Foods to eat and avoid with psoriasis: the list the evidence will actually sign

Start from what has been tested, not from what has been blamed

Search for foods to eat with psoriasis and you get two kinds of page. The first is a list of superfoods with a photograph of salmon. The second is a list of forbidden foods, usually longer, usually starting with nightshades. Neither kind tends to say where the list came from, and that matters, because the research on diet and psoriasis is thin enough that a list which does not name its source is almost certainly a list of things people have blamed rather than things anyone has tested.

When the Medical Board of the National Psoriasis Foundation went through the literature to write dietary recommendations, it found 55 studies covering 4534 people with psoriasis, and came out with exactly two strong or conditional recommendations about food: weight reduction with a reduced-calorie diet for people who are overweight, and a gluten-free diet only for people who test positive for markers of gluten sensitivity. Everything else it filed under low-quality data that may affect psoriasis ^[2]. That was 2018. A 2025 systematic review reached the same place, describing the pattern-level evidence as promising and the high-quality evidence as lacking ^[7], and a scoping review of the whole field concluded that there are no specific, evidence-based dietary guidelines for psoriasis at all ^[12].

So the list below is built backwards from that. It puts on the eat side the pattern that was tested in a trial, as its protocol describes that pattern, and what the people whose job is to weigh the trials recommend; it puts on the avoid side only what has data behind it. The result is shorter than you have been told, and that is the point.

Sources for this section: [2] Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review · [7] Evidence-based dietary recommendations for patients with psoriasis: A systematic review · [12] The role of diet in the management of psoriasis: a scoping review

Eat: the Mediterranean pattern, because it is the one with a trial

For years the Mediterranean diet's case in psoriasis rested on observational studies, which can show that people who eat that way have milder disease without showing that eating that way causes it. In 2025 that changed. A randomised clinical trial put 38 people with mild to moderate psoriasis on either a 16-week dietitian-guided Mediterranean diet or standard low-fat dietary advice without a dietitian, and measured plaques with the standard severity index. The diet group improved by a between-group difference of -3.4 on that index, and nine of the 19 people in the diet arm reached a 75% reduction in severity, against none in the control arm ^[1].

It is one trial, it is small, it was open-label, and it was run at a single clinic in Madrid, with dietitian counselling and olive oil supplied, against low-fat advice with no dietitian ^[1]. Those are real limits and you should hold them in mind. But it is a randomised trial with a clinical endpoint, which none of the other named diets discussed on this page has, and it fits with the clinical-practice review that describes the Mediterranean diet as a good option for people with psoriasis because of its anti-inflammatory effects and its heart benefits ^[6].

The trial's published protocol says what the pattern was: extra virgin olive oil as the cooking and dressing fat, two or more servings of vegetables a day, three or more of fruit, legumes three or more times a week, fish or seafood three or more times a week including oily fish, nuts three or more times a week, white meat chosen over red or processed meat, whole grains over refined, and cream, butter, sugary drinks, pastries and ultra-processed foods limited or eliminated ^[13]. It does not mean any single ingredient is medicine. The people in the trial improved on the whole pattern, delivered with counselling and menus, and a pattern is not a supplement.

Notice, too, one item in that protocol: sofrito, a sauce of chopped tomato, garlic and onion simmered in olive oil, which participants were encouraged to cook with at least twice a week ^[13]. That fact is going to matter further down.

Sources for this section: [1] Mediterranean Diet and Patients With Psoriasis: The MEDIPSO Randomized Clinical Trial · [6] Nutrition and Psoriasis: The Latest Evidence and How to Approach Nutrition in Clinical Practice

Eat less, if there is weight to lose: the strongest dietary evidence there is

This is the recommendation most people skip past because it does not name a food, and it is the one with the best evidence. Obesity and psoriasis travel together, the clinical-practice literature describes a strong association between obesity and psoriatic disease activity and progression ^[6], and the National Psoriasis Foundation's only strong dietary recommendation is weight reduction for people who are overweight or obese ^[2].

The evidence is not just association. A randomised trial in Italy took 303 overweight or obese patients with moderate-to-severe plaque psoriasis whose skin had not cleared on systemic treatment, and gave half of them a 20-week diet and exercise programme. The median reduction in severity was 48% in the diet arm against 25.5% in the group who were only given information about the value of losing weight ^[3]. A 2026 meta-analysis pooling thirteen randomised trials found weight-loss interventions produced a greater reduction in severity than control, and rated the evidence high-certainty, recommending that weight loss be considered part of routine treatment ^[5].

If that applies to you, it belongs at the top of your food list, above any question about tomatoes. The Mediterranean pattern and a modest calorie reduction are compatible, and the trial that showed plaques improving on the Mediterranean diet also showed blood sugar control improving in the same people ^[1].

Sources for this section: [1] Mediterranean Diet and Patients With Psoriasis: The MEDIPSO Randomized Clinical Trial · [2] Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review · [3] Diet and physical exercise in psoriasis: a randomized controlled trial · [5] Impact of weight-loss interventions on psoriasis severity: systematic review and meta-analysis · [6] Nutrition and Psoriasis: The Latest Evidence and How to Approach Nutrition in Clinical Practice

Avoid: heavy drinking and sugary drinks, the two with data

Now the other side of the list, which is where the internet gets expansive and the evidence gets narrow. Two things have data behind them that go beyond someone's recollection.

The first is alcohol. Both recent systematic reviews of psoriasis diet advise avoiding it ^[7], and there is a separate essay on this site about how much the evidence actually supports and where it stops. The second is sugar, specifically sugar in drinks. In a prospective cohort of people receiving psoriasis treatment, drinking sugary drinks four or more times a week was associated with a much lower chance of reaching a meaningful improvement at eight weeks ^[11]. In the UK Biobank, people whose diets were highest in free sugars had a higher rate of developing psoriasis over thirteen years of follow-up, while people highest in fibre and starch had a lower rate ^[10].

Those are associations, not trials, and they cannot tell you that giving up soft drink will clear your skin. What they can tell you is where the data points: sugary drinks are the item people with psoriasis were drinking more of and the item the trial diet limited ^[13], while tomatoes are the item the trial diet cooked with. Of the two, the drink is the one with a case against it.

Sources for this section: [7] Evidence-based dietary recommendations for patients with psoriasis: A systematic review · [10] Association between carbohydrate intake and the risk of psoriasis: a prospective cohort study based on UK Biobank · [11] Sugary Drinks and High-Fat Foods are Associated with Poor Treatment Response in Psoriasis: A Prospective Study in Shanghai

Avoid conditionally: gluten, but only after a test

Gluten is on every avoid list and it earns its place on this one, with a condition attached that the other lists leave off. The National Psoriasis Foundation recommends a gluten-free diet only for people who test positive for markers of gluten sensitivity ^[2], and the clinical-practice review says the same: for people with a coeliac diagnosis or positive antibodies, gluten-free eating could reduce psoriasis severity ^[6].

The recommendation is conditional on a test, which puts the test first. If it is negative, none of the guidance cited here supports gluten avoidance for psoriasis, and you have bread back. If it is positive, you have a diagnosis and a reason, which is what a food rule should have. The gluten essay on this site walks through the test and the decision.

Sources for this section: [2] Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review · [6] Nutrition and Psoriasis: The Latest Evidence and How to Approach Nutrition in Clinical Practice

Not on the avoid list: dairy, nightshades and everything else people blame

Here is where this list parts company with most of the others. Dairy, tomatoes, capsicum, eggplant and potatoes are not on it, and the reason is that nothing cited on this page supports avoiding them for everyone: the guideline recommendations do not include them, and the one diet trial kept them in.

The reason they appear everywhere else is a single survey. When the National Psoriasis Foundation asked its members what they had tried, 1206 people answered, and the foods most often reported as helping when removed were alcohol, gluten and nightshades, each named by roughly half of the people who had tried cutting them ^[4]. That is a real finding about what people believe, and it is worth respecting as such. It is not a finding about what the foods do. The same people were describing changes they made and what their skin did afterwards, and there was no control group to say how many would have improved anyway.

Set that survey beside the trials and the picture is clear. The Mediterranean pattern that improved plaques in a randomised trial was taught with a tomato sauce in the cooking and fermented dairy in the pattern ^[13]. The professional guidance that reviewed the literature makes its recommendations about weight and about gluten, and none about removing dairy or nightshades ^[2]. The 2025 review that lists foods with reports of aggravating psoriasis, dairy among them, says in the same paragraph that high-quality evidence is lacking ^[7]. A universal nightshade ban is hard to reconcile with the one dietary-pattern trial that improved psoriasis, and none of the guidance cited here asks for one.

That does not mean you personally cannot react to a food. It means a blanket ban is not how anyone finds out. A suspected food is a question for the dermatologist or dietitian who knows your case, and it is answered one food at a time, with the food put back on purpose, not by removing four things at once; the elimination-diets essay explains why the four-at-once version cannot answer the question.

Sources for this section: [1] Mediterranean Diet and Patients With Psoriasis: The MEDIPSO Randomized Clinical Trial · [2] Dietary Recommendations for Adults With Psoriasis or Psoriatic Arthritis From the Medical Board of the National Psoriasis Foundation: A Systematic Review · [4] Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey · [7] Evidence-based dietary recommendations for patients with psoriasis: A systematic review

The cost of the long list, which nobody puts on the page

There is a reason to be careful about avoid-lists beyond their being unsupported. People with psoriasis are already measured as eating differently from people without it, and not in the direction the avoid-lists assume. In the same national survey, compared with matched controls, respondents ate significantly less sugar, which is fine, but also significantly less whole-grain fibre, dairy and calcium ^[4]. In the UK Biobank, people with the most severe psoriasis were less likely to meet the fruit and vegetable guideline than people not on treatment, and people with psoriasis overall ate more red and processed meat, sodium, free sugars and alcohol than people without it ^[9]. A UK survey using a food-frequency questionnaire found people with psoriasis eating too much free sugar and too little fibre relative to reference values ^[8].

Look at what that adds up to. The things the avoid-lists remove, dairy and a whole category of vegetables, are things people with psoriasis are already short of. The things the evidence points at, free sugars, processed meat and alcohol, are things they are eating more of. A long avoid-list gets the direction of the problem backwards, and it does so for a person who is already paying in money and social life for a diet that was never shown to work.

Sources for this section: [4] Dietary Behaviors in Psoriasis: Patient-Reported Outcomes from a U.S. National Survey · [8] Macronutrient intakes and associations with psoriasis severity: a cross-sectional analysis of the asking people with psoriasis about lifestyle and eating (APPLE) study · [9] Are psoriasis severity and comorbidities associated with diet quality? A cross-sectional analysis using UK Biobank

The list, and the trolley that follows from it

Eat, as a pattern: vegetables including tomatoes, capsicum and eggplant; fruit; legumes; whole grains; fish; olive oil; nuts and seeds; with fermented dairy such as yoghurt and cheese part of the pattern as the trial described it. If you are overweight, weight reduction is the change with the strongest evidence. The reviews advise avoiding alcohol; the trial diet limited sugary drinks, pastries and ultra-processed food. Gluten-free eating is for people whose test says so.

In shopping order that is a trolley with most of its weight in the fruit and vegetable section, a tin shelf of beans, lentils and chickpeas, a bag of oats and some wholegrain bread or pasta, tinned or fresh fish, a bottle of olive oil, a bag of nuts, and the dairy you already buy. Nothing on it is exotic and nothing on it costs more than what it replaces.

The free seven-day psoriasis week on this site is that trolley turned into meals: twenty-one recipes built on the Mediterranean pattern, with a shopping list and per-serving nutrition, and tomatoes in several of them on purpose. If a week of that suits you, the cookbook is the same pattern with a hundred recipes, a 28-day plan and the shopping worked out.