Patients with eczema and a systemic metal allergy, such as to nickel (Ni), cobalt (Co), chromium (Cr), and tin (Sn), often experience a symptomatic exacerbation from excessive metal intake in food. Dietary intervention can significantly impact clinical symptoms in these patients. This article explores the role of a low-cobalt diet and other dietary modifications in managing systemic metal allergies, providing guidance on foods to eat and avoid.
Understanding Systemic Metal Allergy
The Contact Dermatitis Guideline Committee of the Japanese Dermatological Association has issued guidelines stating that dermatitis may occur over the whole body when the same antigen enters an organism through a non-percutaneous route (e.g., orally, through inhalation, or injection) after contact sensitization. This condition is commonly known as a systemic metal allergy. Common metal allergens include nickel (Ni) sulfate, cobalt (Co) chloride, and potassium dichromate.
In treating metal allergies, avoiding related antigens, including transcutaneous contact, is essential. When symptoms do not improve, restricting metal intake through diet should be considered. The ingestion of trace elements in the diet and corresponding metal intake through mucous membranes of the oral cavity or digestive organs can lead to various types of dermatitis in patients with whole-body metal allergies.
The Role of Dietary Intervention
A study involving 44 patients with cutaneous symptoms diagnosed with metal allergies showed the effectiveness of dietary metal intake reduction in controlling dermatitis. Patients were randomly assigned to a dietary intervention (DI) group instructed by a registered dietitian or a control group (C group). The DI group received individual guidance on implementing a metal-restricted diet and were evaluated one month later.
The DI group exhibited decreased intake of Ni, Co, Cr, and Sn, along with improved scores in the Severity Scoring of Atopic Dermatitis (SCORAD) index, including eczema area, erythema, edema/papulation, oozing/crust, excoriation, lichenization, and dryness. The C group, however, only showed decreased Ni and Sn intake and an improved oozing/crust score.
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Cobalt in the Body and Diet
Cobalt is a vital trace mineral required by the human body, primarily as part of cobalamin, or vitamin B12. It is involved in red blood cell synthesis, nervous system activity, sugar breakdown, energy metabolism, thyroid hormone regulation, and iron absorption. Since the body cannot synthesize cobalt, it must be obtained from food.
The metal intake level in Japan for Co is generally 7-10 μg/day. There have been no reports of results for Co in Japan, but Co levels have been reported in the USA and India.
Foods to Avoid on a Low-Cobalt Diet
For individuals with a cobalt allergy or sensitivity, avoiding foods high in cobalt is essential to manage symptoms. While specific cobalt content can vary based on soil and environmental factors, some foods are generally higher in cobalt than others. According to Dr. Matiz, patients should particularly avoid Brazil nuts, cow liver, and homeopathic/herbal remedies.
Here's a list of foods that may contain higher levels of cobalt and are often recommended to be limited or avoided on a low-cobalt diet:
- Legumes: Chickpeas, lentils, peanuts, and soybeans (including soy products like tofu).
- Nuts and Seeds: Brazil nuts and flaxseeds.
- Organ Meats: Liver and other organ meats.
- Grains: Whole grains, including wheat, oats, and buckwheat.
- Dairy Products: Milk and other dairy products.
- Cocoa and Chocolate: Due to the fat content in cocoa beans, which can increase the potential reaction with nickel.
- Vitamin B12 Supplements: Since cobalt is a main component of vitamin B12.
- Homeopathic/Herbal Remedies: Some of these may contain cobalt.
It’s also important to consider that nickel and cobalt allergies often coexist, so individuals may need to manage their intake of both metals.
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Foods to Include on a Low-Cobalt Diet
While following a low-cobalt diet, it's crucial to ensure you still receive adequate nutrition. Many foods are naturally low in cobalt and can be included in your diet.
Here are some food options that are generally considered safe for those on a low-cobalt diet:
- Fruits: Most fruits, including pears, strawberries, apples, grapes, and most berries, are safe to eat. However, raspberries and bananas should be eaten in moderation.
- Root Vegetables: Potatoes, carrots, beets, sweet potatoes, and onions contain only trace amounts of nickel and are safe to eat for those with sensitivities.
- Meats: Non-seafood meats like beef, chicken, sausage, and ham contain low amounts of nickel.
- Polished Rice: White rice is typically polished and safe to eat.
- Corn: Cornmeal, corn tortillas, cornflakes, or cornstarch can safely replace wheat or grains.
Additional Dietary Considerations
- Low-Nickel Diet: Since cobalt and nickel allergies often coexist, consider adopting a low-nickel diet as well. This involves avoiding foods like whole grains, legumes, nuts, seeds, seafood, chocolate, and certain fruits and vegetables.
- Elimination Diet: If you're unsure about your specific triggers, an elimination diet may help. This involves removing potential food triggers from your diet for a period and then slowly reintroducing them one at a time to monitor symptoms.
- Anti-Inflammatory Diet: Emphasize fruits, vegetables, legumes, healthy fats, and fish high in omega-3 fatty acids to reduce overall inflammation in the body.
- Mediterranean Diet: This diet emphasizes whole foods, plant-based foods, and lean protein over processed foods, which can be beneficial for managing eczema symptoms.
- Dyshidrotic Diet: If you have dyshidrotic eczema, limiting foods containing nickel and cobalt may help reduce flare-ups.
Study Findings: Impact of Dietary Intervention
The dietary intervention (DI) group in the study showed significant improvements in various eczema symptoms after one month. These improvements included a decrease in eczema area, erythema, edema/papulation, oozing/crust, excoriation, lichenization, and dryness. The total SCORAD (B) score and total SCORAD scores also improved.
The rate of improvement in the total SCORAD score was significant in the DI group compared to the control group for patients allergic to Ni, Co, Cr, and Sn. These findings highlight the importance of a registered dietitian's guidance in managing dietary metal intake for patients with systemic metal allergies.
Importance of Professional Guidance
Dietary guidance for patients with metal allergies is often provided by a doctor during consultation. However, consulting with a registered dietitian can provide more specific and tailored advice. A dietitian can help you understand which foods to avoid and suggest suitable alternatives to ensure a balanced and nutritious diet.
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In the study, the dietary intervention program involved detailed meal records and calculations of nutritional and metal intake using specialized software. Dermatologists used a conventional list of metal-rich foods and provided patients with instructions. The registered dietitian provided guidance for all these materials.
Practical Tips for Following a Low-Cobalt Diet
- Read Food Labels: Always check food labels for potential sources of cobalt, especially in processed foods and supplements.
- Cook at Home: Preparing your meals at home allows you to control the ingredients and avoid hidden sources of cobalt.
- Use Alternative Cookware: Avoid using cookware that may contain nickel or cobalt, such as some stainless-steel pots and pans. Opt for glass, ceramic, or titanium cookware instead.
- Stay Hydrated: Drink plenty of water to help flush out toxins and support overall health.
- Monitor Your Symptoms: Keep a food diary to track your meals and any symptoms you experience. This can help you identify specific trigger foods.