Psoriatic arthritis—a subtype of the inflammatory skin condition, psoriasis—is a potentially debilitating disorder that disproportionately impacts patients with comorbid obesity. Patients with this condition may pin their hopes on diet and nutrition to find relief.

A low-calorie diet that directly reduces body weight (and indirectly lowers inflammation) is the most supported strategy for psoriatic patients, according to research.

Pona A, Haidari W, Kolli SS, Feldman SR. Diet and psoriasis. Dermatology Online Journal. 2019;25(2). doi:10.5070/D3252042883.

 

There’s also a strong interest in other anti-inflammatory diets (like Mediterranean and ketogenic diets) and supplements. Additionally, in some instances, avoiding trigger foods can have positive effects.

 

Here are evidence-based nutritional recommendations you can feel confident sharing with your psoriatic arthritis patients.

 

Encourage low-calorie diets

 

According to a study published in Advances in Rheumatology, an elevated BMI raises the likelihood of someone with psoriasis developing psoriatic arthritis by 50-fold.

Leite BF, Morimoto MA, Gomes CMF, et al. Dietetic intervention in psoriatic arthritis: the DIETA trial. Adv Rheumatol. 2022;62(1):12. doi:10.1186/s42358-022-00243-6.

 

In addition, extra body weight puts added pressure on the joints, increasing pain and disability.

 

Interestingly, the study authors noted, a calorie deficit of 500 calories per day offered significant joint benefits after 12 weeks, even for trial participants who didn’t lose weight.

You can help patients reduce their calorie intake by suggesting the following changes:

• Check nutrition labels and serving sizes to keep portions under control.

• Choose baked or grilled foods over fried foods.

• Fill at least half your plate with non-starchy vegetables. 

• Learn to cook your favorite meals at home instead of eating out.

• Reduce calories from drinks by avoiding sugar-sweetened beverages and alcohol.

• Swap desserts and candy for fresh fruit.

Encouraging patients to keep a food diary or use an app to track their calorie intake can give them better insight into where to cut back.

 

Suggest anti-inflammatory tweaks

Despite the lack of direct evidence, most psoriatic arthritis patients would benefit from anti-inflammatory diet changes, if not for their joints, to protect against common comorbidities (including hypertension and diabetes), ​​per the study in Advances in Rheumatology.

You can help patients shift their diets in an anti-inflammatory direction by:

• Choosing high-fiber carbohydrates over refined carbs

• Increasing intakes of omega-3 fatty acids from seafood and plants (like chia seeds and walnuts)

• Eating colorful fruits and vegetables rich in carotenoids and polyphenols

• Replacing animal protein (particularly red and processed meats) with soy, legumes, and fish

Preliminary studies suggest potential benefits for zinc and vitamin D supplementation, but the evidence isn’t strong enough to warrant a recommendation in non-deficient patients.

Katsimbri P, Korakas E, Kountouri A, et al. The effect of antioxidant and anti-inflammatory capacity of diet on psoriasis and psoriatic arthritis phenotype: nutrition as therapeutic tool? Antioxidants. 2021;10(2):157. doi:10.3390/antiox10020157.

 

Encouraging patients to view food as a source of essential micronutrients rather than supplements emphasizes the importance of diet quality.

 

 

Avoid unnecessary restrictions

One commonly vilified ingredient is gluten.

There’s some strong evidence, according to a study published in Nutrients,

Passali M, Josefsen K, Frederiksen JL, Antvorskov JC. Current evidence on the efficacy of gluten-free diets in multiple sclerosis, psoriasis, type 1 diabetes and autoimmune thyroid diseases. Nutrients. 2020; 12(8):2316. doi:10.3390/nu12082316.

that eliminating gluten reduces psoriasis severity, but only in patients who also test positive for gluten-related antibodies. Not everyone is sensitive to gluten or should expect these improvements. Some studies suggest a higher prevalence of Celiac disease in people with psoriasis. Nonetheless, offering to test the individual for gluten sensitivity is a better approach than making assumptions or blanket recommendations, which may be irrelevant for certain groups in the study in Nutrients.

 

It’s best to encourage patients to focus on goals with the greatest potential impact. For many, following a reduced-calorie diet is enough of a challenge. However, those who suspect a specific ingredient exacerbates their psoriatic arthritis can meet with a registered dietitian to try an elimination diet.

Gordon B. Academy of Nutrition and Dietetics. What is an elimination diet?. August 13, 2019.

Intentionally removing and reintroducing specific foods lets patients track their symptoms under professional supervision.

 

Elimination diets identify triggers but can also help patients overcome a fear of foods that aren’t truly problematic.