According to the American Academy of Dermatology (AAD), psoriasis affects about 7.5 million Americans, most of whom are adults. About 80 percent of them experience this medical condition in a mild or moderate form. However, the remaining 20 percent are affected by a moderate to severe form that affects more than 5 percent of the body’s surface.
Up to 40 percent of those with this medical condition have psoriatic arthritis, characterized by painful joint inflammation that produces arthritic symptoms.
According to the Mayo Clinic, this skin condition occurs when the life cycle of skin cells changes. Unfortunately, it isn’t curable, meaning that it is chronic and can recur.
The AAD says that psoriasis generally shows on the scalp, knees, elbows, hands and feet.
Though there are many forms of psoriasis, one is most common -- plaque psoriasis. In fact, this form affects 80 to 90 percent of psoriasis sufferers. Plaque psoriasis causes several symptoms, most notably raised, red patches of skin covered with silvery scales.
One thing to know about psoriasis is that it can elevate the chance of developing other health issues. For example, those with psoriasis have a seven and a half times greater chance of developing ulcerative colitis and are 3.8 times more likely to develop Crohn’s disease.
Those with psoriasis also have an increased risk of lymphoma, heart disease, obesity, Type 2 diabetes and metabolic syndrome.
It has been said that mental health conditions like depression are more common in those with psoriasis. In fact, experts say that up to half of those with psoriasis may be depressed.
So why does psoriasis occur?
No one knows the exact reason that psoriasis occurs. However, experts say that it most likely revolves around miscommunication related to the immune systemThe Mayo Clinic says that psoriasis triggers include: cold weather, infections, skin injury, stress, too much alcohol, smoking and some medications (like lithium and beta blockers used for high blood pressure).
Some say that diet can play a part in psoriasis symptoms. As a result, some experts say to avoid the following seven foods.
1. Wheat
We’ve all seen or heard something about gluten. But most of us don’t know what it is. Gluten is a protein found in common foods, like wheat products. And it may play a part in the development of psoriasis.
According to Everyday Health, the relationship between psoriasis and gluten isn’t clear. However, some link celiac disease to an elevated risk of psoriasis.
That said, experts warn that this is just a theory. “While some skin conditions are worsened by wheat, no scientific studies support a gluten-free diet for psoriasis,” Dr. Paul Yamauchi tells Everyday Health.
2. Alcohol
There may be a link between alcohol consumption and psoriasis. According to Healthline, a study conducted in 2010 concluded that those with this health condition drink more. And another study found that the incidence of psoriasis was elevated in subjects who drank non-"light" beer two or three times a week.
The National Psoriasis Foundation has offered some guidance on this concept. They suggest limiting alcohol. And in the case of severe psoriasis, it may be prudent to cut out alcohol altogether.
3. Tomatoes
We’ve all heard that nutrient-rich tomatoes are good for us. But for those with psoriasis, the opposite may be true.
According to ABC News, tomatoes are considered “nightshade vegetables.” And it is thought that nightshade vegetables may affect certain people with this condition. That said, ABC News warns that there is no scientific research to back up this belief. The only way to tell is to experiment with eliminating nightshade vegetables from the diet.
4. Processed Foods
Processed foods are often loaded with fat and sugar, which can pack on the pounds. While extra weight is frustrating when jeans become tight, it also may worsen psoriasis.
According to the National Psoriasis Foundation, a relatively recent study found that obesity elevated the risk of psoriatic disease. In fact, researchers linked higher body mass index (BMI) with the risk of developing both psoriasis and psoriatic arthritis. Weight also played a factor in disease severity. Study author Dr. Wilson Liao said obesity may “provide the nudge that triggers psoriasis.”
That said, weight loss can help. Another study found that losing weight can decrease the severity of the condition. In this study, “dietary intervention” was stressed.
"There was a clear correlation between the amount of weight loss and the improvement of psoriasis," said Dr. Luigi Naldi, the study's lead author, as reported by the NPF. "Patients who lost more weight experienced a larger improvement in psoriasis.” However, smaller amounts of weight shed were also found to help.
5. Refined Sugars
Diabetes is an inflammatory disease that affects more than 29 million Americans. And if you have psoriasis, your chance of developing the disease is higher.
According to WebMD, one study found that the risk of developing diabetes is twice as high in those with the most severe form of the condition. And other studies have linked a doubled risk of heart attack, stroke and even death to psoriasis.
“Our results underline the importance of considering patients with psoriasis as a high-risk population in terms of diabetes and [heart disease and stroke] risk. Screening for diabetes and cardiovascular disease risk factors in these patients is warranted," says researcher Ole Ahlehoff, M.D., Ph.D., as reported by WebMD.
6. Dairy
According to Everyday Health, though there isn’t much evidence to prove it, diet could be linked to severity of psoriasis. This includes dairy foods. Dr. Jerry Bagel tells Everyday Health that it’s OK to remove foods if they exacerbate psoriasis.
Dairy products are inflammatory foods. This is because they contain something called arachidonic acid. “Cow’s milk is one of the biggest culprits,” Bagel tells Everyday Health. This is thought to be due to a protein called casein, which has been shown to cause inflammation.
7. Fatty Red Meats
In general, experts say to avoid foods that cause inflammation. One of these foods is fatty red meats. Instead, the National Psoriasis Foundation suggests adopting anti-inflammatory foods into your diet.
For example, replacing fatty red meat with cold-water fish like albacore tuna, salmon or herring can be beneficial. Fish are anti-inflammatory foods that contain omega-3s. Other options are walnuts, fruits, vegetables and pumpkin seeds.