Psoriasis: What diet should be adopted to reduce symptoms?

Adopting a healthy and appropriate diet helps individuals with psoriasis to alleviate symptoms. To achieve this, each food contributes its specific effect:

• Foods rich in fibre (brown rice, wholemeal bread, whole wheat, oats) optimise the composition of the gut flora while reducing intestinal permeability. They reduce inflammation by downregulating plasma inflammatory markers such as C-reactive protein (CRP), IL-6, or TNF-α. This is explained by the fact that these dietary fibres, once fermented, produce short-chain fatty acids that promote the activity of T lymphocytes;

• Foods rich in Vitamin B12 (fish/crustaceans): This vitamin suppresses the activation of NF-κB induced by ROS and the NF-κB dependent production of inflammatory cytokines by inactivating the NADPH oxidase;

• Foods containing Vitamin A : Retinoic acid, the most acidic form of Vitamin A, has a beneficial effect in soothing psoriasis. It inhibits the development of Th17 lymphocytes by suppressing IL-6Rα and IL-23R.

The development of psoriasis can be attributed to stress and anxiety. If this is the case for you, foods rich in and containing magnesium are particularly recommended. They help to combat fatigue and fight stress. For instance, whole grains, dried fruits, and chocolate are beneficial to the body.

While some foods can help to curb the development of psoriasis, others can exacerbate the symptoms. Here is a list of foods to avoid if you are prone to this chronic skin disease:

• Gluten

Coeliac disease is an inflammatory enteropathy caused by an immune response to the protein gliadin, found in gluten-containing foods such as wheat. Several studies have reported an association between psoriasis and coeliac disease, including a threefold increased risk of coeliac disease in patients with psoriasis in a 2017 meta-analysis. This correlation may be explained by the fact that Th1 cytokines are involved in the pathogenesis of both conditions. These cytokines tend to produce pro-inflammatory responses.

• Alcohol

Alcohol should be avoided by individuals suffering from psoriasis as it releases pro-inflammatory compounds, known as cytokines. Alcohol also triggers the proliferation of keratinocytes by increasing the levels of integrin α5, KGFR and cyclin D1, which are characteristic transcripts of keratinocytes.

• Sugar

An excessive intake of sugars promotes the differentiation of Th17 lymphocytes by activating TGF-β. This will encourage the production of IL-17 cytokines, one of the main factors causing psoriasis.

• Caffeine

Experiments in rats have demonstrated that caffeine has pro-inflammatory effects when administered during an inflammatory process. It exacerbates tissue damage by amplifying the levels of mRNA of TNF-alpha, TNF-β, lymphotoxin-β, IL-6 and IFN-gamma in the spleen and by increasing IFN-gamma in the blood. Notably, cytokines such as IFN gamma act as mitogens for keratinocytes in psoriasis, promoting their proliferation.

• Saturated fatty acids

Saturated fatty acids induce the NLRP3 inflammasome and IL-23/IL-17. These innate immunity complexes and interleukins trigger a cascade of inflammatory reactions. Red meat, which contains saturated fatty acids, when consumed excessively, could exacerbate psoriasis.