People with psoriasis and psoriatic arthritis face an increased risk of conditions such as heart disease, type 2 diabetes, and stroke. Following a traditional Mediterranean diet can help manage these. It's heavy on olive oil, beans, nuts, legumes and seeds, herbs and spices, fruits, vegetables, grains, fish, and seafood. Poultry, eggs, cheese, and yogurt are eaten in moderation, while sweets and meats are generally avoided.

While fish is part of the Mediterranean diet, it's important enough for its own mention. Foods containing omega-3 fats—particularly salmon, sardines, herring, mackerel, and anchovies—have been found to reduce the severity of psoriasis in some patients.

Some experts have reported success in tempering psoriasis with probiotics, a bacteria found in the intestines and in foods such as yogurt and some supplements.

As with fish, certain oils are recommended because of their anti-inflammatory omega-3 fatty acids, such as olive oil and nut oils. These oils can be used in cooking, for sautéing vegetables, or for dressing a salad. Other oils thought to have beneficial properties include flaxseed, evening primrose and borage, and black currant seed oil.

A 2012 review by the International Union of Biochemistry and Molecular Biology noted the ability of turmeric—a popular spice in curry—to combat inflammation. Using herbs and spices can help lower salt intake, which decreases blood pressure and lowers the risk of heart attack and stroke. In addition, herbs and spices have antioxidant properties.

Foods that trigger inflammation should be avoided. Alcohol should be consumed in moderation, as it tends to worsen psoriasis. Dairy, caffeine, and corn can also trigger inflammation and should be avoided. Gluten may aggravate symptoms, so it’s important for those with the condition to understand how grains such as wheat, barley, and rye affect them.