The effects of turmeric on psoriasis?

The psoriasis is a chronic inflammatory skin condition that can appear on various areas of the body, such as the scalp, soles of the feet, elbows... It presents itself as red and thick plaques that flake. Psoriasis is characterised by an excessive renewal and accumulation of the cells of the epidermis, leading to a local inflammation. This disease tends to affect adults, with a peak onset generally between 20 and 40 years of age.

The cause of psoriasis is predominantly genetic. Indeed, 30% of cases correspond to familial forms involving genetic predispositions. The major gene implicated is the PSORS1 locus. Other minor genes also play a role. The genetic variants associated with psoriasis are located in the genes involved in immunity, which leads to an immune system imbalance causing chronic skin inflammation and an overproduction of keratinocytes.

We note other causes, this time extrinsic, that promote the development of psoriasis. Thus, medications, certain streptococcal infections, stress, cellular oxidants or lifestyle (alcohol, tobacco...) can trigger or worsen psoriasis. It's also worth noting that this disease does not only affect the skin. About a quarter of people suffering from psoriasis experience joint pain: this is referred to as psoriatic arthritis. Finally, this disease has a strong psychological impact and can affect quality of life (sleep disorders, social withdrawal, irritability, depressive syndrome...). That's why it's important to manage it as early as possible.

The turmeric is among the most acclaimed natural alternative solutions for targeting psoriasis. Whether it is added to the diet or used as a mask or cream, it possesses anti-inflammatory and healing properties. These various properties are primarily derived from the curcumin it contains.

This molecule also has the ability to limit the proliferation of keratinocytes, which is excessive in individuals suffering from psoriasis. This is due to its ability to prevent the synthesis of certain pro-inflammatory cytokines, such as interleukins 1α and 6 (IL-1α and IL-6). In addition to playing a role in the immune response, these cytokines act as a growth factor for keratinocytes. Their inhibition therefore allows for a reduction in keratinisation. Furthermore, curcumin inhibits the production of prostaglandins, inflammatory molecules, which allows to reduce pain sensitivity.

One of the differences between the epidermis of a person suffering from psoriasis and that of a person not suffering from it is the level of expression of the enzyme phosphorylase kinase (PK). This protein normally regulates the processes of glycogenolysis and phosphorylation, but overactivity is associated with the symptoms of psoriasis. However, curcumin is a selective inhibitor of phosphorylase kinase and can reduce the expression of this protein and bring it back to normal levels. A study has notably shown that the daily application for 4 weeks of a cream with 1% curcumin could reduce the activity of PK by 85%. Given that the proportion of curcumin in turmeric powder is about 10%, it can be assumed that this ingredient has similar properties.

Finally, the healing power of curcumin has been demonstrated in several studies. This molecule notably accelerates epithelialisation and angiogenesis, the synthesis of new blood vessels, by increasing the expression of the growth factor TGF-β1. Furthermore, curcumin prevents the depletion of glutathione, an antioxidant, and limits lipid peroxidation. This protects the cells of the epidermis and dermis, resulting in a better migration of fibroblasts at the wound site. It is also worth noting that curcumin inhibits the activity of matrix metalloproteinase-2 (MMP-2). This is a complex that triggers the synthesis of an enzyme whose role is to degrade collagen. By ensuring better stability for the latter, turmeric once again promotes epithelialisation.

Note : If you are suffering from psoriasis, we advise you to consult with a general practitioner or a dermatologist who will guide you towards a comprehensive treatment, as turmeric can only be used as a supplement.

• SUDHEER A. & al. Antioxidant and anti-inflammatory properties of curcumin. Advances in Experimental Medicine and Biology (2007).

• MAHESHWARI K. & al. Beneficial role of curcumin in skin diseases. Advances in Experimental Medicine and Biology (2007).