Foods to Avoid When You Have Psoriasis

The relationship between diet and psoriasis is a complex one, with a lot of unknowns. “We know that obesity has been associated with inflammation in the body and there are studies that show a relationship between BMI (body mass index) and psoriasis severity,” says Jill Salyards, D.O., a board-certified dermatologist in Knoxville, TN. “Working closely with your dermatologist and maintaining a healthy weight to help improve overall health is the best way to improve psoriasis.” Not everyone with psoriasis is triggered by the same foods, but some edibles are anecdotally more likely to cause a flare than others. Keep an eye out for the following.

A study led by UC Davis Health researchers, published in 2021, found that a diet rich in sugar and fat leads to an imbalance in the gut’s microbial culture, which may contribute to inflammatory skin diseases such as psoriasis. Dr. Toy also points out that foods high in refined sugar, such as cookies, pastries, ice cream, and soda, are believed to increase the risk of obesity, diabetes, heart disease, and stroke. “All of these comorbidities are highly associated with psoriasis, although the exact mechanism is unclear,” he says.

Products made from milk, including cheese, yogurt, kefir, ice cream, and butter, contain lactose (a natural sugar), casein (a protein), and a polyunsaturated fatty acid called arachidonic acid. These may be difficult for some people to digest, and while there’s no definite scientific link between dairy and psoriasis, it may help to limit your dairy intake if you think it’s triggering your symptoms. According to a recent review, the arachidonic acid in dairy products may irritate the inner lining of the intestinal tract and worsen psoriasis symptoms, but more studies are required to confirm a link, says researchers.

Gluten gets a bad rap with numerous inflammatory conditions, and though evidence is not robust, if you’re sensitive to gluten, a gluten-free diet may make a noticeable difference to your psoriasis symptoms, says the National Psoriasis Foundation. Eliminate gluten for at least three months to give the inflammation in your body plenty of time to subside. After three months, if you are unsure if you’ve seen a benefit from eliminating gluten, the NPF suggests adding it back into your diet. Pay close attention to your overall health over the following days, recording any symptoms like increased itching and joint pain.

The nightshade vegetable family (tomatoes, peppers, potatoes, and eggplant) are often included in healthy diet plans due to their hefty dose of vitamins B, C, and antioxidants. But some people with psoriasis find nightshades a trigger for skin flares. A recent study found that people often avoid these foods because they believe it improves their psoriasis symptoms. True? Probably not, according to another report from the Global Healthy Living Foundation that found the number of nightshades a person typically eats would not be enough to trigger an inflammatory response. Bottom line: Skip if you want, but likely not the cause of your flares.

Soy, a commonly grown crop in the U.S., may cause problems for those with autoimmune conditions like psoriasis. Soy and soy oil contain high levels of omega-6 fatty acids, which may promote an inflammatory response, some research suggests. However, another review of multiple studies concluded that the relationship between omega-6 fatty acids and inflammation is complex and still not properly understood. If you think soy might trigger your psoriasis, try eliminating soy protein concentrates and non-organic sources of soy like processed soy cheese from your meals to see if it makes a difference.

When you’re dealing with a condition as frustrating as PsO, it’s tempting to look for every possible trigger cause and eliminate it from your life. But it’s important to know that there is no scientifically proven link between a particular type of food and psoriasis flares, says Dr. Salyards. And because each person’s disease can be triggered by different things, it’s a case of getting to know your own body’s response to the condition and identifying how external factors might cause an adverse reaction. And as with all major dietary changes, says Dr. Salyards, it’s sensible to get advice from a nutritionist first.

Enough of the negative talk! It’s best to focus on foods that can help with PsO, and there are plenty: Experts recommend a balanced diet including fruits, vegetables, whole grains, nuts, legumes, fish, and other lean proteins to help combat inflammation and reduce the severity of psoriasis flares. “In particular, foods rich in omega-3 fatty acids like salmon, flax seeds, and walnuts can have a potent anti-inflammatory effect on the skin,” Dr. Toy says. Top tip: A diet rich in vitamin D, used topically to help soothe flares, may be beneficial, including tuna, eggs, and fortified milk, orange juice, and cereal.

Because psoriasis is an inflammatory disorder of the skin, and certain foods are known to promote inflammation, it makes sense that a person’s diet could contribute to or exacerbate underlying skin disease such as psoriasis, says Dr. Toy. “This is certainly an area that can benefit from further research,” agrees Dr. Salyards. In the meantime, if you find yourself more prone to flares after eating certain types of meals, you don’t need a clinical trial to let you know those are foods you’re better off skipping. In short: There is much we still don’t know about the way diet and psoriasis interact, so for now, trial and error and everything in moderation is the best way to go.