Psoriatic arthritis (PsA) is a complex and chronic inflammatory disease characterized by the association of arthritis and psoriasis, often combined with related conditions and comorbidities. While treatments for PsA have evolved with the introduction of new biological drugs and small molecules to achieve disease remission or low disease activity in most patients, unmet treatment needs persist for those with persistent symptoms, impaired function, reduced quality of life, or comorbidities. Non-pharmacological approaches, including diet modifications, sleep quality, and physical activity, may provide additional benefits. This article reviews the current evidence on the potential effects of diet in PsA patients.
The Role of Diet in Managing Psoriatic Arthritis
Diet, exercise, and sleep are three pillars of a healthy life. Physical activity is fundamental to prevent cardiovascular disease and obesity. PsA is frequently associated with different comorbidities. Evidence demonstrates an increased prevalence of cardiovascular diseases, mainly linked to chronic inflammation. Risk factors for cardiovascular diseases (hypertension, diabetes mellitus, hyperlipidemia, and obesity) are also increased in PsA when compared with those affected by other inflammatory joint diseases and psoriasis alone. General aspects of well-being, including physical activity, exercise, diet regimens, and sleep quality, are rarely discussed during routine clinical visits but may be relevant for managing psoriatic disease. These elements may also reduce cardiovascular risk, improve the metabolic profile, and improve patients’ quality of life.
The Impact of Diet on Psoriatic Arthritis
When it comes to psoriatic arthritis management, what you eat plays a key role. You want to focus on eating anti-inflammatory foods, as they can help reduce a flare-up. Maintaining a healthy weight is important as well, as any extra weight puts more stress on your joints. Obesity is a known risk factor for causing psoriatic arthritis, as it can increase trauma in the joints and in areas where tendons insert into the joint. Weight management is a very important component in the management of psoriatic arthritis.
Diet Regimens and Their Effects on PsA
Different studies have been published on the effect of some diet regimens on disease activity, pain, function, and quality of life in patients with inflammatory arthritis and osteoarthritis. The rationale to use specific diet regimens such as hypocaloric diet, Mediterranean diet, and ketogenic diet is based on the potential anti-inflammatory effect, with a reduction of expression of cytokines such as IL-1 and Il-6, as seen in animal models of inflammatory arthritis.
Hypocaloric Diet
In PsA, Di Minno et al previously showed that a condition of minimal disease activity was more often achieved by PsA patients starting anti-TNF subjected to hypocaloric diet regimen than PsA patients in free diet regimen. Hypocaloric diet in overweight and obese patients should be implemented.
Read also: The Carnivore Diet and Psoriasis
Very Low Energy Diet
An interesting paper was recently published on the effect of very low energy diet on disease activity in PsA. In this study, obese PsA patients with BMI>33 kg/m2 were asked to follow a very low energy diet with a daily intake of 640 kcal, including recommended doses of vitamins, minerals and other essential nutrients. The diet consisted of four daily portions of powder dissolved in cold or hot water and consumed as shakes or soups. At 6 months, significant improvement of disease activity in joints, entheses and skin was observed. Furthermore, the percentage of patients achieving the minimal disease activity increased from 29% (baseline) to 54% (6 months follow-up).
Low-Inflammatory Diet
A recent systematic review was published on the effectiveness of low inflammatory diet on adults with arthritis. Authors examined seven studies with different interventions (from Mediterranean diet to fish oil and strawberry powder integration). In comparison to a usual diet, very low-quality evidence suggested that a low-inflammatory diet was associated with more weight loss, lower inflammation, improved physical function measures (only for patients with RA) and reduced joint pain.
Ketogenic Diet
No formal studies have been conducted on the effects of ketogenic diet in PsA. This particular diet regimens may have an effect on systemic inflammation by reducing insulin production, by the increasing in beta-hydroxybutyrate and glucagon production. This peculiar effect of ketogenic diet may further lead to a decrease of several proinflammatory cytokines and weight loss, with potential beneficial effects.
Intermittent Fasting
Some interesting information is coming from a study on PsA patients during the Ramadan fasting. In this work, authors demonstrated that intermittent fasting improved the clinical manifestations of PsA, including PsA disease activity scores, enthesitis and dactylitis.
The Role of Diet Supplementation in PsA
The role of diet supplementation with prebiotics or other molecules in terms of their potential effects on disease activity, was further evaluated.
Read also: Keto Diet Arthritis Research
Prebiotics
Prebiotics are foods (typically high-fibre foods) that regulate human microflora and are used with the intention of improving the balance of these micro-organisms.
N-3 Polyunsaturated Fatty Acids (PUFAs)
Kristensen et al demonstrated, in a randomised double-blind, placebo-controlled trial, that PsA patients receiving n-3 polyunsaturated fatty acids (PUFAs) showed a significant reduction in non-steroidal anti-inflammatory drug and paracetamol use compared with controls after 24 months. Moreover, a trend to a reduction of disease activity in terms of tender joints, enthesitis and skin involvement was also observed, although not significantly in comparison to placebo.
Eicosapentaenoic Acid-Ethyl-Ester (EPA) and Docosahexaenoic Acid-Ethyl-Ester
Lassus et al performed an interventional uncontrolled study on 80 plaque psoriasis (PsO) patients, of which 34 had PsA, with a medication containing 1.122 mg/day eicosapentaenoic acidethyl-ester (EPA) and 756 mg/day docosahexaenoic acid-ethyl-ester in capsules. This study showed a statistically significant reduction of severity of the psoriasis, measured by the Psoriasis Area and Severity Index (PASI) (PASI change: 3.56-1.98 after 8 weeks). In PsA, improvement was recorded by the percentages of patients reporting severe/moderate/mild/no pain, observing that the proportion of patients complaining of severe pain decreased after treatment.
Efamol Marine
Veale et al, in 1994, examined in a small trial the potential benefits of Efamol marine, a compound of evening primrose oil and fish oil (rich in omega-3 and omega-6 fatty acids), in 38 patients with PsA. They found no effect on parameters of skin or joint disease activity, nor in the NSAIDs supply for PsA patients. However, they noted a decrease in serum leukotrienes and tromboxanes, consistent with an anti-inflammatory effect.
Probiotics
Probiotics are defined as a foods or supplements that contain live microorganisms intended to maintain or improve the normal bacterial microflora in the body. The vast majority of evidence on the use of probiotics coming from inflammatory bowel disease and RA studies, in which some data suggest a possible role in reducing disease activity and even disability in both conditions. One randomised double-blind study was performed in psoriasis patients and evaluated a combined probiotic mixture of Bifidobacterium longum, Bifidobacterium lactis and Lactobacillus rhamnosus. At 12-week follow-up, 66.7% of patients in the probiotic group and 41.9% in the placebo group showed a reduction in PASI of up to 75% (p<0.05). In PsA, a small open-label pilot study in 10 patients with stable disease showed a reduction of disease activity index and faecal level of calprotectine and zonulin after receiving 3 g of probiotic containing corn starch, maltodextrin, fructo-oligosaccharide P6, inulin P2, vegetable protein and bacterial strains of Lactobacillus and Bifidobacterium. Furthermore, Jenks et al performed a monocentric double-blind randomised controlled trial that investigated the effect of a 12-week course of oral probiotics on disease activity, fatigue, quality of life and intestinal symptoms in SpA patients. All patients had active disease; the majority was classified as ankylosing spondylitis (49/63). The primary outcome was BASFI, but various other patient-reported outcomes were assessed at 12 weeks. No significant differences between the placebo and probiotics arms were observed.
Read also: Carnivore Diet for Arthritis?
Dietary Recommendations for Managing Psoriatic Arthritis
Dietary interventions, when implemented, should be used in conjunction with standard medical therapies for both PsA and psoriasis. Select foods, nutrients, and dietary patterns may affect psoriasis, but the evidence is of low quality. To see if any foods make your symptoms worse, cut out one food or food group at a time. This will help you understand which one affects your psoriatic arthritis. For example, don’t cut out gluten and nightshades at the same time. There isn’t one diet to manage all psoriatic arthritis pain and stiffness.
Foods to Include in Your Diet
- Foods high in omega-3 fatty acids: Studies have shown that eating omega-3 fatty acids can help those with psoriatic arthritis decrease their joint tenderness and joint redness and how often they need to use over-the-counter pain relievers. Foods that are high in omega-3 fatty acids have been found to have antioxidant properties, as well as anti-inflammatory properties. Consuming omega-3 fatty acids is also good for your heart health and your general health. Foods high in omega-3 fatty acids include fatty fish like salmon, sardines, and tuna, edamame, hemp seeds, walnuts, and chia seeds.
- Foods high in antioxidants: You also want to consider adding fruits and vegetables, as well as other foods, that are high in antioxidants to your diet. Antioxidants are known to help decrease the amount of oxidative stress that comes from chronic inflammation. Foods that are high in antioxidants include berries like blueberries and blackberries, dark leafy greens like spinach and collard greens, nuts, dark chocolate, tea, and coffee.
- Whole grains high in fiber: Additionally, eating whole grains that are high in fiber can be helpful in managing your psoriatic arthritis. Research shows that for people with psoriatic arthritis, there’s a connection between weight, blood sugar, and chronic inflammation. High-fiber whole grains are digested slowly, which helps reduce any blood sugar spikes. Foods that are good sources of whole grains include corn, quinoa, brown rice, and whole wheat. A high-fiber diet can promote healthy gut flora and helps maintain a healthy weight, which is helpful for those with psoriatic arthritis.
- Fruits and vegetables: Enjoy all the colors of both. Eat at least nine servings a day. Be sure to include citrus fruits, such as oranges and grapefruit. They have a lot of vitamin C. Other research shows that eating foods with vitamin K, such as spinach, kale and broccoli, can reduce inflammation.
Foods to Avoid
- Red meats: The saturated fats in red meat can make inflammation worse. Eat chicken, fish, or beans and legumes instead.
- Dairy products: Like red meat, the saturated fats found in dairy can cause inflammation. Swap out dairy products for plant-based products like soy milk, almond milk, or coconut milk.
- Sugar: Sugar releases small proteins called cytokines that cause inflammation.
- Processed foods: Items like cereal, cheese, and frozen meals tend to contain trans fat, which can trigger inflammation. These types of foods are known to increase inflammation, and they can also cause an increase in your weight, which is not good for psoriatic arthritis.
- Alcohol: It makes your liver work harder and disrupts the way your organs work together.
- Diet soda: If it’s sweetened with aspartame, your body might think that’s a foreign substance and start an immune response.
- Fried foods: They contain trans fats that can start inflammation throughout your body.
- Processed meats: They contain saturated fats, which can make inflammation worse.
Popular Diets and PsA
- Weight Loss Diet: In a weight loss diet, you limit fats, sugars, and carbohydrates. You eat more fruits, vegetables, lean meats, and low-fat dairy items.
- Anti-Inflammatory Diet: Avoid foods like fatty red meats, dairy, refined sugars, processed foods, and possibly vegetables like potatoes, tomatoes, and eggplants (you might hear them called nightshades). Choose fish, like mackerel, tuna, and salmon, which have omega-3 fatty acids. Those have been shown to reduce inflammation. Carrots, sweet potatoes, spinach, kale, and blueberries are good choices, too.
- The Paleo Diet: This way of eating favors meat, fish, eggs, fruits, and vegetables. You’ll avoid all grains, beans, sugary snacks, and dairy. Doctors have no proof that the paleo diet stops PsA symptoms. But you could have less swelling because you’re not eating fatty foods and dairy products.
- Mediterranean Diet: The Mediterranean diet includes fresh fruits, vegetables, nuts, whole grains, and healthy fats. People following this diet rarely eat red meat, dairy, and processed foods.
The Importance of Sleep
Without enough sleep, people tend to overeat and choose unhealthy foods. Sleep deprivation affects the body’s release of ghrelin and leptin, two neurotransmitters that tell our brain when to consume calories. People who are sleep deprived are more drawn towards high-calories foods. It has been showed that acute total sleep deprivation significantly increased cortisol levels. Sleep disturbance is an important feature of PsA and may be present even in patient with only psoriasis.
The Importance of Exercise
Exercise for the management of inflammatory arthritis is recommended in clinical guidelines to manage symptoms, to reduce disability and for the prevention and treatment of comorbidities.
A Case Study: Whole Food Plant-Based Diet
A 40-year-old female teacher presented to the rheumatology clinic in 2003 with nonspecific back, knees, and right ankle pain. She was subsequently diagnosed with psoriatic arthritis and was taking methotrexate to control her disease. Over the years, her symptoms were mostly under control. However, in 2018, after adopting a whole food plant-based diet free of added salt, oil, and sugar, she was able to stop taking methotrexate. She was discharged from the rheumatology clinic and has remained symptom-free since.
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