Psoriasis is an autoimmune disease that causes inflamed, scaly patches to form on the skin. These itchy patches most commonly form on the knees, elbows, trunk, and scalp, causing significant physical discomfort and affecting body image. (Source)
Many people with psoriasis notice that certain foods affect their skin, either worsening or relieving the inflamed skin patches. A growing body of research supports the observations of psoriasis patients, indicating that food choices can have a powerful effect on inflammatory markers, skin discomfort, and skin appearance in psoriasis. In this article, we’ll discuss 9 foods to avoid if you have psoriasis — and what to eat instead — to support a balanced immune system and healthy skin.
9 Foods to Avoid With Psoriasis
As with many autoimmune conditions, psoriasis can be profoundly impacted by diet. If you struggle with psoriasis, there are 9 foods that may trigger your skin, and you may see improvement if you remove these foods from your diet. Please note that several of the foods discussed in this article are foods that people with psoriasis may benefit from avoiding completely, such as gluten, while other foods, such as nightshades, may only need to be eliminated temporarily while you take measures to correct underlying autoimmunity.
Let’s discuss each of these 9 food triggers in turn.
1. Refined Sugars
Emerging research indicates that imbalances in the gut microbiota, the community of microorganisms that lives in the gut, significantly affect psoriasis. Therefore, dietary factors that shift the gut microbiota in an unhealthy direction may influence the development and progression of psoriasis.
A diet high in refined sugars is one of the most significant triggers for an altered gut microbiome, known as dysbiosis. High intake of refined sugars promotes the growth of inflammatory gut bacteria, which release toxins that can influence skin health.
Animal research indicates that a high intake of refined sugar worsens psoriasis and that switching from a sugary, processed diet to a healthier diet that is lower in sugar can help alleviate this condition. (Source)
Refined sugars to watch out for include cane sugar, high fructose corn syrup, and brown rice syrup. It's essential to read labels carefully to watch for these sugars, as they often appear in otherwise healthy looking foods, such as nut milks and salad dressings.
Healthier sweetener options that are less likely to disrupt your gut microbiome include raw honey, maple syrup, and dates.
2. Industrial Seed Oils
Industrial seed oils are the oils expressed from oilseeds, including canola (rapeseed), corn, cottonseed, grapeseed, safflower, soybean, and sunflower oils. These oils are recent additions to the human diet, only introduced into our food supply in the late 19th century.
While industrial seed oils were framed for many years as “heart healthy” by the food industry, abundant scientific evidence today indicates that these oils are, in fact, very inflammatory due to their high concentration of omega-6 fatty acids. The consumption of large amounts of omega-6 fatty acids from industrial seed oils inhibits the anti-inflammatory properties of omega-3 fatty acids, which can influence inflammation in many organs, including the skin. (Source, Source)
Furthermore, omega-6 fatty acids are delicate and prone to damage by light and heat, including the heat used during cooking. Damaged omega-6 fatty acids are particularly inflammatory to our bodies.
Industrial seed oils are common in processed foods, so cutting processed foods from your diet is an excellent way to reduce your intake of these inflammatory oils. However, industrial seed oils also commonly lurk in restaurant food and even in foods marketed as "healthy," such as some nut milks and gluten-free crackers. When purchasing packaged foods, read labels carefully and steer clear of those that contain industrial seed oils.
3. Processed Foods
Research indicates that a “Western diet,” which is the term used in scientific studies to describe a diet low in vegetables and fruits and high in processed foods, promotes psoriasis. Processed foods may exacerbate psoriasis by promoting an inflammatory gut microbiota. Processed foods frequently contain refined sugars and industrial seed oils which, as we’ve discussed already, can significantly increase inflammation. However, other ingredients in processed foods, such as refined flour and food additives, may further provoke inflammation. (Source)
Cutting processed foods such as fast food, chips, candy, and soda out of your diet is one of the most important nutritional steps to take when you have psoriasis.
Gluten is a common protein made up of smaller proteins found in specific grains, including wheat, rye, barley, and triticale. Gluten affects many autoimmune conditions, and psoriasis is no exception. Research shows an association between celiac disease and psoriasis and that a gluten free diet can alleviate psoriasis symptoms. These findings suggest that some people with psoriasis may benefit by removing gluten from their diets. (Source, Source)
While the mechanisms linking gluten sensitivity to psoriasis aren’t entirely understood, the immune systems of people with psoriasis may react to gluten within the gut, initiating an inflammatory response that extends to the skin. In addition, the immune systems of people with psoriasis may also be less able to clear inflammatory signaling compounds created by the body when gluten is consumed.
Psoriasis can be significantly worsened by alcohol, which may aggravate the condition through several mechanisms. First, alcohol consumption may trigger inflammatory signaling in the skin, exacerbating existing skin inflammation. (Source)
Second, alcohol intake can upset the balance of beneficial and harmful bacteria in the gut, potentially worsening underlying gut imbalances involved in psoriasis. And third, ethanol, the primary component (besides water) in most alcoholic beverages, increases leaky gut. A leaky gut is associated with many autoimmune diseases, including psoriasis, so avoiding foods that worsen leaky gut is crucial for alleviating autoimmunity. (Source, Source, Source, Source)
Some people with psoriasis report that eating nightshade vegetables irritates their skin. The nightshade family of plants, which includes white potatoes, tomatoes, peppers, eggplant, and goji berries, are rich in plant compounds called alkaloids that can promote leaky gut, one of the major underlying factors that drive autoimmunity. Removing nightshades from your diet may soothe your skin if you have psoriasis. (Source)
7. Dairy Products
Dairy is a common food allergen, and skin reactions are a common symptom in people sensitive to dairy. While more research is needed to clarify the role dairy may play in psoriasis, many people with psoriasis find that removing dairy products from their diets improves the health and appearance of their skin. (Source)