If you have an autoimmune disease such as psoriasis or arthritis, diet can have a profound impact on the degree of inflammation and therefore the severity of your symptoms. This is because food impacts the immune system in a variety of ways, including:
- Altering the production of inflammatory mediators
- Directly activating cells of the immune system through allergies or hypersensitivities.
- Influencing the balance of species in the microbiome
- Damaging or preserving the gut barrier
The Keystone Diet is a specialized version of the Mediterranean diet, specifically designed to reduce the inflammation involved in psoriasis and arthritis. There are two levels to the Keystone Diet:
The first level is the basic Autoimmune Mediterranean framework, which is like a standard Mediterranean diet but modified to remove low-nutrient foods that damage the gut and activate immune system (such as refined oils and certain grains and legumes). The basic Autoimmune Mediterranean diet also emphasizes foods shown in clinical trials to reduce inflammation in psoriasis and arthritis (such as fish, olive oil, and the fruits and vegetables that are highest in fiber and antioxidants).
The second level is the Keystone Elimination Diet. This builds on the foundation of Autoimmune Mediterranean diet with an aggressive short-term elimination diet to identify any specific food sensitivities or triggers. This elimination diet is broken into three categories, but for quickest results all three categories are eliminated simultaneously. The three categories are:
- Sugar and starch
- Common food allergens
- Nightshades (tomatoes, potatoes, peppers, etc.)
Of these categories, the elimination of sugar and starch is the most difficult but also the most important to test. The no-starch diet has long been used by many with ankylosing spondylitis, but in 2016 and 2017 a new body of scientific research has shown that eliminating sugar and starch can dramatically reduce gut inflammation and help to restore the balance of the microbiome. This approach will not help everyone, but some remarkable results have been reported. Given the latest findings that gut inflammation and disruptions to the microbiome play a role in psoriasis and many forms of arthritis, a short-term no-starch diet is worth attempting if you have:
- Psoriasis
- Psoriatic arthritis
- Rheumatoid arthritis
- Juvenile arthritis (particularly ERA)
- Ankylosing spondylitis
- Undifferentiated spondyloarthritis
- Joint pain associated with Crohn’s or ulcerative colitis.
For more on the theories behind the Keystone Diet:
The Keystone Approach 