Foods High in Nickel: Can Your Diet Worsen a Metal Allergy?

I'm Dr. Hongseok Kim, a board-certified Korean dermatologist with 21 years of practice and the medical director of VOS Dermatology Clinic in Gangnam, Seoul, in front of Dosan Park. At VOS I see every patient myself, from the consultation to the treatment.

People who know they react to metal often ask whether foods high in nickel could explain itching that never quite settles. For a small group, they can, and some of those foods are staples of the Korean table. This page is based on my YouTube video from July 2024; I rewrote it for readers abroad. The video above can be watched with translated captions.

What a nickel allergy is

If earrings, necklaces, rings or a jeans button leave your skin itchy, red or oozing, that is usually allergic contact dermatitis to nickel (in the video at 00:32).

Metal allergy is one of the most uncomfortable allergies in daily life. Gold- and silver-plated items often use nickel alloys to make the finish shinier, and nickel causes allergic contact dermatitis very often (in the video at 00:59). Overseas figures usually cite around 15 to 20%, while in Korea the rate is reported at around 30 to 35% (in the video at 01:12). When we apply the Korean standard patch-test series to people's backs, roughly three in ten react (in the video at 01:25). The round metal button on the back of jeans, which presses against the belly all day, is a classic spot; many people come in with redness there, and some with dark pigmentation (in the video at 01:37).

Why avoiding contact is the main fix

There is only one real solution: avoid the cause, for example by covering a jeans button with fabric so it doesn't touch the skin (in the video at 01:51).

The moment your body starts treating a harmless substance as an allergen is called sensitisation (in the video at 02:04). After that, it keeps reacting every time, and the problem usually lasts for life, so it pays to remove the cause clearly (in the video at 02:18).

Foods high in nickel

Beans, coffee beans and cocoa are high in nickel; in Korea the dishes that matter most are soybean-based stews eaten every day (in the video at 03:49).

Data in Korean dermatology journals show that about 1% of people with nickel contact allergy can develop a whole-body contact dermatitis even from small amounts of nickel in food, and about 10% when they eat large amounts (in the video at 02:32). Nickel is abundant in soil. Nitrogen-fixing plants turn nitrogen from the air into usable compounds with the help of enzymes such as urease, and nickel plays a key role in that enzyme, so these plants end up rich in nickel (in the video at 03:15).

The representative food is the bean, especially the soybean. Coffee beans and cocoa beans, from which chocolate is made, are also high (in the video at 03:49). In Korea, soybeans are fermented into meju, which becomes the base of doenjang stew and cheonggukjang, and these are high in nickel (in the video at 04:07). Ingredient for ingredient, coffee and chocolate rank higher, but nobody eats coffee like soup every day. Staples are eaten in much larger portions, so in practice doenjang stew accounts for a large share (in the video at 04:20). Stews that combine soybeans or tofu, kimchi stew included, add to it (in the video at 04:48).

What to cut back, and how

If you react, reduce soybean dishes and brewed coffee rather than trying to remove everything (in the video at 05:45).

People with nickel allergy know how miserable the itch is: a couple of mosquito bites are bad enough, and an itch spread over the whole body without a clear cause is much worse (in the video at 05:19). Papers have reported that when people with this allergy changed their intake of high-nickel foods, their symptoms improved noticeably (in the video at 05:31). The difficulty is that these are everyday foods; cutting out doenjang and kimchi stews entirely is almost impossible. So reduce soybean-based dishes, for example by having doenjang stew or tofu less often, and cut back on brewed coffee such as americanos to an amount you can control (in the video at 05:58). That can lower how often flare-ups happen.

Why patch testing isn't done every time, and how to test at home

A two-week trial of cutting back can suggest a nickel allergy, but only a patch test confirms it (in the video at 07:10).

Patch testing is hard on patients: the patches stay on for two to three days, you come back to have them removed and you can't wash in the meantime (in the video at 06:21). Even with a result, it is often hard to apply in daily life, so many doctors don't order it routinely (in the video at 06:33). I'm not saying beans cause allergy (in the video at 07:03). But if you keep getting itchy, eczema-like patches without a known cause, try limiting these foods for about two weeks. If the symptoms ease a lot, you can reasonably suspect a nickel allergy. Confirmation still requires a patch test, and fewer clinics offer it now, so it isn't always easy to arrange (in the video at 07:24). My page on choosing a Korean dermatologist covers what to ask before a visit, and the treatments at VOS list what the clinic offers. Our creator experiences at VOS show how visitors planned their appointments.

Results vary from person to person, and whether diet plays a part in your symptoms is decided with a dermatologist at an in-person consultation.

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Results, swelling and recovery vary from person to person. This page is general information from VOS Dermatology Clinic based on Dr. Kim's video and does not replace an in-person consultation.