Psoriasis can start at any time during your life. It is a T-cell mediated inflammatory dermatological disorder that is still not well understood. This abnormal skin condition causes skin cells to be produced faster, and the cells mature and reach the outside layers of the skin at a faster rate. A person with psoriasis will notice some red spots on their skin and flaky dry skin over any part of their body. According to research the prevalence of psoriasis in the population is between 0,6 % and 4,8 %.
The following are typical signs of what a person may experience:
- Dryness of skin
- Red, scaly patches which can develop on any part of the body such as
- Elbows
- Knees
- Nails
- Lower back
Studies have also linked psoriasis to the following lifestyle factors:
- Smoking
- Alcohol consumption
- Diet
- Emotional stress
- Infections
- Nutrient deficiency
- Protein
- Folate
Omega-3 from fish oils, plant leaves and some vegetable oils may improve symptoms.
CAUSES OF PSORIASIS?
Although the exact cause of psoriasis is unknown, some studies have shown that leukotrienes, which causes inflammation, have been found in high levels in the skin of people with psoriasis. Arachidonic acid, which is found in animal fats, is metabolised to leukotrienes.
It is also considered that some people are genetically prone to have the disease.
Other causes, such as autoimmune disorders, stress, environmental factors, hormones, medicines, infections and sunlight, are not scientifically proven.
It is interesting to note that 10 % of psoriatic patients also develop arthritis.
TYPES OF PSORIASIS
Plaque (discoid) psoriasis:
It is the most common type affecting 9 out of 10 psoriasis sufferers. The skin develops clearly defined patches of pink or red skin called plaques, which are covered with dry, crusty, silvery scales, which flake off.
Guttate psoriasis:
Usually in children and adolescents. It can be the first sign of a susceptibility to the condition. In a flare-up numerous small round red spots appear on the body, limbs and scalp.
Flexural psoriasis:
It do not scale, but the patches are inflamed and red and usually occur in the folds of the body. It tends to occur more often in older people, particularly older women.
Nail psoriasis:
More common in people over 40 years and is strongly linked with the development of psoriatic arthritis. Nails become ridged and they may lift away from the finger.
Localised pustular psoriasis:
It is more common in adults than in children. Pus-filled spots form on the palms and soles. The affected areas are painful and might resist therapy.
Erythrodermic psoriasis:
It could be life threatening, but it is a rare condition. Large areas of the skin become inflamed and scaly, and patients could lose their ability to control their body temperature and suffer from nutrient and fluid loss.
Psoriatic arthritis:
It is estimated that 6 % of people with psoriasis suffer from psoriatic arthritis (stiff, painful and inflamed joints). With psoriatic arthritis an entire finger or toe becomes swollen and inflamed, rather than an individual joint. Common sites are the hands, feet, spine and neck.
TREATMENT
Psoriasis can’t be cured, therefore treatment options are mainly to improve the symptoms. These options include medicines applied locally on the skin; however, oral and intravenous options are also available.
DIETARY CONCERNS ASSOCIATED WITH THE USE OF MEDICINES COMMONLY PRESCRIBED IN PSORIASIS
The nutritional status of an individual with regards to the absorption, metabolism and excretion of nutrients in the food can be affected by medicines, such as methotrexate, used in the treatment of psoriasis.
Methotrexate is often prescribed as a cytotoxic therapy for suppressing psoriasis. It may cause deficiencies of vitamin B12 and folic acid and such lower serum levels may lead to megaloblastic anaemia. Methotrexate may also cause nausea, abdominal pain and mouth ulcers, which, when severe, may require dietary treatment.
Dietary suggestions
♦ Avoid alcohol consumption.
♦ Eat a diet that includes good sources of folic acid (fresh green leafy vegetables, fruit, organ meats, dried nutritional yeast) and vitamin B12 (yeast, liver, beef, eggs, kidney).
NUTRITIONAL TREATMENT OF PSORIASIS
Food allergies have not been as strongly linked to psoriasis as they have been to other skin diseases, such as eczema. Currently there is no consensus on any specific dietary treatment protocol for psoriasis. Limited evidence exists for a gluten-free diet or a low protein diet, fasting and supplementation with evening primrose oil, taurine and zinc sulphate.
A patient with psoriasis should follow a well-balanced and healthy diet to prevent nutritional deficiencies. Individuals who suspect food allergies or intolerances should confirm this with a proper diagnosis (RAST and ELISA are two tests that can be used by a doctor to confirm a food allergy). It is unwise to follow an elimination or exclusion diet without proper diagnosis of a food allergy, since such a diet can affect the overall well-being and nutritional status of a patient.
Omega-3 fatty acids:
Omega-3 is a group of unsaturated fatty acids found primarily in marine oils and algae, and to a lesser extent in plant leaves and some vegetable oils such as canola. Two such important omega-3 fatty acids are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are abundant in fish such as salmon, mackerel, herring, tuna, snoek, trout, sardines and pilchards.
EPA, DHA together with alpha-linolenic acid have been shown to reduce inflammation by reducing the synthesis of leukotrienes thought to play a role in psoriasis.
Various studies have been done and although there are limitations to the studies, 1 out of 4 of these studies showed a beneficial effect after oral supplementation with omega-3 fatty acids. Dietary supplementation with fish oil rich in EPA [fish oil (10 g) and EPA (3 g)] taken for 8 weeks, for instance, showed a mild to modest improvement in psoriatic symptoms, such as the itching, erythema and scaling in psoriasis. The improvement occurred in patients with chronic stable psoriasis and was achieved without any other changes in their diet. Treatment with EPA, therefore, may be important as an adjuvant therapy to more conventional medicines, such as methotrexate, especially for woman of childbearing age.
Supplementation with other oils such as evening primrose oil is not recommended because clinical studies failed to proof a benefit.
NUTRITIONAL RECOMMENDATIONS
- Eat a variety of foods.
- Choose a diet with adequate grain products, vegetables and fruits. Include at least 5 portions of fresh fruit and vegetables per day, especially those rich in beta-carotene, e.g. carrots, apricots, sweet potatoes and those rich in vitamin C, e.g. broccoli, oranges, cabbage, potatoes, guavas, tomatoes and sweet peppers.
- Choose a diet low in total fat (less than 30 % of total energy intake) and saturated fat. Limit the intake of animal fat by eating lean meat and low-fat dairy products.
- Gluten-free diets could be beneficial for patients with a confirmed allergy or sensitivity to gluten.
- Alcohol is known to cause flare-ups of psoriasis. It stimulates the release of histamine which aggravates skin lesions. Patients should avoid alcohol or use it in moderation or per occasion.
- Eat oily fish regularly to increase the intake of omega-3 fatty acids in the diet. Substitute red meat with salmon, mackerel, snoek, trout, sardines, pilchards and shellfish at least three times per week (see Table below).
SOURCES OF OMEGA-3 FATTY ACIDS
| Food source: (150 g raw mass) | Total fat (g) | Total omega-3 (g) (including DHA and EPA) |
| Sardines in sardine oil | 23,25 | 4,95 |
| High fat, grilled, e.g. herring, butterfish | 17,40 | 3,33 |
| Salmon | 19,50 | 2,79 |
| Mackerel | 20,85 | 2,50 |
| Pilchards in brine | 8,10 | 2,42 |
| Herring | 13,50 | 2,40 |
| Anchovy | 7,20 | 2,10 |
| Smoorsnoek (medium fat fish, potato and onion) | 7,05 | 1,04 |
| Tuna in brine | 3,75 | 0,75 |
| Trout | 4,05 | 0,60 |
| Catfish | 6,45 | 0,45 |
| Haddock | 1,05 | 0,30 |
| Lobster | 1,35 | 0,30 |
| Shrimp | 1,65 | 0,45 |
SUPPLEMENTS
- Omega-3 fatty acid supplements can increase the dietary intake of these nutrients.
- If a supplement is taken, do not exceed the supplier’s recommended daily dose (see product’s information leaflet) and take the supplement in consultation with your doctor.
- Beware of omega-3 fatty acid supplements that also contain large dosages (more than 150 % of the RDA) of vitamins A, D and E, especially if the omega-3 fatty acid supplement is taken in combination with other vitamin and mineral supplements that also contain these vitamins.
- Any decision to take supplements in large doses should be based on the advice of the doctor or dietitian.
Reference:
- http://www.sun.ac.za/english/faculty/healthsciences/nicus/Documents/Files/Files/Fact_sheets/Psoriasis%20and%20Nutrition.pdf Accessed 23 April 2023.
NICUS
Nutrition Information Centre University of Stellenbosch
Division of Human Nutrition
E-Mail: nicus@sun.ac.za
WEBSITE: http://www.sun.ac.za/nicus/
