The Role of Diet in Psoriasis Management

Introduction

Psoriasis is a life-long skin condition that causes inflammation. It is classified as a chronic disease and can affect one’s quality of life.¹  As a result of psoriasis, it results in the formation of scaly plaques that are scaly pink or salmon-coloured and look black, brown or white on the skin. These patches are common in areas such as the elbows, knees, scalp or lower-back.² The visibility of plaques, their relapsing nature and autoimmune response forms the most worrisome aspect of condition. Although, it is not a life-threatening medical condition, psoriasis still influences a person’s relationships, work, and family lifestyle. 

Who does psoriasis affect?

 Psoriasis can affect both people assigned male at birth, and people assigned female at birth. The peak age differs depending on sex. People AWAB have an earlier onset of the disease - between 20 years to 50 years. Whereas, people AMAB usually have the disease onset later, at 60 to 69 years. Statistics show that 1.5% to 11.43% of people around the world are affected by the disease.² Hence, it is very important that we understand how to manage and treat it.

What contributes to psoriasis?

Research has shown thatpsoriatic plaques are due to adaptive immunity which helps act as a protective barrier between our bodies and microbial contactThe skin’s topmost layer called the epidermis forms an environmental barrier. When the epidermis proliferates, it is called hyperplasia. Hyperlasia leads to the enlargement of the skin tissue. . This  happens because of two types of immune cells:, natural killer cells and natural killer T cells. The proliferation of keratinocytes occurs due to the activation of these cells leading to skin inflammation in psoriasis.^2,3

Understanding the link between diet and psoriasis

The role of inflammation in psoriasis

Psoriasis is an autoimmune condition that results in both inflammation.The T-cells, specific cells that play a part in immune response, cause the activation of molecules that trigger an inflammatory response.³ This causes an increase in skin turnover and the formation of skin lesions. Therefore, there is an increase in keratinocytes (cells that make up the epidermis layer of the skin).  This hyperproliferation of keratinocytes leads to the formation of skin lesions.³ 

Inflammation can be managed through various remedies - especially through diet. By avoiding specific pro-inflammatory foods, individuals can manage their psoriasis better. This influences the occurrence of psoriatic skin lesions and severity of of preexisting lesions.

Things that may trigger psoriasis flare-ups

There are various things that should be avoided if you have psoriasis - mainly involving lifestyle and food choices. Foods that should be avoided include:⁴

• Excessive consumption of simple sugars 
• Alcohol consumption - especially for people AFAB, the greater their alcohol intake, the greater their severity of psoriasis
• Red meat - contains short fatty acids that increase inflammation of the skin.

Foods that may help reduce inflammation and improve symptoms

Similarly, just as there are a range of pro-inflammatory foods to avoid if you have psoriasis, there are also food products that contain anti-inflammatory properties. These food include:⁴

• Omega-3 rich foods such as fish like salmon and mackerel
• Leafy green vegetables such as spinach and kale
• Olive oil 
• Sources of vitamin D
• Soybean
• Probiotics

Fish is highly recommended for those who have psoriasis as they have several beneficial components. They are a source of vitamin B12, vitamin D, vitamin A and selenium. This means that fish contain many anti-oxidative properties that reduce inflammation.⁴ 

Soybean is also preferred as it is considered to be an anti-psoriasis product. It contains a compound called genestein which has been shown to prevent the expression of molecules that promote inflammation.⁴

Supplements can also be taken to reduce inflammation, especially through the use of Vitamin D. It is helpful in the treatment and control of psoriatic lesions as it strengthens immunity and regulates proliferation and maturation of keratinocytes. Keratinocytes are cells that found in the skin and make up the majority of the epidermis. Typical sources of vitamin D are sunlight, topical vitamin D analogues and Vitamin D supplements.⁵ 

Probiotics are live microorganisms found within food that help promote a healthy microbiome in the body. The maintainence of the gut microbiota plays a vital role in general health. By consuming probiotics, the microbiome is altered to show a greater abuncance of beneficial bacteria such as Bacteroides fragilis which has been proven to restore the skin barrier. Hence, it is useful for patients with psoriasis to ease the visibility of their plaques.⁴

A study based on dietary modification for people with psoriasis showed positive outcomes in 44.6% people consuming omega-3 or fish oil, 42.5% with vegetarian diet, 38.4% organic foods, 34.6% fruits and 41% with supplements such as oral vitamin D and 40.6% probiotics.⁶

The mediterranean diet and its benefits for psoriasis

Explanation of the mediterranean diet and its components

The Mediterranean diet is a diet followed by the rural Mediterranean community. Their diet pattern has been found to reduce mortality, the occurence of cancer, and heart problems. The base of their meal is consuming whole grains, fruits, and vegetables. Nuts, olive oil and seeds are theirsources of dietary fats. Dairy is limited to low-fat fermented items and cheese. Non-vegetarian meals containing seafood, white meat, eggs, and legumes are taken twice a week. Whereas red meats and processed food are limited to once a week. Pastries and confectionery are preserved for only special events.

The Mediterranean diet is nutritional as they provide food  sources with an abundance of polyphenolic compounds, vitamin A and C as well as micronutrients. Their diet has a lot of food with antioxidant and anti-inflammatory properties. They also are rich in fibre which helps maintains healthy gut health and microbiome. This is important as the microbiome helps in metabolism and the regulation of inflammatory response, which is key in controlling psoriasis.⁷

Gluten free diet and its potential impact on psoriasis

Gluten is a complex protein that is commonly found in wheat, rye, and barley. Studies have shown an assosciation between coeliac disease and psoriasis. A study where participants were put on a gluten-free diet, along with an injection of antibodies to gliadin. Gliadin is a protein found within gluten, leading to an immune response for those with coeliac disease. It was found that all 30 patients had a lower severity of psoriasis. However, this improvement was only shown if patients had cut out gluten completely. Hence, this is only suggested for those with the antiody against gliadin.⁴   

Fasting for psoriasis patients

Fasting has been proven to show benefits for those who have psoriasis. In a study with 121 psoriasis patients, patients were made to intermittent fast during the month of Ramadan. It was found that the mean PASI score was signifcantly reduced at the end of the study, suggesting that the severity of patients’ psoriasis had decreased. This is likely due to the presence of fewer T-cells and fewer cytokines released - therefore, decreased inflammation.⁸ 

Vegetarian diets for psoriasis patients

A vegetarian diet consists of no consummation of meat. Hence, it has been proven to be beneficial for those with psoriasis. There is an increase in consumption of antioxidants and a decrease in trans fats. Therefore, it is likely to help with the inflammation associated with the disease.⁹

Personalizing diet and lifestyle strategies

The individualized nature of psoriasis management

Every patient with psoriasis learns what triggers or causes flare-ups of the skin condition. For some, it may be:

• Stress, 
• Sleep disturbances, 
• Cold and dry climates, 
• Spicy food, 
• Gluten rich foods
• Dairy products 

Before deciding on whether to remove a food item completely from your diet, it is recommended to consult a healthcare professional first. It is also recommended to keep a food diary to help recognise the food items that affect your condition as every individual may react differently. 

Summary

Psoriasis is a chronic inflammatory, non-contagious, auto-immune skin condition that is triggered by a range of factors. These factors include stress, certain food products or environmental factors. It does not have a cure and requires a holistic approach. Risk factors contributing to the disease occurrence is genetic, with people AFAB and bimodal age group between 30-39 and 60-60 years more likely to have it. Studies have been conducted that show the effect of diet in reducing the time interval between flare-ups or  the severity of the plagues. The disease is due to  an inflammatory response in the body caused by activation of T-cells, that regulate the process. Inflammation causes an increase in turnover of skin cells faster than their actual period resulting in the formation of scaly, itchy plagues. Therefore, a diet with many antioxidant and anti-inflammatory properties helps in controlling the severity of the scaly lesions. Other foods with pro-inflammatory mechanisms should be avoided to help reduce the severity of psoriasis. There is still a lot of further research yet to be done about the importance of diets in treating psoriasis. However, maintaining a healthy diet is a good way to manage it.