Psoriasis is a chronic, recurring, and inflammatory skin disease characterized by silver-white scales covering the skin and other skin inflammations. Although the symptoms manifest on the skin, psoriasis is not solely a skin condition; it is an autoimmune disease.
While psoriasis cannot be completely cured by medication, many patients explore various dietary approaches to manage the condition. Over the years, numerous clinical trials have provided valuable insights into the effectiveness of diet in alleviating psoriasis symptoms.
Psoriasis – Its Relationship with the Immune System and Diet
The exact cause of psoriasis is not fully understood yet, but recent research has shed some light on how it develops. It appears to be a combination of genetic factors (inherited from our parents) and how our immune system reacts to certain triggers.
When someone has psoriasis, their immune system gets activated and sends signals to their skin cells, telling them to grow too quickly. This rapid growth causes an accumulation of skin cells on the surface, forming silver-white scales and patches. These patches can become inflamed and itchy.
Special cells in our skin, called “dendritic cells,” play a role in this process. They encounter these triggers (which can be things like infections or injuries), and they pass the message along to other immune cells known as “T lymphocytes.” These T lymphocytes then become inflammatory cells, specifically Th1 cells, Th17 cells, and Th22 cells [1].
These inflammatory cells release chemicals called cytokines, particularly IL-23, which further stimulates the Th17 cells. Th17 cells, in turn, release IL-17A, causing the skin cells (keratinocytes) to produce more inflammatory substances. This chain reaction leads to the visible symptoms of psoriasis [2].
It’s essential to understand that psoriasis is not just a skin problem; it’s actually an immune disease. This means that our immune system, which is supposed to protect us from infections, mistakenly attacks our own healthy cells in the skin.
Metabolic diseases like obesity and diabetes show a significant association with psoriasis, and weight loss and improvement in metabolic indicators can be beneficial for alleviating psoriasis[3].
What Do Experts Say?
In the 2018 guidelines published by the Medical Board of the National Psoriasis Foundation,[4] they carefully analyzed 55 systematic reviews and other research papers involving 77,000 individuals. Based on this extensive research, they strongly recommend that psoriasis patients who are obese should consider following a low-calorie diet. Moreover, for individuals with psoriasis and gluten intolerance, it is suggested to adopt a gluten-free diet, although this recommendation is not as strong as the one for low-calorie diets.
What Do Psoriasis Patients Say?
In a 2017 dietary survey conducted in the United States among 1,206 psoriasis patients, 86% reported making diet adjustments. Those who saw improvements in their skin condition achieved it through various means: 53.5% reduced alcohol consumption, 53.4% adopted a gluten-free diet, 52.1% excluded nightshade vegetables, 44.6% increased omega-3 fish oil intake, 42.5% added more vegetables, and 41% took vitamin D supplements [5].
Regarding exacerbating foods, sugar was the highest at 12%, followed by alcohol, tomatoes, gluten-containing foods, and dairy – all considered “high-risk” for worsening the condition.
Participants’ experiences with different diets varied. The Pagano diet had the most significant positive impact, reported by 72.2%. Additionally, 70% found a vegan diet (without eggs and dairy) helpful, and 68.9% believed a primitive diet offered benefits. However, only 40.4% of ovo-lacto vegetarian respondents reported positive effects on their psoriasis symptoms.
Reduce Your Calorie Intake to Improve Psoriasis
Psoriasis is closely linked to obesity. A study with a controlled group of 373 psoriasis cases revealed that with every 1-unit increase in BMI, the risk of psoriasis rose by 9%, and the Psoriasis Area and Severity Index (PASI), which measures the severity of psoriasis, increased by 7%. Those with a BMI over 30 (considered obese) had double the likelihood of developing psoriasis compared to those with normal weight [6]. Moreover, several studies have shown that psoriasis patients experienced significant improvements after undergoing gastric bypass surgery.[7-9], highlighting the positive impact of weight loss on psoriasis.
In a 2003 clinical intervention study, 82 psoriasis patients were tested, and a 4-week low-calorie diet resulted in significant improvements in both lipid profiles and the condition of the intervention group subjects [10].
In a 2009 study, participants were divided into two groups: one followed a low-calorie diet with cyclosporine, while the other only used the antibiotic. After 24 weeks, the diet group showed a 7% weight reduction and 66.7% experienced over 75% improvement in their psoriasis severity (PASI) score. In contrast, the control group had no significant weight change, and only 29% achieved the PASI improvement target. A low-calorie diet can lead to weight loss and improve psoriasis symptoms [11].
A clinical study from Thailand in 2013 observed psoriasis patients (with topical medication) following a low-calorie diet for 12 weeks. Afterward, their body weight decreased by 9.6%, and over half of the patients experienced more than a 50% improvement in their PASI score [12].
In a 2013 Danish trial, 60 obese psoriasis patients underwent a 16-week of calorie restriction study. After the trial, the intervention group lost 15.4 kg, and their PASI score significantly decreased from 4.8 to 2.3. The Dermatology Life Quality Index (DLQI) improved from 5.5 to 2.7[13].
Both low-calorie diets and intermittent fasting improve psoriasis. A 2019 Italian study during Ramadan showed significant improvement in psoriasis symptoms. Among 108 participants with moderate to severe psoriasis, the PASI index decreased from 3.54 to 2.65 after fasting, suggesting intermittent fasting’s benefits for psoriasis symptoms [15].
In conclusion, weight loss through calorie restriction, as well as intermittent fasting, can be effective in improving psoriasis symptoms.
Summary
Psoriasis is an inflammatory skin disease with silver-white scales, linked to both genetics and immune system response.
While medication can’t cure it completely, dietary adjustments have shown promise in managing psoriasis.
Weight loss through calorie control has been found to improve psoriasis symptoms.
Expert guidelines recommend low-calorie diets for obese psoriasis patients and gluten-free diets for those with gluten intolerance.
Intermittent fasting may also be beneficial in managing psoriasis.
References:
[1] Visser, M., Kell, D. B., & Pretorius, E. (2019). Bacterial Dysbiosis and Translocation in Psoriasis Vulgaris. Frontiers in cellular and infection microbiology, 9, 7. https://doi.org/10.3389/fcimb.2019.00007
[2] Kanda, N., Hoashi, T., & Saeki, H. (2020). Nutrition and Psoriasis. International journal of molecular sciences, 21(15), 5405. https://doi.org/10.3390/ijms21155405
[3] Barrea, Luigi et al. (2020). Very low-calorie ketogenic diet (VLCKD) in patients with psoriasis and obesity: an update for dermatologists and nutritionists. Critical reviews in food science and nutrition. 1-17. 10.1080/10408398.2020.1818053.
[4] Ford, A. R. et al. (2018). Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review. JAMA dermatology, 154(8), 934–950. https://doi.org/10.1001/jamadermatol.2018.1412
[5] Afifi, L. et al. (2017). Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey. Dermatology and therapy, 7(2), 227–242. https://doi.org/10.1007/s13555-017-0183-4
[6] Wolk, Katarina et al. (2009). Excessive Body Weight and Smoking Associates with a High Risk of Onset of Plaque Psoriasis. Acta dermato-venereologica. 89. 492-7. 10.2340/00015555-0711.
[7] Higa-Sansone, G. et al. (2004), Psoriasis remission after laparoscopic Rouxen-Y gastric bypass for morbid obesity. Obesity Surgery 14 (8):1132–4. doi: 10.1381/0960892041975569.
[8] Hossler, E. W., M. S. Maroon, and C. M. Mowad. (2011), Gastric bypass surgery improves psoriasis. Journal of the American Academy of Dermatology 65 (1):198–200. doi: 10.1016/j.jaad.2010.01.001.
[9] Perez-Perez, L. et al. (2009), Severe psoriasis, morbid obesity and bariatric surgery. Clinical and Experimental Dermatology 34 (7):e421–e422. doi: 10.1111/j.1365- 2230.2009.03406.x.
[10] Rucević, Ivana et al. (2003). The Role of the Low Energy Diet in Psoriasis Vulgaris Treatment. Collegium antropologicum. 27 Suppl 1. 41-8.
[11] Gisondi, Paolo et al. (2008). Weight loss improves the response of obese patients with moderate-to-severe chronic plaque psoriasis to low-dose cyclosporine therapy: A randomized, controlled, investigator-blinded clinical trial. The American journal of clinical nutrition. 88. 1242-7. 10.3945/ajcn.2008.26427.
[12] Roongpisuthipong, Wanjarus et al. (2013). The Effect of Weight Loss in Obese Patients with Chronic Stable Plaque-Type Psoriasis. Dermatology research and practice. 2013. 795932. 10.1155/2013/795932.
[13] Jensen, Peter et al. (2013). Effect of Weight Loss on the Severity of Psoriasis A Randomized Clinical Study. JAMA dermatology (Chicago, Ill.). 149. 1-7. 10.1001/jamadermatol.2013.722.
[14] Damiani, Giovanni et al. (2019). Clinical efficacy during the “Ramadan fasting” with a reduction of PASI score, in moderate-to severe psoriatic treated patients under systemic treatment. A multicenter Italian study on real life.. Nutrients. 11. 10.3390/nu11020277.
[15] Solis, M. Y. et al. (2012). Nutritional status and food intake of patients with systemic psoriasis and psoriatic arthritis associated. Einstein (Sao Paulo, Brazil), 10(1), 44–52. https://doi.org/10.1590/s1679-45082012000100010