is thin. But probiotics may be beneficial agents in capacities that may be relevant to several causes of alopecia. Evidence shows specific probiotics may fight immune-related inflammation, attenuate anxiety and depression, improve blood lipid profiles, improve peripheral blood circulation and moderate some hormonal systems.

Takeaway

Hair loss can be caused by many things. More so than genetic inheritance, metabolic and environmental origins may prove to be linked to the alterations in the skin microbiota as well as the gut microbiota. Both sites may one day be valuable targets for reducing scalp hair loss. For now, a general strategy to prevent dysbiosis with a healthy diet and probiotic foods and/or supplements may be your best bet to keep a shiny head of hair.

 

Key references

Choi, Jae-Chul et al. “In vivo hair growth promotion effects of ultra-high molecular weight poly-γ-glutamic acid from Bacillus subtilis (Chungkookjang).” Journal of microbiology and biotechnology vol. 25,3 (2015): 407-12. doi:10.4014/jmb.1411.11076

Constantinou, Andria et al. “The Potential Relevance of the Microbiome to Hair Physiology and Regeneration: The Emerging Role of Metagenomics.” Biomedicines vol. 9,3 236. 26 Feb. 2021, doi:10.3390/biomedicines9030236

De Pessemier, Britta et al. “Gut-Skin Axis: Current Knowledge of the Interrelationship between Microbial Dysbiosis and Skin Conditions.” Microorganisms vol. 9,2 353. 11 Feb. 2021, doi:10.3390/microorganisms9020353

Faraj, Janine et al. “The Gut-Brain Axis: Literature Overview and Psychiatric Applications.” Federal practitioner : for the health care professionals of the VA, DoD, and PHS vol. 38,8 (2021): 356-362. doi:10.12788/fp.0159

Ho CH, Sood T, Zito PM. Androgenetic Alopecia. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK430924/

Lee, Heejae et al. “Functional properties of Lactobacillus strains isolated from kimchi.” International journal of food microbiology vol. 145,1 (2011): 155-61. doi:10.1016/j.ijfoodmicro.2010.12.003

Lee, Joon et al. “Characterization of the anti-inflammatory Lactobacillus reuteri BM36301 and its probiotic benefits on aged mice.” BMC microbiology vol. 16 69. 19 Apr. 2016, doi:10.1186/s12866-016-0686-7

Levkovich, Tatiana et al. “Probiotic bacteria induce a 'glow of health'.” PloS one vol. 8,1 (2013): e53867. doi:10.1371/journal.pone.0053867

Lu, Jinghao et al. “Gut microbiota characterization in Chinese patients with alopecia areata.” Journal of dermatological science vol. 102,2 (2021): 109-115. doi:10.1016/j.jdermsci.2021.04.003

Park, Dong Wook et al. “Do Kimchi and Cheonggukjang Probiotics as a Functional Food Improve Androgenetic Alopecia? A Clinical Pilot Study.” The world journal of men's health vol. 38,1 (2020): 95-102. doi:10.5534/wjmh.180119

Piao, Yin-Zi, and Jong-Bang Eun. “Physicochemical characteristics and isoflavones content during manufacture of short-time fermented soybean product (cheonggukjang).” Journal of food science and technology vol. 57,6 (2020): 2190-2197. doi:10.1007/s13197-020-04255-2

Pinto, Daniela et al. “Scalp bacterial shift in Alopecia areata.” PloS one vol. 14,4 e0215206. 11 Apr. 2019, doi:10.1371/journal.pone.0215206

Polak-Witka, Katarzyna et al. “The role of the microbiome in scalp hair follicle biology and disease.” Experimental dermatology vol. 29,3 (2020): 286-294. doi:10.1111/exd.13935

Poller, Wolfram C et al. “Lipoprotein apheresis in patients with peripheral artery disease and lipoprotein(a)-hyperlipoproteinemia: 2-year follow-up of a prospective single center study.” Atherosclerosis. Supplements vol. 30 (2017): 174-179. doi:10.1016/j.atherosclerosissup.2017.05.007

Quraishi, M N et al. “Systematic review with meta-analysis: the efficacy of faecal microbiota transplantation for the treatment of recurrent and refractory Clostridium difficile infection.” Alimentary pharmacology & therapeutics vol. 46,5 (2017): 479-493. doi:10.1111/apt.14201

Rebello, Dionne et al. “Hair Growth in Two Alopecia Patients after Fecal Microbiota Transplant.” ACG case reports journal vol. 4 e107. 13 Sep. 2017, doi:10.14309/crj.2017.107

Rizk, Maryan G, and Varykina G Thackray. “Intersection of Polycystic Ovary Syndrome and the Gut Microbiome.” Journal of the Endocrine Society vol. 5,2 bvaa177. 16 Nov. 2020, doi:10.1210/jendso/bvaa177

Simakou, Teontor et al. “Alopecia areata: A multifactorial autoimmune condition.” Journal of autoimmunity vol. 98 (2019): 74-85. doi:10.1016/j.jaut.2018.12.001

Song, J.H., Lee, J.S. & Choi, H.J. Hair growth promoting effect of essence manufactured with products fermented by Lactobacillus rhamnosus and Backryeoncho (Opuntia ficus-indica var. sarboten) fruits in mice. Food Sci Biotechnol 21,1101–1104 (2012). https://doi.org/10.1007/s10068-012-0143-9

Xie, Wen-Rui et al. “Hair regrowth following fecal microbiota transplantation in an elderly patient with alopecia areata: A case report and review of the literature.” World journal of clinical cases vol. 7,19 (2019): 3074-3081. doi:10.12998/wjcc.v7.i19.3074

Zarezadeh, Meysam et al. “Probiotics act as a potent intervention in improving lipid profile: An umbrella systematic review and meta-analysis.” Critical reviews in food science and nutrition, 1-14. 24 Nov. 2021, doi:10.1080/10408398.2021.2004578

 

Authorship

Clare Fleishman RDN, MS is a Registered Dietitian with the Academy of Nutrition and Dietetics and holds a master degree in nutrition science. She bridges the gap between science and health across most platforms: major newspapers, magazines, books (Globesity), workshops, social media and websites. From corporate whiteboards to refugee schools in Egypt, Fleishman agitates for personal and public change. In 2010, she launched www.ProbioticsNow.com to share the cascade of new discovery in the microbiome. Always amazed at this “forgotten organ” Fleishman also creates white papers, blogs, videos and social media for the International Probiotics Association as well as continuing education platforms.

The International Probiotics Association (IPA) is a global non-profit organization bringing together through its membership, the probiotic sector’s stakeholders including but not limited to academia, scientists, health care professionals, consumers, industry and regulators. The IPA’s mission is to promote the safe and efficacious use of probiotics throughout the world. Holding NGO status before Codex Alimentarius, the IPA is also recognized as the unified “Global Voice of Probiotics” around the world.

IPA disclaimer:

Probiotics have different characteristics, qualities and actions that are unique to the specific strain or combinations. The label should identify the genus, species and strain for each microorganism in the product (i.e. Lactobacillus acidophilus IPA001). If a claim pertaining to individual strains or a blend of strains contained in the product is made, the manufacturer should maintain evidence that the amount(s) provided in the product is consistent with the scientific evidence in support of the claim.