Editors note: This information is provided for educational purposes. It is not meant to diagnose or treat any condition. If you have skin lesions or any health issue, consult a licensed healthcare practitioner in person.
Psoriasis is complex to treat.
In fact, Physician Paul Bechet once said its the antidote to a dermatologists ego (1).
Its an autoimmune disease that causes chronic pain and itching that can severely impact on quality of life.
Many foods and supplements are rumored to help with psoriasis treatment. But does research support these claims?
This article examines the evidence surrounding the relationship between diet and psoriasis.
Psoriasisis a chronic autoimmune disease that causes patches of skin to become inflamed and scaly.
It affects up to 4% of the worlds population (2).
Symptoms occur in flares, and include itching, pain, and skin lesions. Psoriasis may also cause pitted fingernails and toenails, as well as mouth sores.
There are sixtypesof psoriasis. Each type causes a distinctive rash:
Plaque psoriasis.Image source.
Guttate psoriasis.Image source.
Inverse psoriasis.Image source.
Pustular psoriasis.Image source.
Erythrodermic psoriasis.Image source.
Summary:Psoriasis is a chronic condition that causes distinctive skin rashes, itching, inflammation, and pain. Symptoms occur in flares.
Psoriasis is caused by a combination of genetic, environmental, and immunological factors (3).
One large study found that a persons risk increases up to 65% if their parents have psoriasis, and up to 83% if both their parents and siblings have it (4).
Not everyone who carries the gene will develop psoriasis. However, exposure to certain environmental stimuli may increase a persons likelihood of developing the disease.
These stimuli include:
In the presence of both environmental and genetic factors, the immune system malfunctions.
T cells, which normally respond to infection and injury, are mistakenly activated as a result. These cells recruit other immune cells and trigger the release of inflammatorycytokines(13).
This causes the skin cells to die off and regenerate more quickly than they should.
Onset of psoriasis.Image source. Click to enlarge.
The same environmental factors that cause psoriasis can also lead to flares, so its best to limit exposure to them when possible.
Summary:Psoriasis occurs when the immune system mistakenly attacks healthy skin cells. Many people carry a gene for the disease and develop it after exposure to certain environmental factors.
The standardtreatmentsfor psoriasis involve topical and oral medications, as well as ultraviolet light therapy.
There is no scientific proof that diet is an effective treatment for psoriasis on its own.
However, patient testimonials and studies have shown certain diet strategies may help relieve psoriasis symptoms, especially when combined with traditional therapies.
The following sections will focus on foods and nutrients that affect psoriasis severity.
Overweight (in a clinical setting) is characterized by a body mass index (BMI) greater than 24.9.
A BMI greater than 29.9 is classified as obese.
Many studies have found a possible link between obesity and psoriasis.
In one long-term study of more than 67,000 females (14):
Even weight gain of just 10 pounds (4.5 kg) appears to increase risk by up to 8%, regardless of BMI classification (15).
In addition to risk, obesity is also linked to disease severity. This is likely because excessive fat tissue increases production of inflammatory cytokines, which contribute to inflammation and lesions in psoriasis (16,17).
It makes sense then that studies have shown that calorie restriction paired with medication is more effective in reducing psoriasis symptoms than medication alone (18).
Notably, most studies on obesity and psoriasis are observational. This means that researchers arent exactly sure if obesity causes the disease or vice versa.
In any case, psoriasis is linked with several other heart disease risk factors, including high cholesterol, diabetes, and high blood pressure.
Weight loss can reduce heart disease risk for people who are overweight or obese, so it makes sense to maintain a healthy weight (17).
You can calculate your BMIhere.
Summary:Those who are very overweight are more likely to have psoriasis, although researchers arent sure if obesity causes it directly. Maintaining a healthy bodyweight also lowers risk of heart disease which is more common in psoriasis patients.
The autoimmune protocol(AIP) is a diet that eliminates gluten, soy, dairy, legumes, grains, added sugars, nightshades, and alcohol for at least 30 days.
The goal is to identify foods that trigger undesirable autoimmune reactions.
Theres a strong link between psoriasis and other autoimmune diseases. In one large study, those with psoriasis had higher rates of 14 different autoimmune disease than the general population (19).
Patient testimonials suggest that the AIP is helpful for many conditions, including psoriasis.
There have been no clinical trials on the AIP, so theres no scientific evidence to support it. But certain foods eliminated in the AIPincluding gluten and alcoholhave been reported to worsen psoriasis symptoms.
Some small studies have shown a gluten-free diet to improve psoriasis symptoms, but only in those with antibodies againstgliadin(a protein found in gluten). These antibodies would be seen in those with celiac disease or non-celiac gluten sensitivity (20).
Although other studies found no benefits at all, so its all quite unclear at this stage (19).
A stronger link has been suggested between alcohol intake and psoriasis severity.
One review of 28 studies found that alcohol is likely a risk factor for developing psoriasis, and that those with the disease drink more than healthy adults (11).
Its best to avoid alcohol if you have psoriasis, or a strong family history of it.
Summary:Patient testimonials suggest that the autoimmune protocol may help with psoriasis, but this hasnt been formally studied. You should definitely avoid alcohol and potentially gluten too if you are sensitive.
A Western diet high in fat, sodium, and added sugars has been linked to inflammation and autoimmune disease (21).
For this reason a so-called anti-inflammatory diet may ease psoriasis symptoms.
Theres no universal definition for anti-inflammatory diet, but it generally refers to a style of eating that (22,23,24):
An anti-inflammatory diet hasnt been studied in psoriasis specifically, but systemic inflammation is a key feature of the disease.
This diet pattern has also been shown to help with certain autoimmune diseases, so in theory and based on patient testimonials it may be beneficial (18,25,26).
Patient testimonials also indicate that an anti-inflammatory eating pattern is helpful for arthritis. As such, it may be useful for relieving pain and stiffness in thosewith psoriatic arthritis(27,28).
The diet is similar in many ways to the Mediterranean diet, which includes fish and lean meats, vegetables, fruits, healthy fats, whole grains, and legumes.
In one study, stronger adherence to the Mediterranean diet was associated with fewer psoriasis symptoms. Further, those with fewer symptoms ate more fruit, vegetables, legumes, nuts, and fish and less meat (29).
More human studies are needed to know if the Mediterranean diet is beneficial for psoriasis. But given itsother health benefits, such as reducing heart disease risk, it makes sense to eat this way regardless of its effects on skin (30).
Summary:Anti-inflammatory and Mediterranean diets emphasize healthy fats, fruits, vegetables, and whole grains. One study linked the Mediterranean diet with improved psoriasis symptoms.
Several dietary supplements have been reported tohelp with psoriasis treatment.
Fish oil capsules contain the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexanoic acid (DHA).
Its known for its anti-inflammatory properties.
In one literature review, 12 of 15 studies found fish oil to improve psoriasis severity (31).
The strongest evidence is in support of high-dose intravenous (IV) omega-3 infusions for plaque and guttate psoriasis. However, this isnt a typical therapy, and wouldnt be readily available to most patients (32,33).
One small observational study found that oral fish oil supplements significantly reduced psoriasis severity and improved quality of life when paired with prescription ointment. Volunteers in this study received 640 mg of DHA plus EPA per day for eight weeks (34).
Change in Psoriasis Area and Severity Index (PASI) overdurationof study for fish oil plus ointment group compared to ointment only group.Lowerscore is better. Click to enlarge.
Larger clinical trials are needed to confirm these effects but it looks promising.
Probioticsare beneficial bacteria that we eat.
They have been the focus of many studies recently because of the interaction between the gutmicrobiomeand various health conditions, including psoriasis.
One study found adults with psoriasisespecially psoriatic arthritisto have less diversity in gut bacteria than healthy adults. The researchers likened the bacterial profile in psoriasis to that of inflammatory bowel disease, which often responds well to probiotics (35,36).
In another study, 23 patients with mild to moderate plaque psoriasis received the probioticBifidobacterium infantis35264 at a dose of 11010colony forming units (CFU) per day for eight weeks.
Researchers found that most blood markers of inflammation (CRP and TNF-) were significantly lower at eight weeks (37).
Other probiotic strains havent been studied specifically in psoriasis yet.
Vitamin D helps regulate the immune system by inhibiting T cell multiplication and limiting cytokine production (38).
Because T cells and cytokines play key roles in psoriasis, and because vitamin D deficiency is common among those with autoimmune disease, its been studied as a possible psoriasis treatment (38).
One literature review found vitamin D supplements and ointments to be as effective as corticosteroids in easing symptoms. The benefits were even greater when vitamin D was used with a high-dose steroid ointment (39).
In one study, 85 psoriasis patients began taking 0.5 micrograms (g) of oral calcitriol (the active form of vitamin D3) per day. Researchers increased the daily dosage by 0.5 g every two weeks, as long as lab tests were normal. Volunteers received treatment for between 6-36 months.
Patients saw significant reductions in Psoriasis Area and Severity Index (PASI) scores at six months and even greater improvements at 24 months. Nearly 27% had complete improvement in symptoms, while 88% had some improvement (31,40).
The results are promising, and no negative side effects were reported.
But high quality clinical trials are needed to make firm conclusions.
Antioxidants are molecules that protect cells againstoxidative stress.
A handful of studies have linked oxidative stress and psoriasis, and certain antioxidants have been proposed as a supplemental therapy for the disease (41,42).
Seleniumis an antioxidant mineral found in vegetables, meat, fish, poultry, grains, and eggs.
Evidence is conflicting as to whether selenium deficiency directly contributes to psoriasis risk (43,44).
Small studies, however, have found that it may play an indirect role. Selenium helps inhibit activity of a protein calledosteopontin, and high osteopontin levels are thought to increase psoriasis risk (45,46).
Its unclear whether selenium supplements are helpful in reducing symptoms though.
Continue reading here:
Psoriasis Treatment: Does Your Diet Matter? - The Good Men Project (blog)
