Medical nutrition therapy as a potential complementary treatment for psoriasis—five case reports

Alternative Medicine Review, Sept, 2004 by Amy C. Brown, Michelle Hairfield, Douglas G. Richards, David L. McMillin, Eric A. Mein, Carl D. Nelson

Introduction

Psoriasis is a chronic, inflammatory skin disease characterized by thickened, silvery-scaled patches. (1) Its cause is not yet known, but numerous studies link it with inflammatory and immune mechanisms most likely associated with a genetic predisposition that can be triggered by stress. (2)

Because there is no cure for psoriasis, the multiple treatment options currently available only attempt to reduce the severity of symptoms. Non-pharmacological therapies include sunlight and stress avoidance, while pharmacological treatments are either topically applied in the form of creams or lotions, orally ingested, or injected. Most patients are treated with topical therapies sometimes combined with phototherapy and/or systemic medications.

Topical applications include:

* Anthralin--A synthetic substance made from a coal tar derivative used since the 19th century; however, it is a highly irritating substance that needs to be thoroughly washed off after each session.

* Calcipotriol--A synthetic form of vitamin [D.sub.3] that inhibits cell proliferation but may elevate serum calcium.

* Corticosteroid treatment--Common steroids such as Diprolene, Psorcon, Temovate, and Ultravate improve psoriatic lesions, but side effects include skin thinning, hair follicle infections, facial redness, rosacea, a worsening of diabetes mellitus, and reduced endogenous steroid production.

* Topical retinoids--Some patients experience partial clearing of psoriasis with topical retinoids, but often abandon therapy due to skin reddening and irritation.

* Topical Tacrolimus and Pimecrolimus--These topical treatments represent a new class of nonsteroidal topical immunomodulators; however, only a few studies have been performed and side effects include a burning sensation.

Oral medications are usually reserved for severe psoriasis cases because of potentially serious side effects. Among the systemic therapies associated with significant side effects are acitretin, methotrexate, cyclosporine, hydroxyurea, and thioguanine. Individuals on these medications must be closely monitored and the medications cannot be used for long-term treatment. (3) Other systemic therapies include monoclonal antibodies, (4) protein specifically targeting memory T cells, (5) fumaric acid esters, (6) novel retinoids, and macrolactams. (7) In addition to potential side effects, current oral and topical treatments are often only a partial or temporary solution.

Annual medical treatment costs for psoriasis in the United States are estimated at approximately $1.6-3.2 billion. The need exists for more effective treatment options with fewer side effects.

One such option is medical nutritional therapy. Although the American Dietetic Association promotes no specific diet for psoriasis, researchers have reported the effect on psoriasis of modifying various aspects of the diet. Strong scientific evidence exists for a gluten-free diet; (8-9) some scientific evidence exists for a vegan diet, (10) rice diet, (11) and supplementation with fish oil (12) and vitamin D; (13) and weak scientific evidence exists for a low protein diet, (14) fasting/starvation, (15) and supplementation with evening primrose oil, (16) taurine, (17) and zinc sulfate. (18-19)

Psoriasis patients showed significant improvement after six months when fed a gluten-free diet. (8) Naldi et al and Kavli et al noted in epidemiological studies that increased intake of fresh fruits and vegetables is linked with a decreased prevalence of psoriasis. (20,21) Pagano published a book for the general public (partially based on Edgar Cayce's readings) describing a diet composed primarily of fresh fruits and vegetables, with small amounts of fish, fowl, and lamb. (22)

The present study explores the effectiveness of a treatment protocol, based on Edgar Cayce's readings on psoriasis, that includes a dietary regimen, herbal supplements, and addressing intestinal permeability. Several lines of research support this systemic approach. Comorbidity studies link intestinal pathology with a variety of skin conditions, including psoriasis. (23-25)

Although there is evidence in cases of psoriasis for structural abnormalities in the intestine, (26-28) the data specifically linking intestinal permeability to psoriasis is mixed. Humbert et al compared intestinal permeability of psoriasis patients with healthy controls using the [sup.51]Cr-labeled EDTA absorption test, and found the psoriasis group had significantly increased bowel permeability. (29) On the other hand, Hamilton et al used the cellobiose/mannitol differential sugar absorption test, and although these latter researchers found an abnormal recovery ratio in seven of 29 psoriasis patients, they concluded this rate was similar to a control population. (30) The present study continues to explore this question.

The concept of increased intestinal permeability as a cause of psoriasis is based on the premise that substances from the diet larger than those normally absorbed can enter the circulation and initiate an immune system response resulting in psoriatic lesions. Until the early 20th century, "autointoxication" was widely accepted and various therapies (such as colonic irrigation) were commonly used for a variety of systemic disorders. Unsupported by scientific evidence, autointoxication tell out of favor several decades ago. (31) However, the growing body of information linking intestinal disease, excessive intestinal permeability, and systemic illness has revived the theory. (32,33) The concept of autointoxication gains support from several case studies suggesting hemodialysis and peritoneal dialysis are effective in the treatment of psoriasis. (34-37)