Review of Integrative Medical Therapies for Psoriasis: The Microbiome, Probiotics, Diet, and Mindfulness

Abstract

Background

Psoriasis is a chronic inflammatory condition with cutaneous and systemic involvement. Although many efficacious treatment options are available, concerns regarding costs and duration of treatment have expanded interest in the role of integrative medical therapies for psoriasis.

Objective

In this review, we aim to provide evidence for the use of integrative medical approaches in the management of psoriasis, namely approaches utilizing the microbiome, probiotics, diet, and mindfulness.

Methods

PubMed/Medline and Google Scholar databases were searched from inception up to 16 August 2023 to identify clinical studies that evaluated how integrative medical therapies affect psoriasis severity. Search terms combined “psoriasis” or “psoriatic arthritis” with terms related to the microbiome, diet, and lifestyle.

Results

Multiple clinical studies have shown that integrative approaches can reduce psoriasis severity. Probiotic supplementation in psoriatic patients decreased PASI scores, decreased inflammatory markers, increased quality of life, and reduced the risk of disease relapse. Intermittent fasting, in the context of Ramadan, decreased PASI scores and plasma CRP levels. Low-calorie diets and low-calorie ketogenic diets have been shown to reduce psoriasis severity. Notably, combining low-calorie diets with biologics and cyclosporine synergistically improved psoriasis to a greater extent than pharmaceutical therapy alone. A gluten-free diet improved psoriasis and reduced antigliadin antibodies in those with hypersensitivity. Mindfulness therapies also improved psoriasis severity with and without phototherapy.

Conclusion

Several studies show that integrative medicine can be used to manage psoriasis. Specifically, probiotic supplementation, diets that promote weight loss or modulate antigliadin antibodies, and mindfulness therapies may improve disease severity.

Introduction

Psoriasis is a chronic auto-inflammatory disease with an incidence of 2%–3% in Europe and North America. ¹ The etiology of psoriasis is multi-factorial but largely driven by the dysregulation of innate and adaptive immune systems leading to an increased inflammation. ¹ Psoriasis is a systemic disease with predominantly skin, joint, and nail involvement. ² In the skin, psoriasis is characterized by the formation of erythematous, scaly patches and plaques that may affect any part of the body. ¹ Psoriasis affecting one or more joints is known as psoriatic arthritis and affects up to 34% of patients with psoriasis. ³ As a disease of systemic inflammation, psoriasis is also associated with several comorbidities including obesity, ⁴ cardiovascular disease, ⁵ metabolic syndrome, and chronic kidney disease. ⁶ Psoriasis also has a significant impact on quality of life, affecting social functioning and interpersonal relationships. ⁷

There have been numerous advances in the treatment of psoriasis over the past century. ⁸ For mild to moderate disease, first-line treatment involves topical therapies such as corticosteroids, vitamin D3 analogues, combination products, and emerging therapies such as the aryl hydrocarbon modulator topinarof and the phosphodiesterase inhibitor roflumilast.^2,9,10 Moderate to severe or refractory psoriasis may require systemic therapy such as biologics. ² Phototherapy can also reduce skin inflammation and inhibit psoriasis plaque formation. While there are effective pharmaceutical therapies available, treatment for psoriasis can be costly to the patient and the health care system.^11,12 Additionally, patients may be reluctant to be on medication indefinitely and are interested in the role that nutrition, supplements, and mind-body interventions play in modulating psoriasis.

There is emerging interest in the use of integrative approaches to improve overall health. Interventions based on the mind-body (meditation, hypnosis, yoga), herbal and nutritional supplements, and alternative medical systems such as Ayurveda, have been termed as complementary and alternative medicine (CAM). ¹³ Notably, one study found that 42% of the US population used at least one CAM therapy. ¹⁴ Additionally, the market value for nutraceuticals and supplements was reported to be approximately $353 billion USD in 2019. ¹⁵ Integrative medicine incorporates conventional medicine with traditional and complementary medicine to synergistically improve patient outcomes and promote cost-effective strategies for chronic diseases. ¹⁶ This review aims to provide evidence for integrative approaches to manage and treat psoriasis and we specifically look at the impact of the microbiome and probiotics, diet, and mindfulness.

Methods

Searches on Pubmed and Google Scholar were conducted from the inception of the databases until 16 August 2023. Search terms included diet, herbs, nutrition, weight loss, food, botanicals, microbiome, probiotics, supplements, PASI score, mindfulness, quality of life, psoriatic arthritis, and psoriasis. Additional filters for randomized controlled trial (RCT) and clinical trial were applied. Clinical studies that evaluated how integrative medical therapies affect the symptoms of psoriasis were selected.

Results/discussion

A summary of various integrative interventions and their effect(s) on psoriasis severity can be seen in Table 1.

Table 1.

The Role of Integrative Interventions on Psoriasis Severity.

Intervention	Duration	Effect of Intervention on Psoriasis Severity	Other Findings
Probiotic capsule containing Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium lactis, and Bifidobacterium longum (1.8 × 109 CFU) 24	8 weeks	49% decrease in mean PASI score	Increased quality of life, decreased hs CRP, IL-6, MDA
Multi-strain probiotic supplement containing 1.6 × 109 CFU25	8 weeks	51% decrease in mean PASI score	Decreased LPS, hs CRP, IL-1
Probiotic capsule containing B longum, B. lactis, and Lactobacillus rhamnosus (1 × 109 CFU) 26	12 weeks	67% achieved PASI75	Lower risk of disease relapse after 6 months
Low-calorie diet (800 to 1000 cal/d) 29	16 weeks	63% decrease in mean PASI score	Increased quality of life
Hypocaloric diet (500 cal deficit) + placebo supplementation 30	12 weeks	23.5% decrease in mean PASI score	Decrease in DAS28-CRP and BASDAI scores
Hypocaloric diet (500 cal deficit) + Omega-3 supplementation 30	12 weeks	18.2% decrease in mean PASI score	Reductions in weight, waist circumference, and body fat
Biologic therapy + low-calorie diet 31	24 weeks	84% decrease in mean PASI score, 86% achieved PASI75	No additional findings
Cyclosporine + low-calorie diet 33	24 weeks	83% decrease in mean PASI score, 67% achieved PASI 75	No additional findings
Low-calorie ketogenic diet (≤500 kcal/d) 38	4 weeks	50% decrease in mean PASI score	No additional findings
Gluten-free diet 43	12 weeks	73% experienced a 35% decrease in mean PASI	Reduction of antigliadin antibodies in 82% of those with improved symptoms
Mindfulness-based cognitive therapy 48	8 weeks	39% decrease in mean SAPASI score	Increased quality of life
Mindfulness (audiotaped meditation-based stress reduction therapy) + phototherapy 49	Variable	Increased rate of psoriasis clearing by 27% in the PUVA group and 43% in the UVB group	No additional findings

Gut microbiome and probiotics

Dysbiosis of the gut microbiome has been associated with psoriasis.^17,18 One 2018 study compared the gut microbiome of psoriatic patients with BMI-matched healthy individuals. ¹⁹ Compared to the control group, psoriatic patients experienced an increase in abundance of the phylum Firmicutes and a reduction of the phylum Bacteroidetes, resulting in an overall increased Firmicutes/Bacteroides (F/B) ratio. ¹⁹ The F/B ratio is involved in intestinal homeostasis and shifts in this ratio are often linked to disease such as obesity, inflammatory bowel disease (IBD), and psoriasis.^19,20 The top two genera of discriminant abundance in psoriasis were Ruminococcus and Megasphera, both from the phylum Firmicutes. ¹⁹ Similarly, a study comparing psoriatic patients to healthy individuals found that the psoriatic gut microbiome followed a specific pattern with an increased abundance of Faecalibacterium, of the phylum Firmicutes, and a decrease in abundance of Bacteroides. ²¹

Another 2016 study compared the abundances of Faecalibacterium prausnitzii, a commensal bacteria, and Escheria coli, a potentially pathogenic bacteria, in fecal samples from patients with psoriasis, IBD, hidradenitis suppurative (HS), and healthy controls. ²² Psoriatic patients demonstrated a significantly lower abundance of F prausnitzii (P < .001) and a higher abundance of E coli (P < .001) ²¹ in their fecal samples compared to healthy controls. In another study comparing psoriatic arthritis patients with healthy controls, the gut microbiome was found to have significant reductions in Akkermansia, Ruminococcus, and Pseudobutyrivibrio, all of which are short-chain fatty acid (SCFA) producers. ²³

As the role of the gut microbiome in psoriasis becomes more established, some studies have sought to investigate whether probiotic supplementation could improve clinical outcomes.

A 2021 study allocated 50 participants with psoriasis to receive either a probiotic capsule containing Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium lactis, and Bifidobacterium longum with 1.8 x 10⁹ colony forming units (CFU) or a placebo for 8 weeks. ²⁴ At 8 weeks, the probiotic group experienced a mean decrease in PASI scores from 10.65 ± 5.12 to 5.39 ± 2.73 whereas the PASI scores in the placebo group increased. Forty percent of patients in the probiotic group reached PASI 50 and 24% achieved PASI 75. Dermatology Life Quality Index (DLQI) and Beck’s questionnaire (BDI) scores were significantly improved in the probiotic group (P = .045 and P = .017, respectively). Additionally, the probiotic group experienced significant reductions in inflammatory biomarkers such as hs-CRP (P = .015), IL-6 (P = .05) and malondialdehyde (MDA) (P = .013). ²⁴

Similar results were found in a 2022 study which assigned psoriasis patients to receive either a multi-strain probiotic containing 1.6 × 10⁹ CFU of bacteria or a placebo for 8 weeks. ²⁵ There were significant improvements in quality of life and reductions in serum lipopolysaccharides (P = .01), hs-CRP (P = .013), and IL-1 (P = .043) in the probiotic group. ²⁵ PASI scores were reduced by 51% in the probiotic group at two months whereas there was no change in the PASI scores in the placebo group (P = .049). ²⁵

In a 12-week clinical study of psoriatic patients, a multi-strain probiotic capsule containing B longum, B lactis, and Lactobacillus rhamnosus (1 × 10⁹ CFU) resulted in a PASI reduction of up to 75% (P < .05) in the treatment group vs the placebo. ²⁶ Additionally, a 6 month follow-up showed a lower risk of disease relapse in the probiotic group. ²⁶

These findings support the theory that psoriasis may be influenced by the gut-microbiome-skin axis and highlight the potential of utilizing oral probiotsic therapies to restore the homeostasis of the gut and improve psoriasis disease symptoms. Notably, the strains included in the probiotic supplements studied do not exactly match the gut microbes that are implicated in psoriasis. However, the probiotic supplements utilized contain strains of bacteria that have been documented to modulate the F/B ratio, such as L rhamnosus, ²⁷ or modulate short-chain fatty acid producing bacteria (Akkermansia, Ruminococcus, and Pseudobutyrivibrio), such as Bifidobacteria. ²⁸ The mechanism of action by which these strains of bacteria may modulate microbes implicated in psoriasis should be further investigated.

Diets and nutrition

Role of weight loss

Emerging epidemiological evidence suggests that an increased BMI and adiposity is more prevalent in individuals with psoriasis than individuals without. ⁴ Furthermore, weight gain can also act as a psoriasis trigger. ⁴ A clinical study examined 60 overweight psoriatic patients who were randomized into one of two groups. The intervention group was placed on a low-calorie diet (800 to 1000 cal/d) for 8 weeks followed by 8 weeks of increased food intake (1200 cal/d). The control group was asked to eat per the national guidelines for a healthy all-round diet without calorie restriction for 16 weeks. ²⁹ After 16 weeks, the intervention group experienced significant weight loss of an average of 15.4 kg greater than the control group (P < .001), a trending decrease in PASI scores (P = .06), and a significant decrease in the DLQI scores (P = .02). ²⁹ Another clinical trial evaluating psoriatic arthritis patients found that a 12 week hypocaloric diet (500 calorie restriction from the patient’s basal metabolic rate) with placebo supplementation improved disease activity scores (DAS28-CRP) and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) scores significantly (P = .001) and reduced mean PASI scores by −23.5%. ³⁰ The addition of omega-3 supplementation to a hypocaloric diet for 12 weeks did not lead to any further improvement in disease activity but it led to significant reductions in weight (P = .004), waist circumference (P < .001), and body fat (P = .006). Overall, this study found that a hypocaloric diet led to improvements in joint disease activity while the addition of omega-3 supplementation did not add further joint disease activity benefit but did improve other weight and body fat related factors. ³⁰

Weight reduction has also been shown to increase the efficacy of psoriasis therapies such as biologics^31,32 and cyclosporine. ³³ In 262 obese patients with moderate to severe plaque psoriasis receiving biologic therapy, a low-calorie diet led to an average improvement in PASI score of 84% for the diet group, and 69% for the control group after 24 weeks. ³¹ PASI 75 was achieved by 85.0% in the diet group and 59.3% in the control group (P < .001). ³¹ Another study evaluating psoriatic arthritis patients on TNF inhibitors observed a higher rate of minimal disease activity (MDA) when patients achieved greater than 5% weight loss after 24 weeks (P = .011). ³² In another 24 week study on plaque psoriasis, there was a PASI 75 response by 66.7% of patients treated with cyclosporine and a low-calorie diet vs 29% of patients who were treated with cyclosporine alone (P < .001). ³³ This evidence suggests that weight loss as an adjunct to traditional pharmacotherapy can potentiate treatment effects.

Weight loss may supplement pharmacological treatment in obese psoriasis patients. However, these findings may not apply to psoriasis patients who are not overweight.

Intermittent fasting

Intermittent fasting consists of dividing the day into fasting and feeding phases of various lengths. Ramadan is a religious period in which intermittent fasting is performed, and it has been associated with weight reduction and health benefits. ³⁴ Three studies have assessed the effects of Ramadan fasting on psoriasis severity (Table 2). The first study evaluated psoriatic arthritis patients who fasted 17 h a day for one month. ³⁵ The participants were allowed to continue concurrent pharmacological therapy. After a month of fasting, serum CRP levels decreased (P < .0001), PASI decreased by 21% from 7.46 ± 2.43 to 5.86 ± 2.37 (P < .0001), and disease activity index for psoriatic arthritis (DAPSA) decreased (P < .0001). ³⁵ The second study assessed 121 patients with plaque psoriasis who fasted during Ramadan and found that the mean PASI score, which was 4.36 ± 3.22 at baseline, significantly reduced by 19% to 3.51 ± 1.26 (P = .001). ³⁶ There were no significant changes in fasting plasma glucose, HDL, or triglycerides. The third study assessed 108 patients with moderate to severe plaque psoriasis and found a significant decrease in mean PASI scores by 25% (P < .0001) after Ramadan associated fasting. ³⁷ Future studies should investigate the effects of intermittent fasting beyond the 4-week period to fully assess the potential of intermittent fasting on PASI improvement.

Table 2.

Clinical Studies Evaluating the Effects of Ramadan Fasting on PASI Score.

Author (year)	Psoriasis Type	Sample Size	Duration of Fasting	Mean % Change in PASI Score	P-Value
Adawi et al 35 (2019)	Psoriatic arthritis	n = 37	1 month	21% decrease	P < .0001
Almutairi et al (2022) 36	Plaque psoriasis	n = 121	1 month	19% decrease	P = .001
Damiani et al 37 (2019)	Plaque psoriasis	n = 108	1 month	25% decrease	P < .0001

Low calorie ketogenic diet

The therapeutic potential of low-calorie ketogenic diets in inflammatory diseases such as obesity and psoriasis is emerging. ³⁸ One study observed that 4 weeks of a calorie restricted ketogenic diet resulted in a 50% reduction in PASI (P = .007). ³⁸ However, the diet followed in this study was highly restrictive with a total caloric intake of less than 500 kcal and may have issues with adherence. Moreover, the sustainability of the results once the diet is stopped is unclear.

Mediterranean diet and red meat consumption

Another diet with therapeutic potential for psoriasis is the Mediterranean diet, which mainly consists of white meat, fish, legumes, and olive oil. In one cross sectional observational study, 62 psoriatic patients and 62 BMI-matched healthy subjects were assessed for their adherence to a Mediterranean diet, PASI score, and CRP levels. ³⁹ The study found that increased PASI scores were associated with higher BMIs (r = .449, P = .001). A higher consumption of extra virgin olive oil (EVOO) (r = −.741, P < .001), vegetables (r = −.600, P < .001), fruits (r = −.628, P < .0010, seafood (r = −.618, P < .001) and nuts (r = −.365, P = .009) led to reductions in PASI scores. Increased consumption of red or processed meats (r = .427, P < .001) led to increases in PASI scores. ³⁹ Another study compared dietary intake habits between 100 patients with psoriasis and 100 controls without psoraisis. ⁴⁰ Notably, 59.5% of patients with PASI scores of <3 (mild) were found to consume red meat frequently (≥3 times/week) and 82.5% of patients with PASI scores 3-10 (moderate) or >10 (severe) were found to consume red meat frequently (≥3 times/week). Psoriatic patients that consumed vegetables more frequently were found to have lower mean PASI scores (r = −.22, P = .014) while patients that consumed red meat (r = .19, P = .029), instant noodles (r = .184, P = .033), or belly meat (r = .178, P = .041) more frequently were found to have higher mean PASI scores. Thus, the dietary choices made by psoriatic patients may influence the severity of their disease.

Role of a gluten-free diet in those with hypersensitivity

Psoriatic patients may have increased serum antibodies to gliadin. ⁴¹ IgA and IgG antibodies to gliadin predict reactivity to gluten. ⁴² One study sought to evaluate the effect of a gluten-free diet in psoriatic patients with antibodies to gliadin. ⁴³ After 3 months, 73% of psoriatic patients that had either an elevated IgG or IgA gliadin antibody that went on a gluten-free diet showed improvement. On the other hand, none of the psoriatic patients that tested negative to anti-gliadin antibodies improved with a gluten free diet. For those that did experience an improvement on the gluten free diet, there was a 35% improvement in their PASI score. Additionally, antigliadin antibodies were reduced in 82% of those with improved symptoms. ⁴³

Other dietary modifications

In a 2016 U.S. national survey, 86% of psoriasis patients reported the use of a dietary modification to control their psoriasis symptoms. ⁴⁴ The greatest percentage of participants reported skin improvement after reducing alcohol (53.8%), gluten (53.4%), nightshade vegetables (52.1%), and after adding omega-3 (44.6%), vegetables (42.5%), and oral vitamin D (41%). ⁴⁴ Additionally, patients noticed skin improvements on the Pagano (72.2%), vegan (70%), and paleolithic (68.9%) diets. Another study from 2020 found that psoriatic patients consuming coffee had lower PASI scores than non-consumers (P < .001). ⁴⁵ However, consuming ≥4 cups of coffee per day led to higher PASI scores. Studies have also found that the addition of dietary products that are rich in antioxidants, such as beta-carotene and flavonoids, have been shown to improve psoriasis severity.^46,47 Additional clinical studies on specific dietary interventions and other diets are warranted.

Mindfulness

Mindfulness-based interventions for psoriasis focus on reducing levels of stress and mitigating the negative impact on quality of life. A pilot study in 2015 randomized 29 psoriatic patients to either their usual psoriasis therapy plus an 8 week mindfulness treatment or to a control group (psoriasis therapy alone). ⁴⁸ The mindfulness group experienced significant improvements in Self Assessed Psoriasis Area Severity Index (SAPASI) (P = .05) and quality of life (P = .02). ⁴⁸ Another study sought to evaluate the synergistic effects of phototherapy with mindfulness. ⁴⁹ Psoriatic patients who were assigned to ultraviolet light therapy plus a meditation-based intervention reached the “halfway point” (the point at which 50% of the original skin surface area involvement remained) and the “clearing point” (the point at which less than 5% of the original are of involvement remained) more rapidly than without mindfulness treatment in both the PUVA and UVB group. ⁴⁹

There are some limitations to this review. Our review did not focus on data for supplements (e.g. curcumin, vitamin D, zinc, etc.), botanical topicals (e.g. aloe vera, Indigo Naturalis extract, Capsaicin, etc.), bile acid sequestrants, or acupuncture even though they have been suggested to influence psoriatic disease severity and future reviews may emphasize these categories of integrative therapies.^50,51

Conclusion

Emerging literature supports the use of integrative therapies for psoriasis management. The gut microbiome, diet and nutrition, and mindfulness have demonstrated a role in disease course and severity, as shown by the reductions in psoriasis severity after targeted interventions. Specifically, probiotic supplementation can be utilized to modulate the gut microbiome, diets that promote weight loss or reduced inflammation can be implemented in the appropriate patients, and mindfulness-based interventions can be utilized in conjunction with conventional therapies. Larger scaled clinical trials that investigate the use of integrative therapies, such as those mentioned in this review, are necessary to confirm these findings in expanded populations. Additionally, these interventions may have synergistic effects when combined and future research on utilizing additive or collaborative therapies is needed.

Overall, this review demonstrates that integrative approaches to psoriasis management can improve patient outcomes. We hope that this review encourages clinicians to consider utilizing integrative therapies when treating psoriatic disorders.

Ethical Statement

Ethical approval and consent to participate

Institutional Review Board approval was not required since a re-analysis of publicly available data was performed.

ORCID iDs

Mildred Min https://orcid.org/0000-0002-6201-7401

Nabeel Ahmad https://orcid.org/0009-0001-2780-1022