A simple modification in this diet improves psoriasis skin and reduces joint inflammation.
A high-sugar and moderate-fat diet such as the Western diet can upset the gut microbiota leading to joint inflammation and inflammatory skin disease.
However, according to a study, a simple diet modification of less fat and less sugar will restore gut health and lower inflammation.
Professor Sam Hwang, the study’s senior author, said:
“Earlier studies have shown that 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.”
Psoriasis is an immune system disorder in which immune cells mistakenly attack skin cells causing inflammation and red itchy scaly patches of skin.
Nearly one third of people with psoriasis suffer from psoriatic arthritis, showing symptoms such as fatigue, morning stiffness, joint pain, swollen fingers or toes, changes in the nails, and lower back pain.
Modern dietary patterns such as the Western diet appear to have a direct impact on skin inflammation by changing the gut microbial balance.
A Western-style diet is generally high in sugar and fat, which both have a harmful effect on the microbial community and their function leading to gut dysbiosis and so inflammatory diseases.
The study tested if gut dysbiosis can lead to skin and joint inflammation.
They injected interleukin-23 minicircles in mice to produce an immune response that looked like psoriatic arthritis.
Interleukin-23 is secreted by the inflammatory immune cells accountable for conditions such as inflammatory bowel disease (IBD) and psoriasis.
The research team noticed that consuming a Western diet, even for a short period of time, causes microbial imbalance and increases the levels of interleukin-23-mediated psoriasis.
Professor Hwang said:
“There is a clear link between skin inflammation and changes in the gut microbiome due to food intake.
The bacterial balance in the gut disrupted shortly after starting a Western diet, and worsened psoriatic skin and joint inflammation.”
The team then wanted to see if the gut microbiota can be restored by changing to a balanced diet.
For six weeks, mice were fed a Western diet and then an interleukin-23-inducing agent to set off psoriatic skin and joint inflammation.
Later, the mice were divided into two groups; one continuously received the diet for one more month and the second group was fed with a balanced diet instead.
Ten weeks eating a Western diet caused skin and joint inflammation in mice, whereas shifting to a balanced diet reduced scaling skin in the second group.
This indicates that reducing sugar and fat intakes can lower the pro-inflammatory response and gut microbiota alteration (dysbiosis).
Dr Zhenrui Shi, the study’s first author, said:
“It was quite surprising that a simple diet modification of less sugar and fat may have significant effects on psoriasis.
These findings reveal that patients with psoriatic skin and joint disease should consider changing to a healthier dietary pattern.”
The study was published in the Journal of Investigative Dermatology (Shi et al., 2021).
