If you have psoriasis, you’ve probably wondered whether something you’re eating is making it worse. A lot of people with psoriasis report that certain foods seem to trigger flares. Worth saying upfront: the research on diet and psoriasis is still fairly thin. Most of what we know comes from surveys of what people report noticing, not large, tightly controlled studies. That doesn’t mean it’s not worth paying attention to; it just means the honest answer here is “this varies a lot person to person,” not “cut these foods and you’ll be cured.”
Sugar
In a 2017 survey of more than 1,200 people with psoriasis, sugar was the most commonly self-reported trigger. There’s some evidence that excess sugar intake can promote inflammation in the body generally, which lines up with what people are reporting, even if it isn’t proof of a direct cause-and-effect link for every person.
Alcohol
Alcohol has one of the better-supported links on this list. It can disrupt normal immune system function, and some research suggests it may not just worsen existing psoriasis, but also increase the risk of developing it in the first place. If you’re looking for one change with the most evidence behind it, cutting back on alcohol is probably it.
Tomatoes, Potatoes, Peppers, and Eggplant (the “Nightshade” Vegetables)
Tomatoes, potatoes, eggplant, and bell peppers, a group sometimes called “nightshade” vegetables, get talked about constantly in psoriasis diet discussions. In a 2017 survey, 52% of people who cut these out reported improved symptoms. That’s a striking number, but it’s self-reported, not tested against a placebo, so it’s worth treating as a lead worth trying rather than settled science. These vegetables are also nutritious foods for people without a sensitivity to them, so cutting them out isn’t automatically the right call for everyone.
Gluten
This one has a real split. People with psoriasis have higher rates of celiac disease than the general population, and if you have celiac disease or a confirmed gluten sensitivity, gluten absolutely can worsen psoriasis, the same way it damages your gut. In that case, a dermatologist or doctor will typically recommend cutting gluten completely.
For people without a confirmed sensitivity, the evidence is much weaker. A couple of small studies have shown improvement in people who cut out gluten, but we’re talking about a handful of participants, not the kind of large trial that would let anyone confidently recommend it broadly.
Dairy, Red Meat, and Saturated Fat
There’s moderate evidence that a diet higher in saturated fat, including red meat and full-fat dairy, is associated with more severe psoriasis symptoms. This tracks with what’s known about inflammation generally, saturated fat is linked to inflammation regardless of psoriasis, so this isn’t a wildly surprising finding, just a moderately supported one.
What This Doesn’t Mean
None of this means any of these foods cause psoriasis. Psoriasis is an autoimmune condition that exists whether or not you ever touch sugar or nightshade vegetables. What diet may do, for some people, is make an existing flare somewhat better or worse. And triggers genuinely vary from person to person; something that flares one person’s psoriasis might do nothing for someone else’s.
How to Actually Figure Out Your Own Triggers
The most useful approach isn’t cutting out everything on this list at once. It’s tracking. Keep a simple food and symptom diary for a few weeks, noting what you eat and how your skin looks and feels. Patterns tend to show up over time that a single elimination never would.
If you want to test something specific, like gluten, the National Psoriasis Foundation suggests eliminating it for a minimum of three months, since that’s roughly how long it takes inflammation to settle enough to judge whether it made a real difference, then reintroducing it and tracking what happens.
One important caution: talk to a doctor or registered dietitian before eliminating entire food groups, especially gluten or dairy long-term. Whole grains and dairy provide nutrients that are genuinely hard to replace if you cut them out without a plan, and unsupervised elimination diets can create new problems while you’re trying to solve this one.
When to See a Dermatologist or Dietitian
- You’re considering eliminating an entire food group and want guidance on doing it safely
- You suspect celiac disease or a gluten sensitivity and haven’t been tested
- Diet changes alone aren’t making a meaningful difference, and you want to talk through other treatment options
Diet can be one piece of managing psoriasis, but it’s rarely the whole picture, and it works best alongside whatever treatment plan you and your dermatologist have already built.
Mike Marenick is the founder of HealFast Skincare and holds the patent for his invention, Ovasome Technology, used in skincare formulations. He began developing skincare products after watching his mother manage psoriasis for decades, and has spent over twenty years formulating treatments for chronic skin conditions. His work has been featured on Home Shopping Network, in two national infomercials, and in more than 300 publications including Vogue, Newsweek, and Allure. He is not a medical doctor — always consult a dermatologist for diagnosis and treatment of skin conditions.