What is Nickel?
Nickel is a metal, it’s naturally occurring in our environment, it’s the 5th most common element on earth found in earth’s crust and core, and it’s common in meteorites. (1)
Our modern way of life has increased our exposure to nickel. It’s found everywhere in the environment, it’s used often in jewelry, coins, cell phones, dental materials, cooking utensils, medications, and supplements. (1)
Cosmetic products can contain nickel too, and when used on thinner skin, like the eyelids, there can be an increase in absorption of it, causing reactions at relatively low levels in people that are allergic or sensitive to it.
Because it’s found in the earth, it finds its way into soil and water, which means it makes its way into our food. (2)
Nickel allergy, and nickel allergy statistics
Metal allergy is an inflammatory, delayed-type hypersensitivity reaction. This means it happens more than 12 hours after exposure. (3) Some people get skin reactions from brief exposure, and others only develop an allergy after long-term contact with nickel. Hives, which is a type 1 hypersensitivity response (these are immediate reactions, mediated by IgE immune responses), may result from dietary exposure to nickel. (4)
People of any age can be affected. Reactions to metals like nickel typically result in contact dermatitis, so we see a reaction where the allergen had contact with the skin. It’s rare according to the literature that a rash develops in an area other than where the nickel was in contact with the skin, which doesn’t mean that it doesn’t happen! (4)
Sometimes reactions are systemic, which means nickel causes a reaction through the circulatory system. This can result in widespread rashes, anywhere on the body. This can happen when someone that’s sensitized or allergic to nickel is exposed to it in food, cosmetics, medications, supplements, and even in dental materials like braces. Nickel allergy can result in dyshidrotic eczema, which is that blistery hand eczema, and the hands are the body part most often involved with systemic nickel dermatitis. (5–8)
About 10%–15% of the population has contact hypersensitivity to metal. (9,10 )
Nickel allergy is more common in women than men. It’s found in about 10% in women vs. 2% in men. (11,12)
Women are sensitized more often by non-work-related exposures like ear piercing, wearing jewelry containing nickel, and using cosmetics that contain it. Most men get sensitized via exposure at work, so men that work in industries that involve metals are at a greater risk. (13)
People with autoimmune conditions have an increased prevalence of metal allergy. (14)
Hairdressers have a high prevalence, up to 27-38%. (15)
In nickel allergy, ions get released from the nickel, and they are strong allergens. They can penetrate the skin, trigger skin inflammation, and activate immune cells in the skin that release various chemical messengers. This process can sensitize someone to nickel so that future exposure to it can cause allergy symptoms, and once sensitized, the sensitization tends to continue for life. (13)
Symptoms of nickel allergy
Some people react to nickel through the diet, but most often, symptoms of nickel allergy result from touching the metal. The skin allergy causes contact dermatitis, and symptoms like redness, irritation, inflammation, or rashes. Some people experience systemic symptoms, like headache, stomachache, and respiratory problems. (2)
How to test for nickel allergy
Metal allergy is mainly diagnosed by patch testing. (13) A short-term elimination diet, and avoiding environmental exposure to it, may also help determine if nickel is problematic.
Nickel allergy and cobalt allergy (and B12)
Reactions to nickel are more common than to cobalt, but the two can be linked. Cobalt allergy is often found to coexist with nickel allergy. (6) Vitamin B12 contains cobalt in its structure so it’s possible that someone allergic to cobalt could react to B12 supplements. This doesn’t occur with food sources of B12. Vitamin B12 is found naturally in aminal foods.
Diet for Nickel allergy
The amount of nickel that gets absorbed in the gut affects how much ends up in the body. While about 25% of the nickel found in drinking water (for example) gets excreted in the urine, only about 1% gets absorbed. (16) Because genetics play a role too, some people end up with greater absorption of nickel (and/or other metals) compared to others. (13)
Someone may be more likely to develop a nickel allergy if other people in the family are allergic or sensitive to nickel, or to other metals. (17)
Nickel is found in most foods, and food is considered to be a major source of nickel exposure. (4)
How does nickel get into our food? Plants get it from the soil they grow in. Animals get it from plants and other animals they eat. Humans get it from plants and animals they eat. Levels of nickel in the soil strongly determine the levels of nickel foods, and the soil differs from place to place. Things that influence nickel levels in the soil include agriculture, the use of synthetic fertilizers, and pesticides, and contamination with industry and urban waste. (4,6)
Plants contain four times more nickel than animals, so the total dietary intake of nickel per day depends on how many plant and animal foods someone eats. (4)
Because levels in the soil differ from place to place, some foods in some places may be higher in nickel than the same foods in other places. (4,6)
Since nickel is in so many foods it’s impossible to remove it completely, so avoiding foods higher in nickel that are eaten often can help with symptoms. (4,6)
Some foods have higher levels of nickel regardless of the soil content (4)
Whole wheat
Whole grain
Rye
Millet
Buckwheat
Tea
Gelatin
Baking powder
Red kidney beans
Legumes (peas, lentils, peanut, and chickpeas)
Dried fruits
Canned foods and beverages
Other foods that contain a considerable amount of nickel (4)
Beer
Red wine
Mackerel, tuna, herring, and shellfish
Sunflower seeds
Hazelnuts
Walnuts
Tomatoes
Onion
Raw carrots
Processed foods can contain higher concentrations of nickel. This is free nickel, picked up from the stainless steel used in manufacturing the foods. Cooking acidic foods (i.e. tomato-based and citrus foods) in stainless cookware can increase the nickel content in the food because acid promotes the release of nickel from the cookware. (4)
A dietary requirement of 25-35 μg of nickel per day has been suggested, but the role of nickel in the body isn’t clear. (4)
The concept of a low nickel diet
Because nickel is everywhere, it’s impossible to completely remove it from the diet (so please don’t try!). Lowering intake and minimizing exposure can help.
If you suspect a nickel allergy, see your doctor, get tested, and confirm it. If you aren’t sure don’t assume. I do not recommend diet restrictions that aren’t necessary, so test, don’t guess! Limited diets are a recipe for disaster when they aren’t necessary.
Points to consider with a low nickel diet:(4)
Because the content of nickel in foods varies from place to place, the benefits of a low nickel diet will vary from person to person.
Avoid foods commonly high in nickel.
Avoid beverages and vitamin supplements with nickel, and canned foods.
Animals generally contain less nickel than plants. Plants have more nickel in spring and fall, but lower levels in the summer months. Plant leaves have more nickel than the root and stem. Old leaves have more nickel than younger leaves.
Avoid high nickel fish like tuna, herring, shellfish, salmon, and mackerel.
The nickel content of milk and milk products like butter, cheese, and cottage cheese is low.
Vegetables including potatoes, cabbage, and cucumber can be eaten.
Onion and garlic should be used in moderation.
Bananas, apples, and citrus are ok, in moderation.
Tea and coffee can be high in nickel.
Avoid using nickel-plated utensils when cooking.
Acidic food should not be cooked in stainless steel.
The initial water flow from the tap in the morning should not be drunk or used for cooking because nickel may be released from the tap during the night.
While a low nickel diet typically doesn’t completely resolve the problem, it can lead to fewer and more mild symptoms and flares. (4)
Other things that impact nickel absorption from the diet (4)
Vitamin C and vitamin C-rich foods like orange juice and citrus fruits can inhibit nickel absorption. (18)
Iron Deficiency Anemia can increase nickel absorption in the body. (19)
Adequate iron intake and status can lower nickel absorption from the diet. (20) Foods rich in iron are animal foods (dark meats have more iron than light and white meats), raisins, prunes, potato with skin, quinoa, spinach, lentils, tofu, hazelnuts, cashews (yes some of these are going to contain nickel too, it can’t be avoided completely!).
Vitamin C enhances iron absorption (eat it with iron-rich foods).
Calcium inhibits iron absorption (have it away from iron-rich foods).
Four suggestions for addressing nickel allergy
If you suspect nickel allergy, talk to your doctor and get tested.
Try an elimination diet, short-term only (a month) to see if it helps. If not, don't blame nickel. Add those foods back in.
If a low nickel diet helps, you may be able to desensitize with nickel sulfate. (21) Talk to your doctor about it, it's not do-it-yourself!
Probiotics combined with a low nickel diet in those with nickel allergy may help with skin symptoms. (22)
References
1. The Nickel Institute. About nickel. Accessed July 22, 2021. https://nickelinstitute.org/about-nickel/
2. WebMD. Foods High in Nickel. Accessed July 22, 2021. https://www.webmd.com/diet/foods-high-in-nickel#:~:text=The%20level%20of%20nickel%20in,high%2Dnickel%20foods%20to%20avoid
3. Marwa K. Type IV Hypersensitivity Reaction. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK562228/
4. Sharma A. Low nickel diet in dermatology. Indian J Dermatol. 2013;58(3):240. doi:10.4103/0019-5154.110846
5. Pigatto PD, Guzzi G. Systemic allergic dermatitis syndrome caused by mercury. Contact Dermatitis. 2008;59(1):66. doi:10.1111/j.1600-0536.2008.01361.x
6. Yoshihisa Y, Shimizu T. Metal Allergy and Systemic Contact Dermatitis: An Overview. Dermatol Res Pract. 2012;2012:1-5. doi:10.1155/2012/749561
7. Yokozeki H, Katayama I, Nishioka K, Kinoshita M, Nishiyama S. The Role of Metal Allergy and Local Hyperhidrosis in the Pathogenesis of Pompholyx. J Dermatol. 1992;19(12):964-967. doi:10.1111/j.1346-8138.1992.tb03813.x
8. Song H, Yin W, Ma Q. Allergic palmoplantar pustulosis caused by cobalt in cast dental crowns: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endodontology. 2011;111(6):e8-e10. doi:10.1016/j.tripleo.2010.12.013
9. Loh J, Fraser J. Metal-derivatized Major Histocompatibility Complex. J Exp Med. 2003;197(5):549-552. doi:10.1084/jem.20022180
10. Büdinger L, Hertl M, Büdinger L. Immunologic mechanisms in hypersensitivity reactions to metal ions: an overview. Allergy. 2000;55(2):108-115. doi:10.1034/j.1398-9995.2000.00107.x
11. Peltonen L. Nickel sensitivity in the general population. Contact Dermatitis. 1979;5(1):27-32. doi:10.1111/j.1600-0536.1979.tb05531.x
12. Nielsen NH, Menné T. Allergic contact sensitization in an unselected Danish population. The Glostrup Allergy Study, Denmark. Acta Derm Venereol. 1992;72(6):456-460. doi:102340/0001555572456460
13. Saito M, Arakaki R, Yamada A, Tsunematsu T, Kudo Y, Ishimaru N. Molecular Mechanisms of Nickel Allergy. Int J Mol Sci. 2016;17(2):202. doi:10.3390/ijms17020202
14. Stejskal V, Reynolds T, Bjørklund G. Increased frequency of delayed type hypersensitivity to metals in patients with connective tissue disease. J Trace Elem Med Biol. 2015;31:230-236. doi:10.1016/j.jtemb.2015.01.001
15. Walle HB van der, Brunsveld VM. Dermatitis in hairdressers: (I). The experience of the past 4 years. Contact Dermatitis. 1994;30(4):217-221. doi:10.1111/j.1600-0536.1994.tb00647.x
16. Sunderman FW, Hopfer SM, Sweeney KR, Marcus AH, Most BM, Creason J. Nickel Absorption and Kinetics in Human Volunteers. Exp Biol Med. 1989;191(1):5-11. doi:10.3181/00379727-191-42881
17. Mayo Clinic. Nickel Allergy. Accessed July 22, 2021. https://www.mayoclinic.org/diseases-conditions/nickel-allergy/symptoms-causes/syc-20351529
18. Patriarca M, Lyon TD, Fell GS. Nickel metabolism in humans investigated with an oral stable isotope. Am J Clin Nutr. 1997;66(3):616-621. doi:10.1093/ajcn/66.3.616
19. Tallkvist J, Bowlus CL, Lönnerdal B. Effect of Iron Treatment on Nickel Absorption and Gene Expression of the Divalent Metal Transporter (DMT1) by Human Intestinal Caco-2 Cells: NICKEL ABSORPTION AND GENE EXPRESSION OF DIVALENT METAL TRANSPORTER. Pharmacol Toxicol. 2003;92(3):121-124. doi:10.1034/j.1600-0773.2003.920303.x
20. Roy CN, Enns CA. Iron homeostasis: new tales from the crypt. Blood. 2000;96(13):4020-4027.
21. Tognon G. Nickel Allergy Diagnosis and Desensitization. Published January 31, 2021. Accessed July 22, 2021. https://www.gianlucatognon.com/nickel-allergy-diagnosis-and-desensitization/
22. Randazzo CL, Pino A, Ricciardi L, et al. Probiotic supplementation in systemic nickel allergy syndrome patients: study of its effects on lactic acid bacteria population and on clinical symptoms. J Appl Microbiol. 2015;118(1):202-211. doi:10.1111/jam.12685