Fat Affects Psoriasis Symptoms (Study Shows Which Diets Help Most)


If you have the skin condition psoriasis, keeping extra pounds off could make a big difference in your symptoms.

If you have psoriasis, you already know that smart lifestyle strategies (such as managing stress, not using harsh soaps, and avoiding certain foods) may help keep symptoms at bay.  UVB phototherapy has has proven to be very effective for preventing and healing psoriasis plaques.

But one of the most important things you can do to keep the skin condition under control might be to shed extra pounds. Here are the reasons why it’s so crucial for psoriasis patients to watch their weight.


Weight Loss Affects Your Psoriasis



Psoriasis is an autoimmune disease, which means the immune system attacks a part of the body (in this case, the skin). The result is raised red, white, or silvery patches on the skin, as well as other possible symptoms such as itching, nail disfigurement, or dry, cracked skin.

Psoriasis is a chronic condition, meaning you have it for your entire life—but weight loss can alleviate some of the symptoms.


Clinical Study



A recent Danish study published in American Journal of Clinical Nutrition, found that obese psoriasis participants who lost 10% to 15% of their body weight showed significant improvement in symptoms.

What’s more, the improvement was long-lasting: a year after the study ended, the participants who lost at least 22 pounds from their start weight continued to experience improved quality of life.

The study participants lost an average of 33 pounds over 16 weeks. A year later, those who were still about 22 pounds below their weight from the start of the study maintained their improvements in psoriasis symptoms and quality of life, the study authors said.

“Psoriasis is more than just a skin condition,” said Dr. Doris Day, a dermatologist at Lenox Hill Hospital in New York City. Increased weight can stress the heart and other organs, and that stress can trigger psoriasis, she said.


Extra Weight Increases Risk of Psoriatic Arthritis



About 10% to 30% of psoriasis patients eventually develop psoriatic arthritis, an autoimmune disease that causes painful, swollen joints. But overweight or obese psoriasis patients seem to be particularly at risk. 

In a study published in the journal Annals of the Rheumatic Diseases, researchers found a link between obesity and increased chance of developing psoriatic arthritis.

The study looked at data collected over a 15-year period of more than 75,000 people in the UK, and found that psoriatic arthritis incidence rates increased along with BMI.


We’re now able to say psoriasis patients have an increased risk of psoriatic arthritis if they are heavy.

– study author Thorvardur Jon Love, MD, assistant professor of rheumatology, Landspitali University Hospital, Reykjavik, Iceland.


“The way we split them up by weight groups gives us a way to say there is a graded effect – the heavier people are, the greater the risk.

“It’s a concern that the percentages are as large as they are and the risk increases as much as it does, especially when you get in the higher weight groups,” Dr. Love says.

The study also found that extra pounds increased the risk of developing psoriatic arthritis even among those who did not have psoriasis.

Researchers say the increased risk could be because fat tissue – also called adipose tissue – overproduces inflammatory cytokines (or proteins) in the body.

“If you are obese, some inflammatory markers are elevated on a daily basis,” Dr. Love explains. “Because of this elevated inflammatory state you find in obese individuals, they may be more sensitive to triggers that lead to arthritis.”


Fat Makes Psoriatic Arthritis Worse



If you’re a psoriasis patient who also has psoriatic arthritis, extra weight can strain your joints, which may aggravate symptoms. Psoriatic arthritis can affect both smaller joints (think: fingers, toes, wrists) as well as large, weight-bearing ones like your knees—and added pounds can put unnecessary pressure on them, making symptoms worse.

“No matter what type of arthritis you have, weight is particularly bad for weight-bearing joints, the hips and knees in particular,” says James R. O’Dell, MD, chief of rheumatology at the University of Nebraska Medical Center in Omaha.

Research backs this up: a 2014 study concluded that:


“Overweight and obese patients with [psoriatic arthritis] are less likely to achieve sustained [remission] compared to those of normal weight.”


This conclusion cannot be overstated; if you have psoriatic arthritis and are overweight, one of the most important steps you can take toward symptom improvement is to lose weight.


Extra Weight Interferes With Psoriasis Medications



One reason why obese psoriatic arthritis patients may be less likely to achieve remission?

Overweight and obese people don’t always respond as well to medications used to treat the disease, according to the Arthritis Foundation.

“You have this perfect storm,” says Dr. O’Dell. “You’re more likely to have problems and to have less response to medication.”

According to a recent study, the heavier people were, the less likely they were to respond to either biologic drugs or traditional disease modifying anti-rheumatic drugs (DMARDs), a result found in a number of earlier studies. Higher weights were also linked to more severe skin problems, worse pain and a higher number of tender joints.

Dr Gladman MD, professor of medicine at the University of Toronto and co-author of the Annals of Rheumatic Disease study says “When you are overweight, it’s difficult to figure out the dose of medication you might need. [Dosing of] Remicade is weight-related, but other drugs don’t have that, so obese patients may be under treated because we don’t know the precise dose we should be using.”


Weight Loss Helps Biologics Work Better



Losing weight may help medications work more effectively for both psoriatic arthritis and psoriasis. In a 2014 study of obese psoriasis patients, researchers found that losing weight helped increase the efficacy of biologic drug treatments.

This is particularly important because, when people have stubborn, widespread, or disabling psoriasis, doctors turn to biologics.  Unlike older prescription drugs made from chemicals, biologics are derived from human or animal proteins, and are very helpful. Delivered by injection (or, in one case, by intravenous infusion), these next-generation treatments target the cells and proteins that cause psoriasis symptoms.

As a treatment for psoriasis, biologics provide “a highly effective, very safe approach,” says Steven Feldman, MD, PhD, professor and director of the Center for Dermatology Research at Wake Forest School of Medicine. With biologics, “we’re closer to treating the underlying cause of the immune imbalance,” he explains. By contrast, older, chemical-based medicines like methotrexate and cyclosporine have broader effects, posing liver or kidney problems, for example, he says.

So if you are on a biologic or considering starting one, and are overweight, you can help this medication work best by dropping extra weight.


Does Obesity Cause Psoriasis?


The Psoriatic March



The “psoriatic march.” Psoriasis and its comorbidities, primarily obesity, contribute to the inflammatory burden of the affected patient. Systemic inflammation in turn causes insulin resistance. This results in endothelial dysfunction, which provides the basis for atherosclerosis and subsequently myocardial infarction (heart attack), if coronary arteries are involved.

Endothelial dysfunction – a condition in which the endothelial layer (the inner lining) of the small arteries fails to function normally.

Atherosclerosis – the narrowing of arteries due to plaque buildup on the artery walls.

Research has found a definite association between being overweight and having psoriasis and psoriatic arthritis, but medical experts continue to study how the two are linked.

The question of which comes first—whether obesity leads to psoriasis or the other way around—is something like the age-old puzzle: Which came first, the chicken or the egg?

“There’s no solid answer,” says Dr. Kristina Callis Duffin, assistant professor of dermatology at the University of Utah School of Medicine in Salt Lake City. “That’s the issue. Nobody knows still.”

But physicians are starting to believe that the connection goes both ways. For instance, recent studies showed that having a high body mass index, or BMI, at an early age is associated with the development of psoriasis later in life, says Dr. Abrar A. Qureshi, vice chairman of dermatology at Boston’s Brigham and Women’s Hospital and an assistant professor at Harvard Medical School. BMI is a measure of one’s body-fat content, a way to estimate whether a person is an appropriate weight based on height.

Likewise, “There are studies showing that people (with psoriasis) don’t exercise or eat as well, because they don’t feel good about their bodies,” Duffin points out. Some studies have found that patients gain weight after the onset of psoriasis. Explanations proposed for this relationship include increased social isolation, unhealthful dietary habits, depression and alcohol consumption, as well as decreased physical activity, particularly after developing psoriatic arthritis.

By the same token, there also is strong evidence that obesity predisposes individuals to the development of psoriasis. A large study of female nurses—78,626 total women, 892 of whom self-reported having psoriasis—found that weight gain placed individuals at an increased risk for the subsequent development of psoriasis.

In addition, Qureshi says, researchers have observed that the severity of psoriasis is linked with being more obese; that is, patients with the most severe psoriasis tended to have higher BMIs. Obesity is defined as a BMI of 30 or higher, whereas morbid obesity is a BMI of 35 or more.

Utah researchers looked at the risk of psoriatic arthritis among 943 patients with psoriasis.

Among their findings:

  • At the age of 18, 14 percent of the patients were classified as overweight and 5 percent as obese.
  • A total of 250 patients went on to develop psoriatic arthritis and analysis showed that the risk of developing the condition was higher among psoriasis patients who were overweight at age 18, and even more so for those who were obese.

Duffin notes that psoriasis patients who were overweight or obese developed psoriatic arthritis earlier than psoriasis patients of a healthy weight.


It’s All About Inflammation


Obesity Causes Inflammation


Doctors now understand that:

  • psoriasis and psoriatic arthritis are inflammatory diseases, and
  • obesity is associated with inflammation.

These connections help explain how obese patients may be predisposed to the development of psoriasis.



Inflammatory Diseases


Researchers think that as increased body fat is associated with higher levels of inflammatory cytokines known to be involved in psoriasis, this “inflammatory milieu” could increase the risk of psoriatic arthritis. “I always called cytokines ‘the cheerleaders of inflammation,’ ” Duffin says. “If you have more of these substances, you are more at risk of developing psoriasis.”

Obese patients can be harder to treat effectively.


A study by the National Psoriasis Foundation Medical Board, published in 2010 in the Journal of the American Academy of Dermatology, states that:


When compared with psoriasis patients who are not overweight, obese patients with psoriasis are more likely to experience certain adverse effects to medications and are less likely to respond favorably to systemic therapies.


Qureshi and Duffin advise dermatologists and rheumatologists to discuss the risks of being overweight with their patients. “Certainly it behooves us to counsel (patients) about diet and exercise,” Qureshi says, adding that we now know psoriasis and psoriatic arthritis patients are more prone to related health problems such as high blood pressure, diabetes and cardiovascular disease—all of which are more prevalent in obese people.

“It’s important to try to maintain a healthy body weight,” Duffin adds. “You want to lose weight, because you want to prevent these other (serious diseases).” Referrals to a dietitian may be appropriate. Weight loss, she says, is “best done under the supervision of a primary care physician.”


Finding Relief and Weight Loss Through Diet



Psoriasis Patients’ Dietary Habits

Last year, a team of researchers from the University of California-San Francisco (UCSF) School of Medicine’s Department of Dermatology published the results of a national survey designed to gauge the influence of diet on psoriasis. More than 1,200 members of the National Psoriasis Foundation responded to the survey’s 61 questions, with revealing and even surprising results.

Published in Dermatologic Therapy in May 2017, the survey findings offer a vivid picture of patients’ dietary practices, along with foods that seem to intensify their psoriatic skin symptoms and those that quell them. 

The researchers found that people with psoriasis consume less sugar, dairy and whole grain fiber than people who don’t have the disease. More than half of the survey participants reported that reducing alcohol, gluten, and nightshades – members of the plant family that includes tomatoes, potatoes, eggplant and peppers – led to noticeable improvement in their symptoms. Adding fish oil, vegetables, and vitamin D proved helpful as well.


Special Diets Respondents Found Particularly Effective


The Pagano Diet

(based on the principle that psoriasis is caused by a toxic buildup or “leaky gut”)


Healing Psoriasis by John Pagano



The Vegan Diet




Bestseller: The Mediterranean Diet Weight Loss Solution


The Vegetarian Diet


Example: Living Vegetarian for Dummies


John Y.M. Koo, M.D., director of the Psoriasis, Phototherapy and Skin Treatment Clinic at UCSF and a co-author of the study, noted that the common thread running through these very different diets is that they lead to weight loss. 

“The evidence may not yet be available regarding which of these diets is most effective for psoriasis patients, but one thing has been observed to be of universal benefit: losing weight,” Koo says. “To the extent that the Paleo or vegan or gluten-free diet helps people do that, they’re worth trying.”

The data gleaned from the survey aren’t evidence in the strict sense, says Koo. Nonetheless, he believes the results are meaningful.


“Because the survey is based on reports from real life – on what’s working for patients and what isn’t – the findings can be empowering for them,” he says. “Patients can decide to eliminate one of the triggers on the list or follow one of the top-ranked diets in the survey and track their response over time.”


To do that, people should keep a food journal, commit to a trial-and-error approach, and “remain open-minded and aware that what works for one person may not work for another,” says Wilson Liao, M.D., the study’s senior author. “They should also consider working with a nutritionist, or a physician with a strong background in nutrition, to design a suitable diet in light of the individual’s preferences and medical history.” 


Final Thoughts

It is well recognized that being overweight is a risk factor for the development of psoriasis and psoriatic arthritis. There is also evidence to show that being overweight reduces the therapeutic benefit of many of the medications used in treating psoriasis.

In other words, if you are overweight you are more likely to have psoriasis, more likely to develop or worsen psoriatic arthritis, and the medications used in treatment will be less effective.

Let me know your thoughts.

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