There is a dearth of research into how the nutrients and foods we eat affect common skin conditions. The best advice, it seems, is to eat fresh unprocessed meals, and ensure there are no nutritional gaps that can lead to insufficiencies of essential nutrients.
If you keep a food and fluid diary for a number of weeks, doing an audit of that can help identify potential problems with nutrients that are pretty scarce in many Irish diets. Vitamin D is one such hormone-like substance that is important for immune function and healthy skin. A diary can also highlight imbalances in essential fats. For example, too much omega 6 and not enough omega 3 polyunsaturated fatty acids can be pro-inflammatory.
A balanced intake of healthy fats, plant and lean animal proteins, and unrefined carbohydrates is important, but your lifestyle is also worth scrutinising. Excess alcohol and cigarette smoking aggravate many skin conditions. Being overweight can make certain conditions such as psoriasis worse, and many skin disorders flare up at particularly stressful times.
Dermatitis herpetiformis
Some skin conditions such as dermatitis herpetiformis are well researched. Reliable and consistent scientific data shows that avoiding gluten results in substantial health benefits. Dermatitis herpetiformis (DH) is an inflammatory itchy skin disease, linked to coeliac disease. It affects fewer people (1 in 3,300) than typical coeliac disease (1 in 100). The rash is most commonly seen on the elbows, knees and buttocks, but any area of the skin can be affected. It can appear at any age, but is most usually diagnosed in people who are between 50 and 70. The treatment for DH is a lifelong gluten-free diet.
This means avoiding all sources of gluten, which is found in wheat, barley and rye, and products made from those grains. Some people are also sensitive to oats. It can take an average of two years for a gluten-free diet to take full effect, and in some cases longer.
Other skin conditions have only little or some evidence linking them with specific nutrients.
Systemic
lupus erythematosus (SLE) Lupus is an autoimmune condition characterised by a butterfly-shaped rash on the face, accompanied by joint inflammation and fatigue. Preliminary studies suggest a minimal health benefit from EPA (omega 3 fats). However, there has
been an insufficient number of studies, and contradictory results. Supplements, not fish, have been used in most studies. Until more is known about the connections between EPA and SLE, many patients simply try to eat oily fish twice a week to ensure an adequate intake of omega 3 and vitamin D.
Spanish researchers have also found that patients with SLE tend to have more allergies, including food allergies, than people with other autoimmune diseases.
If you think you have allergies, it is recommended you have a consultation with an immunologist to have them medically diagnosed.
Eczema
Atopic eczema (atopic dermatitis) is an inherited skin condition more common in people with a family history of inhalant allergies such as asthma or hay fever. Patients develop weeping, oozing, itchy skin lesions. It often begins in infancy and improves in most people as they reach adulthood.
About 10 to 15 per cent of children with atopic eczema are affected by food allergens. These include: milk (cow's), eggs, nuts, soya and wheat. Foods rarely affect the symptoms of adults with eczema. See ifan.ie.
Psoriasis
An inflammatory skin condition characterised by red flaky scaly patches, psoriasis tends to come and go throughout life. Several studies looking at psoriasis and fish oil did not provide enough reliable evidence to form a clear conclusion. One study by Collier et al found that 170g of oily fish daily led to a modest clinical improvement in psoriasis. That's a fish dinner every evening.
The Department of Health currently recommends an intake of 140g of oily fish once ar week for the general population. Oily fish include mackerel, salmon, kippers, herrings, trout, sardines and pilchards. Tinned tuna is not as good a source because of losses incurred during processing.
Some studies have found that people with the highest intakes of fresh fruit, carrots, tomatoes and beta-carotene were less likely to have psoriasis. Beta-carotene is found particularly in yellow or red fruits and vegetables such as butternut squash, carrots, sweet potato and peaches.
Key to treatment
There is a strong link between eating a diet that is rich in fruit and vegetables, and a reduced risk for certain diseases, but the value of taking beta-carotene supplements has not been ascertained and may even be harmful.
Despite the lack of evidence that specific nutrients hold the key to the treatment of many common skin disorders, there are umpteen books and websites touting unproven miracle diets.
If you do notice your skin condition gets worse after eating certain foods, keep a note of it and try to identify repeated patterns with exposure to the food over time. Then discuss this with your dermatologist or doctor.
What you eat obviously influences your skin’s health and your overall health. That’s inarguable. Essential nutrients include selenium, zinc, vitamin A, C , D and E and omega 3, but supplements are probably not the way to go.
It may be that the complex matrix of constituents in foods, rather than a high intake of one particular nutrient, is beneficial for health. Nuts, olive oil, spices (turmeric and ginger), berries (blueberries, raspberries etc), greens and oily fish were all enjoyed in the traditional Mediterranean anti-inflammatory diet and underpinned with plenty of exercise. There is no need for extreme diets, enemas or fasting.
Paula Mee is a dietitian and a member of the Irish Nutrition and Dietetic Institute. pmee@medfit.ie Tweet @paula_mee
