People living in the grip of psoriasis often feel powerless. Taking control of your diet is the most basic way to regain control of your life and fight back against the disease. But can modifying your diet help in treating psoriasis?
There is no definitive answer to this question. Scientists say there's little evidence at the moment to support the notion that diet can have a major impact on the disease. But many people with psoriasis swear they've found relief by changing what they eat. Dropping surplus weight and improving your cholesterol and blood sugar is empowering—even if these changes do little for your skin or joints.
University of Pennsylvania psoriasis researcher Dr. Joel Gelfand supports patients following a healthful diet, but says people should keep their doctors informed about the changes they are making—and be careful not to do anything that might actually cause harm. "The downside [of changing the way you eat] is the time, cost and energy to follow a diet you may not enjoy, and that won't have proven benefits for your health."
Generally speaking, there are four main approaches to diet:
A 2014 study published in the Journal of the American Academy of Dermatology linked obesity to an increased risk for psoriatic disease. Researchers found that a higher body mass index (BMI) is associated with an elevated risk for developing psoriasis and psoriatic arthritis, as well as an increase in the severity of the disease.
Dr. Wilson Liao, the study's co-author, said that obesity may provide the nudge that triggers psoriasis in people who are already predisposed to it. The researchers also found that in overweight individuals, losing weight may improve the effectiveness of treatments. Fat cells secrete cytokines, which are proteins that can trigger inflammation, explained Liao. "So if you lose weight, you may be reducing fuel for the fire."
A study from the same year in the British Journal of Dermatology also identified an association between weight loss and a reduction in psoriasis severity. This study focused on a "dietary intervention" combined with systemic treatment, including exercise, over the course of 20 weeks.
"There was a clear correlation between the amount of weight loss and the improvement of psoriasis," said Dr. Luigi Naldi, the BJD study's lead author. "Patients who lost more weight experienced a larger improvement in psoriasis," he said. Even a small amount of weight loss can have a big impact on disease severity, he added.
The long-term impact of a dietetic intervention on psoriasis remains to be explored. But the results of this study emphasize the importance of weight loss as part of an overall treatment for psoriasis and its comorbid conditions in overweight patients with psoriasis.
In addition to the improvement in psoriasis severity indicated by these results, there are numerous other incentives for obese patients with psoriasis to lose weight. Psoriasis, especially if severe, is associated with an increased risk of cardiovascular morbidity and mortality. Weight loss improves cardiovascular risk factors (e.g. arterial hypertension, diabetes and high cholesterol). Also, obesity may diminish the therapeutic effect of certain medications.
"We know that fat is an inflammatory tissue, so maintaining a healthy weight—and reducing overall body fat—may result in a reduction in systemic inflammation," said Dr. Nehal Mehta, a cardiologist at the National Institutes of Health who studies metabolic disorders and systemic inflammation. "We think that this may, in turn, help with improvement in symptoms of psoriasis and psoriatic arthritis."
"We all have to eat during the day," said Dr. Liao. "If there's a way to turn that requirement into a benefit for our health and for psoriasis, then why not?"
Let's get started
To help identify what is a healthy weight for you, calculate your body mass index (BMI.) You can use this calculator from the Centers for Disease Control and Prevention.
To lose weight, you must burn more calories than you consume. One pound equals 3,500 calories. If you cut 500 a day from your diet, you'll lose a pound a week. People who lose weight slowly, about 1 to 2 pounds per week, are more successful at keeping the weight off. You'll also burn additional calories if you increase your physical activity.
You weight-loss plan should do all of the following:
- Emphasize fruits, vegetables, whole grains, and fat-free or low-fat dairy products.
- Include lean meats, poultry, fish, beans, eggs, and nuts.
- Contain foods low in saturated fats, avoid trans fats, and limit cholesterol and salt (sodium).
- Avoid refined sugars and processed foods.
Some tips to help you lose weight:
- Keep a food diary. Writing down everything you eat is critical! Noting how you feel when you eat will help you identify emotional triggers that may cause you to overeat. Emotional eaters tend to overeat.
- Eat when you're truly hungry rather than when you're tired, anxious or stressed.
- Eat slowly. If you eat too fast, you eat more than you need to satisfy your hunger. Your brain needs time to catch up with your stomach.
- Plan your meals ahead of time so you make healthy choices. When dining out, check the menu online and decide what you will order before you sit down. Ask for dressings on the side. Opt for foods that are baked, broiled or steamed versus fried or swimming in creamy sauces. Avoid chips and bread baskets—they add unnecessary calories.
- Stay hydrated. People often mistake thirst for hunger.
- Eat breakfast. If you skip this meal, you'll be starving by lunchtime. You'll have more difficulty making healthy choices throughout the day.
- Find resources to help you keep track of your food choices and nutritional values, and that can offer additional support when you need it. Try CalorieKing.com and MyFitnessPal.com, which offer a searchable database of foods with nutritional values.
- Before you get started, consult your doctor!
Psoriasis is an inflammatory disease, the same as heart disease. Reducing inflammation and improving heart health are important for people with psoriasis. Here are some recommendations for heart-healthy eating:
- Eat fish at least twice a week. Cold-water fish (such as albacore tuna, mackerel, salmon, herring, and lake trout) contain omega-3 fatty acids that can help lower your risk of coronary artery disease.
- Choose lean meats and poultry without skin. Prepare them without adding saturated fat or trans fat. Baking and broiling are heart-healthy ways to prepare lean meats and poultry.
- Use fat-free, 1 percent fat, and low-fat dairy products.
- Limit foods containing partially hydrogenated vegetable oils. They contain trans-fat.
- Shoot for less than 1,500 milligrams of sodium per day. Read food labels to see how much sodium you're consuming.
- Limit alcohol. If you have severe psoriasis, you may benefit from eliminating alcohol entirely. If you are going to have an occasional drink, the recommendations are: women no more than one drink per day, men no more than two.
- Keep an eye on your portion sizes. Consider weighing and measuring your food until you get used to appropriate sizes.
- Limit the amount of processed and fast food you eat.
Psoriasis is an inflammatory disease. Many individuals have benefitted from following an anti-inflammatory diet to help reduce their symptoms.
"The response to any medical intervention will vary based on individual circumstances, compliance to the recommendations, and genetics," said Dr. Andrew Weil, who directs the Center for Integrative Medicine at the University of Arizona and is the author of numerous best-selling books on diet and health. "However, in my experience, most people respond well to dietary and lifestyle modifications aimed at controlling chronic inflammation."
Foods to avoid because they have been shown to cause or increase inflammation:
- Fatty red meats
- Dairy products
- Processed foods
- Refined sugars
- Nightshade vegetables, including potatoes, tomatoes and peppers
Foods to include in your diet that have been shown to reduce inflammation:
- Cold-water fish (see the Heart-Healthy diet above).
- Flaxseeds, olive oil, pumpkin seeds and walnuts. These are plant sources of omega-3 fatty acids.
- Colorful fresh fruits and vegetables. Choose foods from the colors of the rainbow.
Nutritious examples are:
- Squash and sweet potatoes
- Kale and broccoli
- Strawberries and figs
Many people with psoriasis and/or psoriatic arthritis who are looking for treatments that don't involve drugs are interested in gluten-free diets. They wonder if these diets will improve their condition.
Many studies have evaluated the benefits of a gluten-free diet for psoriasis. The link between psoriasis and gluten (a complex protein found in wheat, barley and rye and in many processed foods, from lunch meats to salad dressings) is not well understood, but new research estimates that up to 25 percent of people who have psoriasis may also be sensitive to gluten. Celiac disease is caused by an intolerance to gluten. A gluten-free diet is the only known treatment for celiac disease.
A number of studies suggest that psoriasis and celiac disease share common genetic and inflammatory pathways. Research further suggests that having psoriasis about doubles your chance of being diagnosed with celiac disease.
There is no published evidence that going on a gluten-free diet can improve psoriasis in people who do not have celiac disease – but there is anecdotal evidence from people who have tried the gluten-free diet and swear by it.
If you suspect you may have celiac disease or cannot tolerate gluten, you may be tempted to eliminate gluten from your diet on your own. But experts advise that you first schedule a blood test to check for the allergy. Talk to your doctor and/or a registered dietitian on how to start a gluten-free regimen.
If you eliminate more than one food at a time, for example, it can be hard to know which food or foods were actually the problem. It could take up to 90 days for any inflammation to subside. A dietician can help you make a list of gluten-free foods to make sure you get the nutrients your body needs.
It is also possible that gluten isn't contributing to your symptoms, but that another food such as dairy, sugar, corn or soy might be.
The challenges of a gluten-free diet
Following a gluten-free diet requires you to become educated on all the hidden sources of gluten, as well as educating everyone you live with. To avoid all gluten, you must read labels carefully. You must avoid not only wheat but its derivatives: durum, graham, kamut, semolina and spelt. The same goes for barley derivatives: malt flavoring and malt vinegar, as well as rye, MSG and soy sauce.
Read labels regularly. Manufacturers change ingredients without notice.
Just because a food is labeled wheat-free doesn't mean it's gluten-free. And just because a food is labeled gluten-free doesn't mean it's calorie-free. Some manufacturers add sugar, saturated fats and preservatives to their gluten-free offerings to make them taste better, and that adds calories.
You can still eat a balanced diet when you're trying to avoid gluten. Gluten-free diets allow you to eat fresh fruits and vegetables. Beef, chicken, fish, lamb, pork and dairy products are also naturally gluten-free. (But watch for additives.)
For someone with psoriasis who does not also have celiac disease and is not allergic to gluten, giving up gluten may not be such a good idea. Following a gluten-free diet is a major commitment. It can be difficult to maintain a balanced diet while eliminating the many foods that contain gluten. It's not a step you should take unnecessarily.
The bottom line on gluten
Eliminating gluten from your diet may help reduce your psoriasis symptoms as well as eliminate digestive woes, but it's only likely to help if gluten is a problem food for you in the first place.
The Celiac Disease Foundation provides a list of foods to eat and those to avoid on a gluten-free diet, it may be helpful to reference when planning your meals.
Vitamins and Supplements
Studies have not shown a direct link between vitamins and dietary supplements and psoriatic disease. Yet many people with psoriasis and psoriatic arthritis find that including vitamins and supplements in their diet helps clear their skin and may ease joint pain.
Dietary supplements can be extracts or concentrates, and they can occur in many forms, such as tablets, capsules, softgels, gelcaps, liquids or powders.
Omega-3 fatty acids have been shown to decrease inflammation, and psoriasis is a disease of inflammation. Omega-3 fatty acids also seem to have a positive impact on the body's immune system.
There are three types of omega-3 fatty acids:
- Alpha-linolenic acid
- Eicosapentaenoic acid (EPA)
- Docosahexaenoic acid (DHA)
Alpha-linolenic acid is found in some vegetable oils, nuts, seeds and soy foods. EPA and DHA are found in fatty fish and algae. Fish oil also is available in capsule form as a supplement. Some individuals with psoriasis show a deficiency of omega-3 fatty acids and elevations of omega-6 fatty acids, which tend to increase inflammation.
The research on whether omega-3 fatty acid supplements can help reduce the severity of psoriasis is mixed. More long-term clinical controlled studies are needed.
Fish oil can thin your blood, so check with your doctor before you start taking it and especially if you are taking Coumadin (warfarin) or other blood thinners.
Vitamin D topical ointments have been around and used to treat psoriasis for some time. Vitamin D is the main active ingredient in two prescription medications – Vectical and Dovonex – that are applied to the skin. Psoriasis increases the growth of the skin's cells. Vitamin D can change the way cells grow and may slow their growth.
Research on whether vitamin D can help alleviate psoriasis symptoms is small and limited. A report in the May 2011 Science Translational Medicine journal found that vitamin D helps counteract the body's response to inflammation associated psoriasis.
Too much vitamin D can be dangerous. Dr. Wilson Liao, co-author of the 2014 study on diet and psoriasis that appeared in the Journal of the American Academy of Dermatology, warned that vitamin D can also cause serious side effects by raising the calcium level in the blood. "Sometimes that can lead to things like kidney stones and maybe even gout," he said.
Before you add vitamin D to your psoriasis regimen, talk with your doctor. The safest source of vitamin D is food:
- Cod liver oil
- Salmon (sockeye)
- Tuna fish canned in water
- Milk, non-fat, reduced-fat, and whole, vitamin D-fortified
- Orange juice fortified with vitamin D
- Yogurt fortified with 20 percent of the daily value of vitamin D
- Eggs, vitamin D is found in the egg yolk
- Swiss cheese
- Fortified cereals
You also can get vitamin D from 10 minutes of midday exposure to the sun. (Prolonged sun exposure has been linked to aging skin and skin cancer and is not recommended!)
A simple blood test can tell you whether you're deficient in vitamin D.
Glucosamine and chondroitin are over-the-counter dietary supplements that can be taken individually or together. They occur naturally in and around the cells of cartilage in the body.
- Glucosamine may help in cartilage formation and repair and possibly inhibit inflammation.
- Chondroitin may promote cartilage elasticity and inhibit the breakdown of cartilage.
A growing body of research shows that these supplements may slow the progression and reduce the pain of osteoarthritis, a degenerative disease characterized by cartilage deterioration of the joints. However, psoriatic arthritis and osteoarthritis are different forms of arthritis and have different symptoms. No studies have found that glucosamine and/or chondroitin supplements effectively reduce symptoms of psoriatic arthritis.
Glucosamine contains substances extracted from animal tissue including shrimp, lobster shells and shark cartilage. People who are allergic to shellfish should avoid glucosamine. Also, children and women who are pregnant or plan to become pregnant should not take these supplements. Glucosamine has been shown to increase blood sugar levels in some people with diabetes. If you have diabetes, talk with your doctor before taking glucosamine supplements.
Methylsulfonylmethane (MSM) is an organic sulfur-containing compound found in plants, fruits and vegetables. However, it is destroyed when food is processed. The body needs sulfur to maintain healthy connective tissue.
You can buy MSM as a dietary supplement. However, there is little scientific evidence that it relieves joint pain or has anti-inflammatory benefits. One 2006 study by researchers at the Southwest College Research Institute in Tempe, Ariz., found that MSM improved symptoms of pain and physical function in patients with knee osteoarthritis without major adverse events. More research is needed.
Researchers have not found significant evidence that selenium or vitamin B12 improved psoriasis conditions.
The bottom line on vitamins and supplements
Things to keep in mind about using dietary supplements to treat psoriasis and psoriatic arthritis:
- Tell your doctor before taking any OTC supplements. Every substance has a potential to interact with your other medications and treatments.
- Supplements should never replace medications your doctor has prescribed.
- The U.S. Food and Drug Administration does not regulate the manufacturing of dietary supplements. Purity, quality, strength and composition can vary widely among different brands.
- Should you take supplements and experience side effects, stop taking them and tell your doctor!