Is Choosing the Mediterranean Diet Right For You and Your Psoriatic Disease?

Psound Bytes Transcript: Episode 172

Release date: August 09, 2022

“Welcome to this episode of Psound Bytes, a podcast series produced by the National Psoriasis Foundation, the nation’s leading organization for individuals living with psoriasis and psoriatic arthritis. In each episode someone who lives with psoriatic disease, a loved one or an expert will share insights with you on living well. If you like what you hear today, please subscribe to our podcast and join us every month at Psound Bytes for more insights on understanding, managing, and thriving with psoriasis and psoriatic arthritis.”

Shiva: My name is Shiva Mozaffarian and joining me today for a discussion about the Mediterranean Diet which for many years has been considered an example of an anti-inflammatory diet is Dr. Adam Ford, Chief Resident with UC Davis Health, Department of Dermatology in Sacramento, CA. Dr. Ford was the lead author of the “2018 Dietary Recommendations for Adults with Psoriasis or Psoriatic Arthritis from the Medical Board of the National Psoriasis Foundation” which offered a review of studies addressing the impact of dietary interventions in people with psoriasis and psoriatic arthritis. Joining Dr. Ford is registered dietitian, Danielle Baham, who is the senior Dietitian with Supportive Oncology and Survivorship at UC Davis Comprehensive Cancer Center also in Sacramento, CA. Danielle helps address changing nutritional needs associated with a cancer diagnosis. Additionally, she also helps the NPF provide accurate dietary information for publication when needed.

Welcome Dr. Ford and Danielle! Thank you so much for taking time to be on Psound Bytes™ today. So let's start with the question that many people have. Dr. Ford,  is there an association between the types of foods someone eats and the amount of inflammation or severity of psoriatic disease someone has?

Dr. Ford: So thank you so much for inviting me to be here today. I'm really excited to be able to share the findings from our review on diet and psoriasis and also to do more of a deep dive into the evidence on the Mediterranean diet in psoriasis. And this is such an important question from our patient's perspective about the impact of food on psoriasis. It's something we're frequently asked about in clinic. The most well-known association is between obesity and psoriasis. Psoriasis is more likely to occur in patients who are obese and obese patients have more severe disease on average. So for these patients, foods  like vegetables and fruits, nuts and whole grains and lean meats and other protein sources can all be part of a healthy diet that can lead to weight loss and improvement in psoriasis. And we also know that there is an association between diet and the amount of inflammation people have in general. Certain foods can increase or decrease inflammation in the body by affecting blood sugar levels, antioxidant levels, and the bacteria that live in our gut. For our patients with psoriatic disease, researchers are still working to uncover the association between specific foods and disease severity, but we do have some early data on this topic. So recently there have been studies showing benefit from a Mediterranean style diet, with foods such as extra virgin olive oil, vegetables, legumes, fruits, seafood and tree nuts. And another study suggested benefit from increased consumption of omega-3 fatty acids, fiber and complex carbohydrates. Other studies have highlighted patient reported perceptions on the impact of specific foods on their disease, and these studies do not prove an association between these specific foods and disease severity, but they can still provide useful information. In these studies, patients have reported improvement of their psoriatic disease from foods like vegetables, fruits and fish, while on the other hand, they've reported worsening of their disease from foods like sugar, alcohol, junk foods, gluten, dairy, processed meats and fried foods.

Shiva: So Dr. Ford, you were the lead author of the “2018 Dietary Recommendations for Adults with Psoriasis or Psoriasis Arthritis”. What dietary interventions were concluded as a result of the evidence reviewed by the medical board?

Dr. Ford: Well, for this 2018 study, we performed a systematic review of all the medical literature published on the topic of diet and psoriasis up to that point in time. We found 55 studies that we ended up reviewing and used to formulate our recommendations, which we grouped into five different categories. First, we asked if gluten free diets are helpful in psoriasis and based on the literature, the answer to this question is really that it depends.  For psoriasis patients who have confirmed celiac disease, a gluten free diet is very important and helpful, can lead to improvement of both gastrointestinal symptoms like diarrhea and psoriatic disease. But also there appears to be a subset of psoriasis patients who do not have celiac disease but do have a sensitivity to gluten that can be demonstrated with blood tests. And for these patients, a gluten free diet may be helpful. It's important to note that only patients with active gastrointestinal symptoms like chronic diarrhea should be tested for gluten sensitivity because there's a high rate of false positive tests. The next category we looked at was the impact of dietary weight reduction on psoriatic disease and we found that weight loss with a low-calorie diet can be very helpful for overweight and obese patients with psoriasis in terms of improvement of their psoriatic disease, their quality of life and weight loss in general. And we found that these improvements from dietary weight loss can last for an extended period of time. The next group of studies looked at whether any dietary supplements are helpful in psoriasis, and several studies have shown that psoriasis patients use dietary supplements and these patients have reported improvement with fish oil and vitamin D. However, when we reviewed the medical literature on this topic and we focused on high quality studies, we found limited to no evidence supporting the use of dietary supplements, and this included fish oil and vitamin D but also selenium, vitamin B12 and combination regimens of vitamins and minerals. Next, we looked at literature on the impact of specific foods and dietary patterns. Research in this area was pretty limited and we mostly found observational studies that described the dietary patterns of psoriasis patients rather than studies that looked at the impact of foods and diets on disease severity. But we did find some limited evidence that led us to recommend patients to consider a trial of a Mediterranean diet or a diet rich in omega-3 fatty acids, monosaturated fatty acids, fiber and complex carbohydrates. And the last and fifth set of recommendations, we looked specifically at the impact of all of these interventions in patients with psoriatic arthritis and we found that dietary weight reduction in the overweight and obese patients can lead to greater improvement in their arthritis when used in combination with their standard medical therapies. And we also found that vitamin D supplementation may be helpful for these patients with psoriatic arthritis.

Shiva: Thank you so much for that overview, Dr. Ford. So I’m curious, did the NPF medical board include review of evidence around use of anti-inflammatory diets such as the Mediterranean diet and is there any evidence to suggest that using a Mediterranean diet is helpful for people with psoriasis or psoriatic arthritis?

Dr. Ford: Yeah, we did review all the existing evidence on the use of the Mediterranean diet in patients with psoriatic disease, but it's important to note that our study was conducted in 2017 and so we were only able to include literature available at that point in time, which was rather limited. We found one 2015 study that showed the dietary patterns of patients with psoriasis tend to be less aligned with the Mediterranean diet compared to the dietary patterns of control patients. And this study also showed that amongst psoriasis patients, lower psoriasis severity was associated with greater adherence to a Mediterranean diet in general and lower disease severity was also associated with using extra virgin olive oil as the patient's main fat source. So this is the study that led to our recommendation that adults with psoriasis may consider a trial of a Mediterranean diet as a supplement to their standard medical therapies for psoriasis.

Shiva: It’s so good to hear that the Mediterranean diet was included as part of the review. So Danielle, since our focus today is on the Mediterranean diet, can you tell us what exactly it is?

Danielle: Well, the Mediterranean diet is a way of eating that is traditional in the countries that surround the Mediterranean. So picture Greece, Italy and Spain. Also countries like Egypt, Morocco, Libya and Asian countries as well. Syria, Lebanon and Israel.  Its emphasis is on plant-based foods, fruits, vegetables, whole grains, beans and legumes, fatty fish and olive oil. It also includes moderate amounts of lean poultry, dairy and eggs.

Shiva: And how does the Mediterranean diet compare with what a typical Western diet is? What are the key differences?

Danielle: The typical Western diet is high in sugar, fats,  including saturated fats and trans fats, salts, processed foods, red meats. It's high in high fat dairy and low in fiber. So with all those things, that type of eating is considered inflammatory because it's not providing any beneficial benefits to ourselves or our gut microbiome. So, the key differences between the Western diet and the Mediterranean diet is the Mediterranean lifestyle dietary pattern includes focuses on whole foods. So just think more plants. Half of your plate really should include lots of green leafy vegetables. This way of eating is high in fiber, which also is helpful for our gut and helpful for our colon. It's high in antioxidants and think of antioxidants as those plant nutrients that are anti-inflammatory that also helps protect against cell damage.

Shiva: So how important is eating a healthy, balanced diet and is the Mediterranean diet considered to be such a diet? You already mentioned healthy fats versus unhealthy fats.

Danielle: A healthy diet, balanced diet is important for disease prevention in general. So when you think of the Western diet, it's linked with increased rates of obesity, cancer, diabetes and heart disease. The Mediterranean diet has been ranked as one of the number one dietary lifestyles or habits that we can follow and has been demonstrated over years and decades actually to improve health outcomes. One of the key components of this diet are healthy fats. So you think what in the world is a healthy fat?  Healthy fats are plant based which includes nuts, seeds, avocados, extra virgin olive oil and these foods contain monounsaturated fats. Monounsaturated fats help reduce cholesterol. Again, it's one of those anti-inflammatory ingredients or foods that we eat that help with heart health and disease prevention. They also contain Omega-3 fatty acids, especially your fatty fish like salmon, sardines, walnuts include Omega fatty acids. And again, those are anti-inflammatory foods to help with disease prevention. In contrast, saturated fats do just the opposite. They can clog our arteries and increase our risk for multiple chronic diseases.

Shiva: Danielle, thank you so much for providing an explanation of the Mediterranean Diet. Dr. Ford, Danielle mentioned the Western diet is linked to heart disease and diabetes. We know people with psoriasis and psoriatic arthritis have a higher risk of cardiovascular and metabolic disease. Given what Danielle just described, what's the evidence behind use of the Mediterranean diet versus the Western diet and the impact on inflammatory diseases such as cardiovascular and/or metabolic disease?

Dr. Ford: It's been well established in the medical literature that the use of a Mediterranean diet versus a Western diet has beneficial impacts on inflammatory diseases beyond the skin. A well-known study from 1971 first demonstrated a clear relationship between cholesterol levels in the blood and the risk for the development of cardiovascular disease. And as Danielle mentioned, western diets are often high in unhealthy fats and cholesterol. Subsequent studies demonstrated that Mediterranean populations in Europe, like people from Greece and Southern Italy showed low mortality rates from ischemic heart disease compared to the people of northern Europe and North America. More recently, a large randomized controlled trial performed over eight years in Spain showed that a Mediterranean diet can reduce the risk of major cardiovascular events like heart attack, stroke and death related to heart problems. And it can also decrease rates of metabolic syndrome, diabetes, hypertension and breast cancer. Additional studies have demonstrated beneficial effects on obesity and decreased markers of inflammation in the blood. So taken together, these studies have confirmed the beneficial effects of the Mediterranean diet both in primary and secondary prevention of cardiovascular disease.  And this means that a Mediterranean diet can have a beneficial impact on cardiovascular health for both seemingly healthy patients and patients who already have known cardiovascular disease. And these benefits can be so important to our patients with psoriatic disease who are already at a higher risk for these cardiovascular and metabolic comorbidities.

Shiva: So you just mentioned a recent study with benefits for cardiovascular disease. Since it’s been about five years since the dietary recommendations were published in 2018, are there any recent clinical studies that support use of the Mediterranean diet in people with psoriasis and psoriatic arthritis?

Dr. Ford: Yeah, I'm so glad you asked this question because there are and it's very exciting since the literature on this topic was so limited at the time we formulated our dietary recommendations. I wanted to mention two additional clinical studies that have come out in the last few years. First, a large scale 2018 study conducted in France evaluated the dietary patterns of patients with severe and non-severe psoriasis and they found that those with severe psoriasis had a lower adherence to the Mediterranean diet. So this led the authors to conclude that a Mediterranean diet may help prevent progression of psoriasis from mild to severe disease. Next, a 2020 study of patients with psoriatic arthritis found that patients whose diets were most closely aligned with the Mediterranean diet had lower disease severity on average, compared to patients whose diets were the least aligned with the Mediterranean diet. So these newer studies are really exciting addition to the literature on this topic and they add to the growing evidence supporting the use of the Mediterranean diet.

Shiva: Interesting. Thank you, Dr. Ford, that's really good information to know. So for both of you, how would someone start a Mediterranean diet? Dr. Ford, do you have any comments?

Dr. Ford: Yeah. So I do want to mention that it's important for all patients to check in with their primary doctor before beginning any dietary modifications because people all have unique medical histories and dietary needs. In terms of actually getting started with the diet, I think I'll leave this one to Danielle since she's the expert here.

Danielle: Thank you. Yes. So how to start? You can start slowly by switching the type of oil that you use in cooking. Try the extra virgin olive oil in your cooking or on your salads. You could make your own homemade oil and vinegar dressing. Try a new fruit or vegetable each day. That's an easy way to get in the number of servings that you need per day and eventually per week you can slowly increase. Visit your local farmers market to get an idea on the different  seasonal fruits and vegetables that you can begin to include in your diet and also try a new whole grain. There are so many out there including barley or couscous or just traditional brown rice. You can also try going meatless once a week. That could be an initial goal and also try to include salmon once a week.

Shiva: Thank you, Danielle. So you’ve mentioned examples of food included in the Mediterranean diet. What could a typical day’s menu look like? Can you give an example of a breakfast, lunch and dinner?

Danielle: Yes. So for a typical day’s menu, try a breakfast that includes oatmeal with walnuts and dates or even Greek yogurt and fresh berries. Your lunch could include a salmon filet with brown rice, have a green salad on the side with your oil and vinegar dressing and you can top it off with garbanzo beans and feta cheese. For dinner some more beans. They have a great 15 bean, a dried bean soup mix and to add some extra punch to it add a handful of kale or spinach for an extra boost of antioxidants.

Shiva: Thank you Danielle. So are there any limitations or cautions of use with the Mediterranean diet?

Danielle: I would say, as Dr. Ford mentioned, check with your doctor to see if this is an option for you. There can be if you have underlying conditions such as irritable bowel disease where you wanna caution with the amount of fiber that you're eating. You don't wanna cause further stomach upset, or if you have underlying kidney disease, you have to pay attention to your labs and potassium and phosphorus, and things like that. So those are just a couple of examples of cautions for some patients. And again, that's why it's best to check with your doctor before beginning any new eating plan.

Shiva: Such good advice. We’ve heard some people with psoriasis have concerns about eating nightshades such as tomatoes, peppers or eggplant. Dr. Ford, is that something they should be concerned about?

Dr. Ford: So from my review of the literature, we did find some patient reported concerns about nightshade. So when they surveyed psoriasis patients, some of them reported that when they ate nightshades, it caused flaring of their disease. But we didn't find any studies that actually looked at the amount of nightshades patients were eating and the severity of their disease, or interventional studies where they took a group of people and had them eliminate nightshades, for example. So we don't really have any good data on this.

Shiva: Definitely good to know. And Dr. Ford, is it possible the Mediterranean diet could help with weight loss? You mentioned the association between obesity, cardiovascular and metabolic disease. How important is weight loss to reducing inflammation and risk of comorbidities to improve outcomes of psoriatic disease?

Dr. Ford: Absolutely. The Mediterranean diet can definitely help with weight loss. There have been many studies demonstrating the beneficial effects of the Mediterranean diet and they've shown significant weight loss in patients adhering to this diet. And this point about weight loss is so important to our patients with psoriatic disease. Like you mentioned I touched on this at the start of our conversation and there is this well-established link between obesity and psoriasis. So psoriatic disease is more likely to occur in patients who are obese and obese patients tend to have more severe psoriatic disease. This association may be caused by the well-known ability of fat cells to increase overall levels of inflammation in the body. And at the end of the day, we already know weight loss is important for all overweight and obese patients for many reasons, including positive impacts on cancer risk, cardiometabolic health, things like heart disease, stroke risk and diabetes. And this is especially true in our patients with psoriatic disease, who we already know have an increased risk of these comorbidities.

Shiva: So Dr. Ford, from our conversation it sounds like eating a healthy diet is really a beneficial and integral part of managing psoriasis and psoriasis arthritis. Do you agree?

Dr. Ford: Absolutely. I do think that eating a healthy diet can play a very important role in managing psoriasis and psoriatic arthritis. A number of studies have shown that patients with psoriatic disease also believe that eating a healthy diet is an important part of managing their disease. But all that being said, dietary changes and interventions should always be considered as supplemental to standard medical therapies for psoriasis. So this means that dietary changes should not be used on their own to manage psoriatic disease.  Several studies have shown that dietary changes can lead to an improved response to standard medical therapies for psoriasis. But they're not enough to maintain the benefit if these medical therapies are stopped. So when my patients ask about making dietary changes, I always encourage them to do so. But I also stress the importance of continuing their psoriasis medications.

Shiva: What a perfect message, thank you so much. So Danielle, where can someone go to obtain more information about the Mediterranean diet?

Danielle: Well, the first one is the Academy of Nutrition and Dietetics. They have a wealth of information not only on the Mediterranean diet, but different recipes for you and your family. And also there is an option to find a dietitian in your area to help with guidance on following the meal plan. How to access the Academy of Nutrition and Dietetics is eatright.org. And one of my favorites is oldways.org. And this is a nonprofit organization that helps people live healthier lives and it also has a great resource for recipes, cookbooks that you can order for your home or download if you want to go green. And also, they have a great Mediterranean diet food pyramid which I love because it's a great visual that you can post up on your refrigerator for yourself or your family to remind you also of the base of the pyramid and more emphasis on plants in this diet and just a reminder every day.

Shiva: It's always great to have more resources so thank you. Thank you Danielle and Dr. Ford for being here with us  today. It’s been such an enlightened discussion about the Mediterranean diet. I hope our listeners found this information helpful as well. Do you have any final advice you'd like to share with our listeners?

Dr. Ford: First, I'd just like to thank you so much for inviting me to be a part of this discussion today. It's exciting to be able to share the findings from our recent study with your listeners, but also to provide updates based on more recent literature. In terms of final advice, I'd like to say that I know making lifestyle changes, including dietary changes can be very difficult. So don't be too hard on yourself if you have setbacks or you're not perfect in following a specific diet all the time. Remember that lifestyle changes are always a work in progress, and even small changes can have an impact. And then finally, I'd also just like to remind the listeners that this is an active area of research. So we're likely to learn more about this topic through additional studies in the coming years and hopefully new findings will give our patients even more information on ways to help improve their psoriasis.

Danielle: Yes, thank you for including me on this topic. As mentioned, always try and include a dietitian when you're making any sort of lifestyle changes. We are a great resource for credible information and again, the Mediterranean diet is more of a lifestyle, not where you're counting carbs or counting calories, things like that. So Dr. Ford mentioning, you're not gonna be perfect all the time, but step out and see if this is something for you. Hopefully it is. Even small changes in the types of foods that you're eating or small amounts of weight that you're able to lose are just beneficial overall for improved health outcomes for you and your family.

Shiva: Thank you Dr. Ford and Danielle for your words of inspiration and for sharing your expertise about dietary interventions such as the Mediterranean Diet. A reminder, August is Psoriasis Action Month. Whether you’re looking for treatment options, community, tips and tricks for living a healthy lifestyle or our free healthy eating guide, the National Psoriasis Foundation has the solution you need. Contact our Patient Navigation Center by calling 800-723-9166 or by emailing education@psoriasis.org. Your solution is waiting! Get free resources, individualized recommendations and answers to your questions. And finally, thank you to our sponsors who provided support on behalf of this program activity Amgen, AbbVie, CeraVe, Bristol-Myers Squibb, Jansen and Lilly.

We hope you enjoyed this episode of Psound Bytes for people with psoriasis and psoriatic arthritis. If you or someone you love has ever struggled with psoriatic disease, our hope is that through this series you’ll gain information to help you lead a healthier life and inspire you to look to the future. Please join us for another inspiring podcast. You can find this or all future episodes of Psound Bytes on Apple Podcasts, Spotify, iHeart Radio, Google Play, Gaana, and the National Psoriasis Foundation web page. To learn more about this topic or others please visit psoriasis.org or contact us with your questions or comments by email at podcast@psoriasis.org.  

This transcript has been created by a computer and edited by an NPF Volunteer.

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