Psoriasis Resource Center

The Mediterranean diet’s protective effects against psoriasis

Researchers have given us plenty of reasons to think that there might be some sort of connection between diet and psoriasis. A wide variety of studies have shown that the immune system can be influenced by environmental factors, including dietary ones. Epidemiologists have added to the pile of evidence findings that link diets with “proinflammatory ”nutrients—saturated fatty acids, heme, iron—to inflammatory conditions such as psoriasis, including inflammatory bowel disease and rheumatoid arthritis.

And on the flip side of this coin, a not-small body of research suggests that diets rich in nutrients with anti-inflammatory properties—dietary fiber, some polyphenols—may lead to lower rates of conditions that are increasingly seen as manifestations (at least in part) of systemic inflammation—conditions such as metabolic syndrome and cardiovascular disease. The Mediterranean diet—with all of its fruits and vegetables, nuts, and extra-virgin olive oil—is a prime example of a diet rich in these anti-inflammatory nutrients.

So it makes sense that researchers would be looking into whether the Mediterranean diet might have some protective effect against psoriasis—either preventing it in the first place or reducing its severity after occurs.

A study published in the September 2018 issue of JAMA Dermatology takes just such a look. It would be jumping the gun to say the Mediterranean diet has an anti-psoriatic effect, but the findings from this study are solidly suggestive that it might.

Céline Phan, MD, at the Mondor Hospital in suburban Paris and her colleagues used data from the NutriNet-Santé program, an observational, web-based epidemiologic study that includes about 160,000 people. With an online questionnaire, they identified 3,557 of the study participants as having psoriasis, of whom 878 had severe cases. They then looked at their answers to dietary questionnaires and categorized them according to how adherent they are to a Mediterranean diet. The “MEDI-LITE” scores ranged from zero (no adherence) to 18 (full adherence).

The takeaway finding from Phan et al. is that there is, in fact, evidence of an association between severe psoriasis and diets that stray from the Mediterranean diet. More specifically, they found that almost half (46%) of patients with severe psoriasis had a MEDI-LITE score in the very low, 0–7 range compared with a just over a third (36%) of patients with a nonsevere case or no psoriasis at all. They also tested whether the association was still there after adjusting for confounding factors such as being overweight, having diabetes, and so on. Most of those statistical models showed that the relationship was, in fact, still there.

As researchers, Phan et al. need to be cautious. They make a point of saying that more studies need to be done before there’s certainty about the relationship between Mediterranean diets and psoriasis.

But say those studies are done, and say they produce similar results. Then, wrote Phan and her colleagues, an “optimized diet” should be part of the how the disease of people with psoriasis is be managed.

Till then, though, this study would seem to put a Mediterranean diet into that the big category of could-help, can’t-hurt for psoriasis and many other inflammatory conditions. 

Pass the olive oil, please.