Psoriatic arthritis (PsA) is a type of swelling in the joints that happens in people who have psoriasis. That’s a skin condition that causes red, scaly, itchy patches on the elbows, knees, or scalp. About 30% of the people who have psoriasis get PsA.

If you have it, you might wonder if changing your diet could help you feel better. The Psoriasis Foundation says there’s no real evidence it’ll have a major impact. But it did find that many people with psoriasis had milder symptoms when they ate healthier foods.

With that in mind, let's look at some of the most popular diets and how they might help if you have psoriatic arthritis.

Weight Loss Diet

This is any basic diet that helps you shed pounds. A 2014 study found that people who were overweight had a greater risk for psoriatic disease. Another study found that people who lost weight had less-severe psoriasis. Doctors aren’t sure why this is, but they do know that fat tissue releases proteins that cause swelling. In a weight loss diet, you limit fats, sugars, and carbohydrates. You eat more fruits, vegetables, lean meats, and low-fat dairy items. When you lose weight, you’ll not only feel better -- you’ll lower your risk for getting other diseases, too, like diabetes and high blood pressure.

Anti-Inflammatory Diet

PsA causes swelling. So do certain foods, like fatty red meats, dairy, refined sugars, processed foods, and possibly vegetables like potatoes, tomatoes, and eggplants. Avoid them and choose fish, like mackerel, tuna, and salmon, which have omega-3 fatty acids. Those have been shown to reduce inflammation. Carrots, sweet potatoes, spinach, kale, and blueberries are good choices, too.

Autoimmune Protocol (AIP) Diet

This plan has an official-sounding name, but it’s really an offshoot of the Paleo diet. You’ll cut back on gluten and refined sugar. There’s an elimination phase where you’ll avoid grains, legumes, nightshades, dairy, eggs, coffee, alcohol, sugar, oil, and food additives. The idea is to get rid of anything that might cause inflammation while bulking up on nutrient-dense foods, bone broth, fermented foods, and exercise. You can work the excluded foods back in slowly, figuring out what works for you and what doesn’t. A study found this plan helped people with ulcerative colitis and Crohn’s disease achieve remission. That’s promising news, though there are no studies on how it works with psoriatic arthritis.

Gluten-Free Diet

Research shows that as many as 25% of people with psoriasis may be sensitive to this protein that’s found in wheat and barley. It's used in processed foods as a thickener. It’s not found in fruits and vegetables, rice, meat, beans, potatoes, and dairy. Talk to your doctor before you start this diet. They may test your blood to see if you’re allergic to gluten.

Leaky Gut Diet

While doctors say there’s no such thing as a leaky gut or a specific diet for it, you’re still likely to hear about it. People who believe it say that bacteria and toxins enter your bloodstream through openings that result from Crohn’s disease or taking too many aspirins. In fact, research shows that intestinal permeability can help you absorb water and nutrients. Fad diets have popped up telling you to stay away from foods with high sugar content, whether it’s fruit or processed products, or that things like yeasts, gluten, and lactose can damage your intestinal wall. If you have problems with these things, not eating them will make you feel better, as will cutting back on sugary, processed foods. Never trust anyone trying to sell you leaky gut diet products.

Low-FODMAP Diet

Another eating plan that works well for people with irritable bowel syndrome might be worth a try. FODMAP is a nickname for a group of carbohydrates called fermentable oligo-saccharides, disaccharides, mono-saccharides, and polyols that are hard to digest. They’re found in fruits, honey, some dairy, wheat, onions, garlic, legumes, and artificial sweeteners. Though there’s no proof it works for psoriatic arthritis, you can cut them from your diet for 4 to 6 weeks, then gradually work them back in and see if you feel better.

Mediterranean Diet

A 2014 study showed that eating a diet high in extra-virgin olive oil could make psoriasis symptoms less severe. That’s because it has omega-3s. It also contains oleocanthal, which relieves swelling. If you choose this way of eating, you’ll get to have lots of cold-water fish, whole grains, fruits, and vegetables.

Pagano Diet

People with psoriasis said their symptoms improved while eating this plan, which calls for boosting fruits and veggies while cutting back on nightshades and junk food. But keep in mind, self-reported results are not the same as scientifically tested and proven results. Positive changes often follow when you add healthier foods to the menu.

Paleo Diet

Also called the caveman diet, this way of eating favors meat, fish, eggs, fruits, and vegetables. You’ll avoid all grains, beans, sugary snacks, and dairy.

Doctors have no proof that the Paleo diet stops the symptoms of PsA. But you could have less swelling because you’re not eating fatty foods and dairy products.

Don't get started with any of these diets until you get your doctor's OK. That way he or she can keep track of the changes you’re making and determine whether they’ll help or worsen your PsA symptoms.

Also, get exercise along with any food changes you make. It’s good for your joints and will also ease swelling and arthritic pain.

WebMD Medical Reference

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WebMD Voices

Jaime Lyn M., 42
Detroit
Living with psoriatic arthritis is like playing Pac-Man. You gobble up dots (do your daily activities) before the ghosts (psoriatic arthritis symptoms) get you. Cherries are like medicine -- they turn the ghosts invisible for a little while.
Cynthia C., 50
Moreno Valley, CA
I thought that exercising would increase the pain in my hips, but movement has actually decreased the inflammation and has increased my mobility. Now I take two walks daily.
Michele S., 68
Cornville, AZ
While others may not be able to understand fully the pain and challenges you face, it doesn’t mean they can’t care. Talk openly and share your struggles and strengths with those who ask.
Cynthia C., 50
Moreno Valley, CA
Don't let pain keep you from moving your body. Start slow by doing what you can, even just 5-minute walks. Then make it a daily habit and increase as your body allows.
Josh B., 39
Tampa, FL
My chronic pain got so bad that I couldn't hold a pencil. My wife and I decided as a team that the potential benefit to my quality of life was worth the risk of trying a biologic. Two weeks later, I was able to resume my normal work routine.
Jaime Lyn M., 42
Detroit
Psoriatic arthritis is the hidden component of the psoriasis that people can't see. I try and educate everyone I can on the chronic pain so they understand what I deal with, often daily.

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