Psoriatic disease is a chronic, inflammatory condition that affects various parts of the body. It occurs when something goes wrong with the immune system and can lead to psoriasis and psoriatic arthritis.
A person with psoriatic arthritis (PsA) will experience swelling, pain and stiffness in the joints, fatigue, and other symptoms. Many people with PsA also have skin involvement, which is the hallmark sign of psoriasis.
No specific diet will cause or treat psoriasis or PsA, but some dietary tips may help.
The foods and dietary habits that may benefit people with PsA are the same as those that reduce the risk of metabolic diseases.
Chronic inflammation appears to play a role in various types of arthritis and metabolic diseases and may worsen symptoms.
Consuming foods that contain fiber and antioxidants may help reduce inflammation.
The Arthritis Foundation encourage people with arthritis to eat fiber, as there is evidence that it can reduce inflammation.
They also recommend following a diet that is high in antioxidants, as studies show that these can help reduce inflammation by helping remove free radicals. Free radicals are a by-product of many bodily processes that can adversely affect health.
Some anti-inflammatory foods that may help include:
- green, leafy vegetables
- green or matcha tea
- many herbs and spices
Foods that provide fiber and antioxidants include:
- fresh fruits and vegetables
- whole grains
- low-fat proteins, such as legumes
- nuts and seeds
- oily fish and other types of fish
The diet should also include healthful fats, such as:
- extra virgin olive oil
- avocado oil
- other vegetable oils
Fish such as salmon, trout, and herring contain healthful fat that is good for heart health. They also provide anti-inflammatory omega-3 fatty acids. A review published in 2018 concluded that fish oil might benefit people with psoriasis.
Animal fats can adversely affect inflammation and overall health. Dairy-free or low-fat dairy products may be better for a person with PsA.
While most vitamin D comes from sun exposure, dietary sources are also important.
Good sources include:
- egg yolk
- fortified dairy products, cereals, and orange juice
- oily fish
Learn more here about vitamins that may help with psoriasis.
Ginger is high in antioxidants and can have anti-inflammatory properties. Three antioxidant compounds that are present in ginger are gingerol, shogaol, and paradol.
A 2014 study found that ginger may help reduce pain in osteoarthritis. However, it did not mention PsA specifically.
The content of ginger in commercial products can vary widely. A person should ask a doctor or dietitian to recommend a suitable product.
Various ginger products are available for purchase online.
Anyone who is considering taking supplements of ginger or anything else should speak to a healthcare professional first.
Curcumin is an ingredient in turmeric.
A 2018 review listed curcumin as one natural remedy that might help people with psoriasis.
Many people enjoy turmeric in a variety of dishes, including soups, rice, stews, and in drinks, such as smoothies, milk, and tea.
Turmeric spice, supplements, and other products are available to purchase in health food stores or online.
A person should ask their doctor before using any supplements, however.
According to the National Psoriasis Foundation, fatty red meats, refined sugars, processed foods, and dairy products can increase inflammation and worsen the symptoms of psoriasis.
Processed foods often contain a highly processed type of fat known as trans fats. These are not healthful fats.
Each of these foods can also contribute to weight gain. Weight gain and obesity have links with psoriasis, and according to some studies, obesity may increase the risk of PsA.
A 2017 review found that losing weight through diet and exercise may decrease overall inflammation and relieve the symptoms of psoriasis and PsA. However, the authors called for more evidence to confirm this.
Foods that may trigger or worsen inflammation include saturated fats from processed foods, simple carbohydrates, sugar, and alcohol.
People with PsA should avoid:
- food and drinks with added sugar, including sodas and candy
- white bread, white rice, and other processed bread and cereal products
- packaged cookies, cakes, and snack foods
- processed meats, such as bacon, sausages, and hot dogs
- fried foods and foods containing trans fats
- alcoholic beverages
The balance of bacteria in the gut can affect overall health, including the immune system, metabolism, and weight. Some scientists have suggested that changes in gut bacteria may increase the risk of PsA.
A study published in 2016 compared the gut bacteria of healthy people and people with PsA.
The authors found that people with psoriasis and PsA had less diverse gut bacteria than healthy people and that they lacked several types of healthful bacteria.
Previous studies had found lower quantities of the same bacteria in people with inflammatory bowel diseases, such as Crohn's disease.
Foods and supplements that may boost the health of gut bacteria include:
Fermented foods: Kimchi, kefir, kombucha, sauerkraut, yogurt, and miso contain beneficial bacteria.
Probiotics: Different types have different functions. An individual should ask their doctor or dietitian to recommend an appropriate option.
Fiber: This can also benefit gut health and gut microbiota, according to a study published in 2018.
Fresh fruits and vegetables, nuts, legumes, and whole grains are all excellent sources of fiber.
Research suggests that people with psoriatic disease are more likely to have celiac disease or a gluten sensitivity, in which a person cannot tolerate gluten. People with celiac disease must avoid all gluten.
If tests find that a person has a sensitivity to gluten, they will benefit from following a gluten-free diet. However, people should speak to their doctor before going gluten-free, as it may not suit everyone.
A gluten-free diet needs careful planning, as it can increase the risk of some nutritional deficiencies.
What is the link between gluten and psoriasis? Learn more here.
Obesity is a comorbidity of psoriatic disease, which means it is more likely to occur in a person with psoriasis or PsA than in those without psoriatic disease.
Obesity and excess weight can put additional strain on joints. It also involves inflammation and may make psoriasis worse.
Maintaining a healthy weight can help a person avoid obesity and other comorbidities of psoriatic disease, such as high blood pressure, high lipid levels, and heart disease.
Following a calorie-controlled diet may help. However, a non-restrictive diet that focuses mainly on fresh fruit, vegetables, and whole grains may also help a person manage their weight.
Learn more here about ways to lose weight.
The Mediterranean diet encourages a high consumption of fruits, vegetables, and fish.
One reason for this may be that the diet contains foods that are high in antioxidants, which could also benefit people with PsA.
Not all studies have confirmed a benefit for people with arthritis, but any diet that contains plenty of fresh, plant-based ingredients is likely to have overall health benefits.
Learn more here about the Mediterranean diet.
The DASH diet does not restrict the intake of food but focuses on fresh, plant-based produce, and whole grains rather than processed foods and red meats.
A diet with overall health benefits may help a person with PsA to manage their symptoms and prevent complications and comorbidities.
Learn more here about the DASH diet.
Experts do not recommend a specific diet for PsA, but a person may benefit from a diet that:
- boosts overall health
- reduces inflammation
- increases fiber intake
- is heart-healthy
- enables a person to manage their weight
- is low in unhealthful fats and added salt and sugar
- contributes to healthful gut bacteria
A diet that emphasizes plant-based foods while limiting the intake of processed foods is likely to be beneficial.