Nickel is a naturally-occurring metal and is found in abundance in both the earth’s crust and core. It has a variety of industrial applications but over two-thirds of global output goes toward the production of stainless steel.
Nickel allergy is common with some estimates placing the prevalence at 18% in North America. A patch test can be used to conclusively diagnose an allergy to nickel.
In affected people, nickel allergy is a common cause of allergic contact dermatitis and dyshidrotic eczema. If you develop a rash your doctor may recommend replacing certain everyday items with hypoallergenic alternatives.
Jewelry, piercings, watchbands, and eyeglass frames are just some of the products that may expose you to nickel.
Some affected people follow a low-nickel diet aimed at minimizing the consumption of foods with high nickel content. Although nickel cannot be entirely avoided, it is possible to reduce the dietary intake of the metal through careful planning.
What is a Low-Nickel Diet?
Nickel is widely present in both plant and animal foods and therefore total avoidance of the metal is hard to achieve. However, plant foods, in general, have higher nickel content than meat and dairy products (1).
A low-nickel diet can be accomplished by carefully selecting foods with lower concentrations of nickel and by eliminating or reducing consumption of foods that typically have high nickel content.
The amount of the metal present in soil samples varies widely. However, nickel is considered an essential micronutrient in plant development (2).
Another form of exposure to nickel can stem from the use of stainless steel cookware (3). Switching to cast iron or ceramic utensils can help reduce nickel exposure (4).
Research suggests that most cooking with stainless steel utensils releases very little nickel into food. However, preparing acidic foods with this cookware can increase nickel content (1).
How Well Does The Diet Work?
Firstly, a low-nickel diet is usually proposed alongside other interventions after a nickel allergy is diagnosed. A key preventative measure is to minimize contact with objects containing nickel.
A low-nickel diet is often used in people with a particularly acute sensitivity to nickel and who are still experiencing symptoms after reducing their exposure to nickel-containing items (5).
Nickel is a major cause of allergic dermatological issues and a low-nickel diet is one approach that has generated interest from researchers. Oral intake of nickel has been shown to provoke and/or worsen hand eczema in nickel-sensitive patients (6).
A study of 204 patients with confirmed nickel allergy found significant improvements in dermatitis following 1 to 2 months of a reduced-nickel diet (7).
Another study followed 90 nickel-sensitive patients on a similar diet. 58 people saw a definitive improvement in their dermatitis and a further 15 had “possible improvement”. In a follow-up questionnaire 1-2 years later, 40 out of 55 patients who responded to initial treatment reported a long-term improvement in their dermatitis (5).
Interestingly, patients with the most strongly positive patch test result saw less benefit from the diet than those with a more moderate reaction. This suggests that people with the strongest sensitivity to nickel respond less well to dietary interventions.
Other research teams have suggested that dietary nickel may be the underlying cause of allergic dermatitis in some patients with a contact nickel allergy (8).
Following A Low-Nickel Diet
A low-nickel diet plan may help some individuals with a confirmed allergy. However, you should consult with your doctor before making any radical changes to your diet.
Nickel is present in soil and so many plant-based foods contain trace quantities of the metal. However, animals (and animal foods) also contain small quantities of nickel acquired through their own diet.
Relatively high-nickel foods include:
- Whole wheat
- Whole grain
- Soya beans
- Nuts & Seeds
- Sunflower seeds
- Raw carrots
- Green leafy vegetables (particularly older leaves)
- Canned foods (due to leaching)
- Dried fruits
- Red kidney beans
- Baking powder
- Certain vitamin supplements
Relatively low-nickel foods include:
- Animal foods
- Cow’s milk
- Fish (with the exception of those listed above)
- Other dairy
- Polished rice
- Refined wheat
- Green leafy vegetables (preferably younger leaves in moderation)
- Citrus fruits
The absorption of dietary nickel into the bloodstream can be affected by several factors. For instance, although tea and coffee can have high nickel content, both can actually inhibit nickel absorption. The same is true of Vitamin C, orange juice, and milk (9).
Pregnancy and lactation can increase nickel absorption, as can iron deficiency anemia. Meanwhile, sufficient iron intake can help reduce the absorption of dietary nickel (10, 11).
The effectiveness of a low-nickel diet can vary from one location to another, and even from one season to the next. Plant tissues have been observed to contain more nickel in spring and autumn than in summer (12, 13).
In addition, nickel concentration varies in different parts of the same plant. Leaves generally contain more nickel than stems and roots, and older leaves tend to contain more nickel than younger leaves (14).
Although the aim of a low-nickel diet is to reduce the severity of contact dermatitis, flare-ups still may occur. Nevertheless, successful interventions can help symptoms to become milder and less frequent.
Other Treatment Approaches
Preventive measures against nickel-induced allergic dermatitis also include minimizing exposure to nickel-containing products. Avoiding nickel products can be more difficult than it seems because of the huge number of items that contain the metal.
Nickel-free jewelry, watchbands, zippers, and eyeglass frames can go a long way to reducing exposure. If contact with nickel products is unavoidable then you may consider creating a barrier between the item and your skin (e.g. by wearing gloves).
Another approach is to cover items such as belt buckles, tools, and zippers with duct tape or a specialist product like Nickel Guard. Electronic devices have also been linked to allergic contact dermatitis.
Many people experience flare-ups in their condition that come and go intermittently. Your doctor may prescribe a corticosteroid or nonsteroidal cream to apply to the affected area. In some cases, an oral corticosteroid or antihistamine may be used (15).
Although dermatological issues can cause some distress, it is possible to minimize and control symptoms with careful planning and proper medical treatment.