Foods That May Be Beneficial or Harmful In a Psoriasis Diet

If you have psoriasis, you're already aware that just about anything can trigger those red, itchy, and sometimes painful patches of scaly skin. Skin injuries, cigarette smoking, illness, or changes in the weather are just a few things that are thought to provoke attacks, but what about food? Does your diet play a part in psoriasis flare-ups? And maybe more important—can change it help prevent them?

The answer is: maybe.

"It depends a lot on the patient and their history," Ashley Wentworth, MD, adult and pediatric dermatologist at Mayo Clinic in Jacksonville, Florida, told Health. Everyone has different dietary requirements based on their own needs, Dr. Wentworth said. "But we do know that eating a healthy diet makes people feel better and reduces stress, and that can impact their psoriasis."

Can Diet Impact Psoriasis Symptoms?

As of December 2022, the jury is still out on whether eating certain foods or avoiding others can have a significant impact on the frequency or severity of psoriasis.

A review of studies published in JAMA Dermatology examined whether dietary changes might make a difference in people with psoriasis or psoriatic arthritis. The findings suggest that people who are overweight or obese may be able to reduce the severity of their psoriasis symptoms by losing weight by adopting a low-calorie diet.

"We do know that psoriasis has been linked to obesity," Dr. Wentworth said. "We often encourage weight loss for patients who are not at the weight that has been established as a goal for them with the assistance of their primary care provider."

Per the JAMA Dermatology review, psoriasis patients with celiac disease may find avoiding foods containing gluten helpful in managing their symptoms. "We have done studies to show that if someone has celiac disease antibodies, a gluten-free diet could potentially benefit their psoriasis," Dr. Wentworth explained.

But while there may not be one cure-all, psoriasis treatment diet, evaluating what you eat is still a critical step in managing the disease, said Victoria Yunez Behm, CNS, LDN, manager of nutrition science for the American Nutrition Association.

"Many descriptions of psoriasis focus on causes and conditions that are genetic or environmental in nature but gloss over nutrition or only mention the possibility of foods as triggers," Behm explained. "However, nutrition determines so much of our internal environment and the health of the barriers that protect us, like the lining of the gastrointestinal tract."

Foods To Limit or Avoid

Because psoriasis is an immune-mediated disease, it's not just limited to the skin; it's systemic. So, Behm explains, it makes sense to choose foods that support your overall health and avoid those that don't. Here are a few to consider limiting in your diet:

Anything Ultra-processed

Often loaded with sugar, sodium, and other additives, ultra-processed foods are high in saturated and trans fats and should be avoided, said Bridget Shields, MD, assistant professor, Department of Dermatology, University of Wisconsin-Madison.

"Unhealthy fats are found in partially hydrogenated oils or excessively processed foods," Dr. Shields tells Health. "These are important foods for patients with psoriasis to avoid when possible."

According to a 2018 review in Current Obesity Reports, examples of ultra-processed foods include:

• Pastries, cookies, and crackers
• Ice cream
• Candy
• Processed meat
• Breakfast cereal
• Soft drinks
• Prepared meals

Red Meat and Dairy

According to Dr. Shields, certain animal products, like red and processed meats and dairy, can be pro-inflammatory because they're high in trans and omega-6 fats and may be converted to an unsaturated fatty acid called "arachidonic acid."

"It is important to highlight that not all fats are created equal," Dr. Shields explained. "Omega-3 fatty acids, as found in mackerel, salmon, sea bass, hemp seeds, and chia seeds, are thought to be anti-inflammatory, and omega-6 fatty acids may also have some beneficial systemic effects as well. The safest way to consume omega-6 fats is probably from whole foods, such as walnuts, sunflower seeds, and pumpkin seeds."

High-glycemic Index Foods

The glycemic index measures how quickly a certain food raises the glucose (or sugar) levels in your blood. As you might expect, foods ranking high on the glycemic index (GI) tend to increase blood sugar levels, and maintaining a diet of high-GI foods can lead to a variety of health issues, including an increased risk of cardiovascular disease.

Certain high-glycemic foods may also "worsen psoriatic disease when eaten in large quantities for extended periods of time," Dr. Shields said, and because of that, people with psoriasis may be better off avoiding them. Some examples of high-glycemic foods are:

• White bread
• Bagels
• White rice
• Fruit juices (that don't contain fiber)

Nightshades

"Nightshades are a class of vegetables that some people can react to," Julie Zumpano, RD, a registered dietitian with the Department of Preventive Cardiology at Cleveland Clinic, told Health. "Specifically for psoriatic arthritis, nightshades can be a trigger."

Nightshades contain a substance called solanine that's primarily found in specific vegetables. According to the Arthritis Foundation, no scientific studies (as of December 2022) prove these vegetables cause inflammation or worsen psoriasis symptoms.

According to a small 2017 national survey of psoriasis patients' dietary habits described in the Journal of Dermatological Treatment, more than half of respondents reported skin improvements after reducing their intake of nightshade veggies.

The Arthritis Foundation suggests eliminating nightshades for a couple of weeks if you suspect they cause symptoms. Then slowly add them back into your diet and note whether symptoms change.

Examples of nightshades include:

• Tomatoes
• Potatoes (excluding sweet potatoes)
• Eggplant
• Peppers (hot and sweet)
• Certain spices made from peppers (cayenne, paprika)

Alcohol

Alcohol technically isn't a food, but it still makes the list because of its possible link to both the initial onset of psoriasis and contributing to flare-ups. "We may not have all the science to explain it, but we do see some people can flare with psoriasis if they do have a heavy alcohol intake on a daily basis," said Dr. Wentworth. "That can cause flaring or could potentially be an initial trigger."

It can also render certain psoriasis treatment medications less effective since the liver must do double duty: metabolizing alcohol and systemic medicines people take to manage psoriasis. "If you are having a heavy alcohol intake, that's going to put a strain on the liver, and then it may make have more side effects with these medications."

What To Eat if You Have Psoriasis

While there's no single "best" diet for psoriasis, a Mediterranean diet is a good choice.

Dr. Shields cited large trials demonstrating a wealth of benefits for people following a Mediterranean diet, including reductions in markers of inflammation, decreased body weight, and lower insulin production. "All factors that should, in theory, benefit patients with psoriasis," Dr. Shields said.

Zumpano said that the Mediterranean diet is an excellent diet to try, but like anything, suggested giving it a month or two to see how you respond. "There's trial and error," Zumpano said. "So, if you're going to try a diet to 'cure your psoriasis,' I would do a very whole foods, heavily-plant-based, clean diet, then I would track your flare-ups and see if there was anything in your diet that may have stimulated it."

Here are some foods to include in your diet:

Omega-3 Fatty Acids

According to the National Institutes of Health, omega-3 fatty acids are essential fat the body doesn't produce on its own. When added as part of a healthy diet, omega-3 fatty acids can help improve cardiovascular health, raise "good" cholesterol, and help lower pressure, among other benefits.

The upside for people with psoriasis? Behm said numerous clinical studies confirm the benefits of omega-3 fats for reducing inflammation that accompanies immune-mediated inflammatory diseases like psoriasis.

Foods high in omega-3 fats include:

• Salmon
• Herring
• Sardines
• Shellfish
• Flax seed
• Chia seeds
• Walnuts
• Soybeans

Fruits and Vegetables

"Vegetables are excellent anti-inflammatory foods, as are many fruits, especially those that are on the lower glycemic index and have higher fiber content," said Dr. Shields.

Behm recommended getting creative and eating a "rainbow of fresh plant foods each day," which contain a variety of phytonutrients or compounds with anti-inflammatory and antioxidant properties. Examples include:

• Dark, leafy greens
• Yellow beets
• Pumpkin and other winter squashes
• Blueberries
• Purple carrots
• Radishes

Healthy Fats

"It's important to note that as we are learning more and more about psoriasis, we are learning it can be linked to things like diabetes, high blood pressure, high lipids, or fats in the blood," said Dr. Wentworth.

Dietary fat is essential to your health. What matters is where you get it from. Saturated fat, found in things like baked and fried foods, can lead to increased "bad" cholesterol, while unsaturated fat can help improve cholesterol levels and decrease your risk of heart attack and stroke.

"There are many wonderful foods to embrace if you've got psoriasis," Behm said, and healthy fats are among them. According to Behm, examples of healthy fats include:

• Avocado
• Cold-pressed extra virgin olive oil
• Olives
• Low-mercury, wild-caught fish like wild Alaskan salmon

High-quality Proteins

Psoriasis is associated with inflammation, and eating foods to help reduce it can be beneficial in managing psoriasis, according to the National Psoriasis Foundation, which says that a healthy eating regimen that includes protein foods like fish and beans may help reduce the impact of symptoms or how often they occur.

When it comes to those proteins, Behm suggested opting for "high-quality" sources, whether they're animal or plant-based. Examples of protein foods include:

• Cage-free eggs
• Wild fish
• Beans
• Lentils
• Nuts (almonds and walnuts)
• Fatty fish, like salmon, mackerel, and tuna

Vitamin D

Vitamin D is the main ingredient in two topical prescription medications for psoriasis, and according to Dr. Shields, they work well in helping treat the skin. Based on that, it seems logical that taking vitamin D as an oral supplement could also benefit people with psoriasis. Unfortunately, as of December 2022, there's not a lot of research to back the theory.

"If you look at the data [for] vitamin D supplementation in psoriatic patients, we really don't have good evidence that high-dose vitamin D supplementation is helpful," said Dr. Shields.

That said, it may be beneficial to add it to your diet naturally, and according to the National Psoriasis Foundation, the safest way to do that is through food. Sources of vitamin D include:

• Cod liver oil
• Salmon
• Mackerel
• Tuna (canned, in water)
• Orange juice (fortified with vitamin D)
• Eggs

A Quick Review

Although there isn't a proven psoriasis diet, experts in nutrition and dermatology agree that there are foods to choose from and some foods to consider avoiding that could improve overall diet and reduce inflammation, both of which might reduce the frequency of psoriasis flare-ups. Make note of your dietary changes and any changes in symptoms you experience. Talk to a healthcare provider if you have questions or need help managing psoriasis.