For whom is the nickel-free diet for?
The nickel-free diet is primarily recommended for people who have been diagnosed with a nickel allergy. This type of allergy is most often manifested by contact dermatitis (SCD) in either a local or systemic form [1,2].
With SCD, the following may occur [1,2]:
- itching,
- redness,
- blisters,
- desquamation.
These complaints occur especially in areas of skin contact with nickel. They can be triggered by jewelry or metal clothing items [1,2].
Systemic contact dermatitis manifests itself systemically. The following may occur [1,2,3]:
- skin symptoms appearing all over the body, such as rashes, itching, redness,
- generalised symptoms, such as headaches, fatigue, joint pain, digestive problems.
Another indication for a nickel-free diet is nickel food allergy syndrome. This is usually manifested by digestive complaints such as nausea, vomiting, abdominal pain and diarrhea [1,2,4].
A nickel-free diet may also be beneficial for other dermatological or autoimmune conditions. Nickel allergy exacerbates the symptoms of these diseases. Following a nickel-free diet may provide relief and improve overall health [1].
The introduction of a nickel-free diet should always be preceded by a medical diagnosis. Usually, the diagnosis consists of patch tests. Consultation with a dermatologist and a dietician is very important in developing an appropriate dietary plan [1,2,3,4].
Nickel in food – main sources
Nickel is a trace element present in many foods. Its sources include both plant and animal products. Most nickel is found in [1,4,5,6]:
- nuts: hazelnuts, almonds, cashew nuts,
- seeds: sunflower seeds, linseed, pumpkin seeds, sesame seeds,
- pulses: lentils, green beans, peas, soya beans,
- whole grain products: bran, oats, rye, brown rice,
- some fruits: kiwi, pineapple, raspberries, cherries,
- certain vegetables: spinach, tomatoes, broccoli,
- seafood: fish, shellfish,
- selected spices: basil, cinnamon, curry, nutmeg, cloves, cardamom, cumin, coriander, marjoram, oregano.
A nickel-free diet requires the elimination of these products, as well as the avoidance of other sources such as canned foods (due to metal packaging), chocolate, tea and coffee [4,5].
A nickel-free diet – is it possible?
A nickel-free diet can be difficult to implement as it is present in many foods. The amount of nickel in food depends on various factors, like among others its concentration in the soil and water or the season in which the crops are grown. This means that the same vegetables from different crops may have a different nickel content. In addition, heat treatment such as boiling, frying or baking can increase the content of this element in food. Therefore, it is nearly impossible to completely eliminate nickel from the diet [4,7].
However, the introduction of a nickel-restricted diet can benefit the wellbeing of people with hypersensitivity to this element. With a conscious choice of low-nickel products and the application of food preparation principles (as discussed below), it is possible to alleviate adverse symptoms. It is important that people with an allergy to this ingredient work together with a dietitian. This will allow the diet to be properly balanced and deficiencies to be avoided [4,7].
Products rich in nickel
Products that contain high levels of nickel should be completely excluded from the diet. These include [1,4,5,6]:
- nuts and seeds: almonds, cashew nuts, hazelnuts, sunflower, pumpkin, sesame,
- pulses: lentils, beans, peas, soya beans,
- whole grain products: bran, oats, rye, buckwheat, brown rice,
- vegetables: spinach, tomatoes, broccoli, lettuce,
- seafood: shellfish, fish, e.g. herring, tuna, mackerel,
- spices: basil, cinnamon, curry, nutmeg, cloves, cardamom, cumin, coriander, marjoram, oregano,
- other products: chocolate and chocolate products, e.g. sweets, tea, coffee, tinned foods, tomato paste, soy sauce.
Low nickel products
Safe products on a nickel-free diet are [1,4,5,6]:
- dairy products: milk, yoghurt, cheese, kefir, buttermilk,
- meat: poultry, beef, pork,
- eggs,
- some vegetables: carrots, potato, cucumber, courgetti,
- fruit and fruit juices: apples, pears, bananas, apricots, peaches,
- some cereal products: white rice, millet.
How to follow a nickel-free diet?
While on a nickel-free diet, it is useful to be aware of hidden sources of nickel. Tap water can contain significant amounts of this element, especially if supplied through stainless steel pipes. Water filters can help to reduce the nickel content in tap water. Additionally, it is important to remember that when following a nickel-free diet, it is not enough to simply avoid certain foods. Contact with jewellery, watches and other metal objects can cause skin reactions that exacerbate allergy symptoms. Therefore, it is also necessary to avoid such items or to choose safe substitutes, such as those made of glass or ceramics [4,5,7].
Following a nickel-free diet requires the observance of several important rules. First of all, avoid products with a high nickel content. It is necessary to pay attention to food labels, as nickel can be hidden in processed products. It is advisable to choose fresh meat, eggs and dairy products, which are usually low in nickel. Bottled water should be preferred to tap water, especially if the water in your region has a high nickel content. It is best to choose foods that are as little processed as possible. Food production processes often involve contact with a lot of metal machinery, equipment and containers. This can lead to nickel contamination [1,5,7].
In addition to the proper selection of food products, adequate food preparation is also extremely important. Food should be cooked in glass or ceramic pots. Steel pots may increase the amount of nickel in food. In addition, it is advisable to use plastic, wooden or bamboo cutlery. Metal cutlery, especially that made of stainless steel, contains nickel. In some cases, even a small amount released during eating can cause a reaction in a person with hypersensitivity to this element. Canned products, such as tinned foods, should be eliminated as metal packaging may contain nickel [1,5,7].
It is important that the nickel-free diet is carried out under the care of a doctor or dietician. They will support the correct balance of the diet and ensure that all the necessary nutrients are provided. Sometimes it may be necessary to supplement vitamins and minerals if they cannot be supplied in sufficient amounts with food. In addition, it is advisable to keep a food diary to monitor the foods consumed and symptoms. This may help to identify potential sources of nickel and eliminate them [1,4,5,7].
