Psoriasis and diet?

Author: 

Micaela Karlsen, MSPH

Question: 

I'm curious if there is any news/updates on how nutrition affects psoriasis? Doctors always want to give topical treatment, but that doesn't address inflammation inside the body. I am interested to know if there is some nutritional or supplemental answer: I have heard about silymarin or milk thistle.

Answer: 

Psoriasis is the most common autoimmune disease in the U.S. As many as 7.5 million Americans have psoriasis, according to the National Psoriasis Foundation. Psoriasis is an autoimmune disease in which the skin cell production is accelerated, most commonly resulting in red skin patches covered with silvery layers of dead skin cells. Itching and pain often accompany the condition.

Psoriasis tends to be associated with metabolic syndrome and aggravated by overweight and obesity, especially for those who have the condition in skin folds which tends to rub and irritate the skin further. This clinical trial,  Effect of weight loss on the severity of psoriasis: a randomized clinical study., demonstrated a reduction in severity and quality of life with weight loss. At the same time, this study Weight reduction alone may not be sufficient to maintain disease remission in obese patients with psoriasis: a randomized, investigator-blinded study., showed that weight loss alone may not be enough.

An analysis of the National Health and Nutrition Examination Survey (NHANES) data in the United States showed several significant associations with sugar consumption and certain nutrients.

However, interestingly an intervention using a controlled fast followed by adoption of a vegan diet showed an improvement both during the fast and afterwards while eating the prescribed diet. The TrueNorth Health Center, which offers water-only fasting in Santa Rosa, CA, frequently does have psoriasis patients who improve during a fast and eating the very low-fat, no added salt, whole food, plant-based diet served there. While none of the results are published, some patients have posted their anecdotal evidence on YouTube.

This Pilot study on which foods should be avoided by patients with psoriasis found significant reductions in symptoms by reducing beef, caffeine, and MSG, among other things. This paper also contains a discussion of the possible mechanisms for each of the foods or substances examined.

Very limited information exists on silymarin and psoriasis - a PubMed search reveals only 1 paper, a review in the Alternative Medicine Review, Silybum marianum (Milk Thistle), in which psoriasis is briefly mentioned.