There has been a lot of research carried out into the relationship between diet and atopic dermatitis, and it is understood that diet can play a factor in the development of the condition and as a trigger of flares.
Diet & Atopic Dermatitis
July 5, 2023
A substantial body of research has explored the link between diet and atopic dermatitis. It's recognised that diet can influence the condition's development and trigger flare-ups. However, there's no consensus on the diet-eczema relationship in adulthood, leading to a lack of specific guidelines. Here's a summary of current knowledge.
The impact of our diet on our body is complex and best understood when broken down into separate components.
1. Food allergies
2. Food intolerances
3. Supplements that impact eczema symptoms
It's crucial to distinguish between food allergies and food intolerances. Allergies are specific and measurable, confirmed through allergy testing. In contrast, intolerances are broader, often linked to food groups rather than specific foods. Currently, there's no definitive test for intolerance beyond assessing symptoms and modifying the diet to avoid suspected triggers.
1. Food allergies
The relationship between food allergies (FA) and atopic dermatitis (AD) is complex. In summary, food allergies primarily trigger AD in early childhood rather than adulthood. It's important for individuals to avoid eliminating foods from their diet without robust evidence of food-related allergic reactions.
Both FAs and AD are atopic (allergy-related) conditions that often coexist. There's evidence indicating that AD in early childhood can contribute to the development of FAs. This is because the weakened skin barrier function in individuals with eczema allows food allergens to penetrate the skin, leading to sensitisation. However, not all sensitised individuals will develop symptomatic food allergies upon further exposure.
For those who develop symptomatic allergies, re-exposure can trigger a range of symptoms, including wheezing (breathing issues), diarrhoea (bowel problems), or skin reactions such as lip swelling, itchiness, or flares of eczema. These reactions can occur immediately or be delayed, with timing varying among individuals.
Some individuals with food allergies (FAs) will experience eczema flare-ups following exposure to the allergen. This is a delayed-type reaction and typically occurs 6-48 hours after exposure. However, this pattern of FAs and eczema flare-ups is stronger in young children than in adults. Most adults sensitised to foods will not experience eczema flare-ups following re-exposure. Elimination diets, which exclude specific foods, can complicate matters further. Reintroducing excluded foods may lead to worsening reactions because regular exposure to low doses of allergens promotes tolerance, which can be rapidly lost if the allergen is fully excluded from the diet.
In young children with severe eczema or those unresponsive to treatment, screening for allergens known to provoke flares is recommended. Common food allergies include dairy products/cow's milk, egg whites, peanuts, and tree nuts. Food allergy testing is typically conducted using skin-prick tests.
2. Food intolerances
Food intolerances are more prevalent than allergies and encompass a wide array of symptoms resulting from food exposure. Often, these stem from gut bacteria issues or enzyme deficiencies. Unlike allergies, intolerances are challenging to define as there's no straightforward blood test for confirmation or exclusion. Symptoms can vary widely, including exacerbation of underlying skin problems such as inflammatory skin conditions.
Keeping a food diary and tracking symptoms against your diet can help identify potential food triggers. It's important to note that how food is cooked is just as crucial as the type of food consumed, as the chemical composition of foods changes significantly during the cooking process.
Instead of delving into detail about food intolerances, we've summarised the nutritional supplements known to affect eczema.
Role of probiotics
Probiotic foods are food products that contain live bacteria (friendly bacteria) that aid food digestion by actively breaking down foods. These can be taken either as supplements or by increasing dietary consumption of foods containing naturally high levels of probiotic bacteria (kimchi, miso, coconut kefir). The data on the benefit of these is inconclusive but some studies have shown improved eczema symptoms by increasing probiotic intake.
Role of prebiotics
Prebiotics are food supplements that are specifically chosen to increase the growth of our natural gut bacteria (think of them as bacteria boosters). Eating these supplements creates a nutrient-rich environment allowing our natural bacteria to thrive, this is thought to provide allergy-protective effects. Examples include asparagus, bananas, onions, leeks and leafy greens.
3. Supplements that impact eczema symptoms
In general, if we maintain a healthy, balanced diet, cooking and consuming whole foods (unprocessed), there's usually little need for dietary supplements as we're unlikely to have specific nutritional deficiencies. Supplements become more important when individuals have restricted diets, such as veganism, where it may be challenging to access or replace specific nutrient-rich foods.
Essential fatty acids
Omega-3 fatty acids are known for their anti-inflammatory properties and are found in oily fish, algae, flaxseed, walnuts, and canola oil. Regular consumption of omega-3 is recommended as part of a healthy diet due to its multiple health benefits. These include improved heart health, reduced risks of heart attacks, and lowered blood pressure. While the evidence supporting its benefits in atopic dermatitis is mixed, some studies have shown that regular intake may reduce itchiness and severity of the condition.
Vitamins D
Vitamin D's primary role in the body is to aid in calcium storage, yet it also contributes to infection prevention and can modulate immune reactions in the skin. Both vitamin D deficiency and atopic dermatitis (AD) are more prevalent in populations residing farther from the equator, suggesting a potential link between low vitamin D levels and AD. However, there's conflicting evidence regarding the efficacy of vitamin D supplements, with some studies indicating improvement in disease severity. This is likely beneficial only for those who are deficient in vitamin D, with risk factors including dark skin, higher BMI, and reduced sun exposure. While sunlight exposure is the primary source of vitamin D, it's essential to obtain it from the diet, especially during winter months. Foods rich in vitamin D include oily fish, mushrooms, cheese, eggs, and dark chocolate. If you suspect a vitamin D deficiency, consult your GP for a blood test to assess your levels.
4. FAQ's
How do I know if my diet triggers my eczema?
Indications that your eczema might be triggered by foods include experiencing worsened symptoms 1-2 days after consuming specific foods. The simplest way to monitor this is by tracking your symptoms daily, recording your diet, and identifying patterns between specific food types and symptom severity. If certain foods consistently lead to worsened symptoms, eliminating them from your diet can help determine if symptoms improve. However, it's crucial to note that significant food allergies driving eczema in adulthood are rare. Additionally, blood test allergy testing is often unhelpful, as confirmed food sensitisation doesn't necessarily correspond with symptomatic allergy.
Is it safe to eliminate foods from my diet?
It is generally not recommended to start excluding foods from your diet. If you have a confirmed food allergy then foods can be excluded under specialist guidance. Excluding foods outside of specialist guidance can lead to reduced tolerance to foods leading to worsening severity of allergy symptoms on future re-exposure. We'd only recommended eliminating foods if you have significant data strongly suggesting specific food triggers following a period of diet/symptom tracking.
Is there such a thing as an anti-inflammatory diet?
There has been growing attention on the impact of foods on inflammation, although there's currently no standardised definition of an anti-inflammatory diet or evidence demonstrating its efficacy in improving eczema symptoms. However, if you're interested in experimenting with your diet, here's a rough breakdown of recommended foods:
Vegetables and fruits: Aim for high consumption or a wide variety of fruits and vegetables.
Protein: Include plant-based proteins such as legumes, soy, nuts, and seeds. Also incorporate fatty fish and some lean animal protein.
Carbohydrates: Opt for whole grains in small amounts, focusing on high fibre options while reducing intake of refined sugar and carbohydrates.
Fats: Utilise olive oil as a primary fat source.
Other features: Increase intake of anti-inflammatory herbs and spices such as turmeric, garlic, and ginger.
What's the best diet for eczema?
Currently, there's no specific diet tailored specifically for eczema. However, adopting a Mediterranean diet, which closely resembles the anti-inflammatory diet described earlier, is a beneficial starting point. It emphasises whole foods (unprocessed), vegetables, fruits, and healthy fats while minimising intake of junk foods and highly processed foods.
