Psoriasis is a chronic autoimmune skin condition that affects millions of people worldwide. It causes skin cells to multiply rapidly, leading to a buildup of scaly, inflamed patches. Psoriasis is associated with an overactive immune system, which mistakenly attacks healthy skin cells. This causes skin inflammation, redness, itching, and scaling.

While there is no cure for psoriasis, treatments such as topical creams, phototherapy, and oral medications can help manage symptoms and prevent complications. However, researchers are also exploring other potential factors that may contribute to psoriasis and its associated symptoms, such as diet and gut health.

A new study published in the Journal of Investigative Dermatology has found that a diet rich in sugar and fat leads to an imbalance in the gut’s microbial culture and may contribute to inflammatory skin diseases such as psoriasis. The study suggests that switching to a more balanced diet restores the gut’s health and suppresses skin inflammation.

According to the senior author of the study, Professor Sam T. Hwang, “There is a clear link between skin inflammation and changes in the gut microbiome due to food intake. Earlier studies have shown that a Western diet, characterized by its high sugar and fat content, can lead to significant skin inflammation and psoriasis flares. Despite having powerful anti-inflammatory drugs for the skin condition, our study indicates that simple changes in diet may also have significant effects on psoriasis.”

Food is one of the major modifiable factors regulating the gut microbiota, the community of microorganisms living in the intestines. Eating a Western diet can cause rapid changes to the gut’s microbial community and its functions. This disruption in microbial balance, known as dysbiosis, contributes to gut inflammation.

Since bacteria in the gut may play key roles in shaping inflammation, the researchers wanted to test whether intestinal dysbiosis affects skin and joint inflammation. They used a mouse model to study the effect of diet on psoriasis and psoriatic arthritis. They injected mice with Interleukin-23 (IL-23) minicircle DNA to induce a response mimicking psoriasis-like skin and joint diseases.

IL-23 is a protein generated by the immune cells responsible for many inflammatory autoimmune reactions, including psoriasis and inflammatory bowel disease (IBD).

Hwang and his colleagues found that a short-term Western diet appears sufficient to cause microbial imbalance and to enhance susceptibility to IL-23-mediated psoriasis-like skin inflammation.

“There is a clear link between skin inflammation and changes in the gut microbiome due to food intake. The bacterial balance in the gut is disrupted shortly after starting a Western diet, and worsened psoriatic skin and joint inflammation,” says Hwang.

One critical finding of their work was identifying the intestinal microbiota as a pathogenic link between diet and the displays of psoriatic inflammation. The study also found that antibiotics block the effects of the Western diet, reducing skin and joint inflammation.

The researchers wanted to test if switching to a balanced diet can restore the gut microbiota, despite the presence of IL-23 inflammatory proteins. They fed mice a Western diet for six weeks before giving them an IL-23-inducing agent to trigger psoriasis and psoriatic arthritis features. Then, they randomly divided the mice into two groups: a group that continued the Western diet for another four weeks and a group that switched to a balanced diet for the same duration.

Their study showed that eating a diet high in sugar and fat for 10 weeks predisposed mice to skin and joint inflammation. Mice that were switched to a balanced diet had less scaling of the skin and reduced ear thickness than mice on a Western diet. The improvement in skin inflammation for mice taken off the Western diet indicates a short-term impact of the Western diet on skin inflammation.

Treatment Options

While psoriasis has no cure, several treatment options can manage its symptoms. Doctors often prescribe topical treatments, such as corticosteroids, retinoids, and vitamin D analogs, to reduce inflammation and control the overproduction of skin cells. Phototherapy, which uses ultraviolet light to slow the growth of skin cells, is another option.

For more severe cases, doctors may recommend systemic medications that affect the immune system, such as methotrexate, cyclosporine, or biologic drugs, which target specific immune cells and proteins involved in inflammation.

However, these medications can have significant side effects and may increase the risk of infections, liver and kidney damage, and cancer.

In recent years, several new drugs have emerged that offer safer and more effective treatment options for psoriasis. These drugs, such as secukinumab and ixekizumab, target specific proteins that play a role in inflammation and have fewer side effects than older systemic medications.

Lifestyle Changes

Apart from medications, lifestyle changes can also help manage psoriasis symptoms. Maintaining a healthy weight, avoiding smoking and alcohol consumption, and reducing stress can all improve the condition. In addition, regular exercise and a healthy diet can help reduce inflammation and improve overall health.

As the recent study by UC Davis researchers suggests, a balanced diet that is low in sugar and fat can have significant effects on psoriasis symptoms. It can restore the gut’s health and suppress skin inflammation, thus reducing the need for medications and improving patients’ quality of life.

Future Research

While the study sheds new light on the link between diet, gut health, and psoriasis, more research is needed to fully understand the mechanisms behind this relationship. For example, it is still unclear how a Western diet affects the gut microbiota and how a balanced diet can restore its balance.

Further studies should also investigate whether other dietary modifications, such as increasing fiber intake or consuming probiotics, can improve psoriasis symptoms.

In addition, researchers should explore how the gut microbiota affects other inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease, and multiple sclerosis. Understanding these connections could lead to new treatments and preventive measures for these conditions.


Psoriasis is a common and chronic skin condition that affects millions of people worldwide. While its exact causes are still unknown, researchers have identified several risk factors, including genetics, immune system dysfunction, and environmental factors.

Recent studies have shown that a Western diet, which is high in sugar and fat, can disrupt the gut microbiota’s balance and contribute to inflammation in the skin and joints. On the other hand, a balanced diet that is low in sugar and fat can restore the gut’s health and reduce psoriasis symptoms.

While psoriasis has no cure, several treatment options can manage its symptoms, including topical treatments, phototherapy, systemic medications, and newer biologic drugs. Lifestyle changes, such as maintaining a healthy weight, reducing stress, and avoiding smoking and alcohol consumption, can also help.

As researchers continue to investigate the links between diet, gut health, and psoriasis, new treatment options and preventive measures may emerge. In the meantime, patients with psoriasis should work with their doctors to develop a treatment plan that best suits their individual needs and lifestyle.