Nickel allergy is estimated to affect 10 to 20% of the general population. For most of these people the allergy is a contact allergy, where exposing the skin to nickel results in a nasty rash. This is known as allergic contact dermatitis, or ACD. Exposure to high levels of nickel through eating certain foods – a systemic route – results in dermatitis in a subset of patients with nickel ACD; frequently it presents as hand dermatitis, but sometimes it's widespread, and sometimes it's localized, appearing only in places where there has already been an ACD reaction. This is known as systemic contact dermatitis, or SCD. Nickel SCD can also be brought on by other systemic routes such as breathing nickel fumes or dust, or exposure to nickel in medical implants or dental materials.
Systemic nickel allergy syndrome (SNAS) is a broader form of nickel SCD that affects much more than just the skin, with symptoms primarily associated with the gastrointestinal and respiratory systems, along with observations of headache, dizziness, fever, cystitis, and many symptoms consistent with fibromyalgia and chronic fatigue syndromes. In fact, it's been found that some people with SNAS don't suffer from systemic dermatitis at all. Since SNAS is only beginning to be recognized outside of the realm of dermatology, it isn’t possible to speculate on how common it truly is. Some researchers estimate that SNAS occurs in under 10% of people with a nickel allergy, while others found over 60%.
If you've been directed to reduce your exposure to nickel in food, you've probably noticed that:
The Rebelytics Low Nickel Diet helps with both of these problems. For the first, we collected data on the nickel content of foods from over 200 published sources around the world, including national food studies and research papers. From this data we can compute a weighted average so that the most geographically relevant studies are given priority, which reflects the potential local variations in food sources, processing and food preparation methods. For the second, we used this larger and more diverse data with an existing scoring system in which the amount of nickel in a food is converted from a per-kilogram basis to a per-serving basis. A number of points per serving is then assigned:
Total nickel consumption is limited to 15 points, or the recommended 150 μg, daily. Anything above 10 points per serving should be avoided. The food scores are presented on colour-coded Score Sheets using a traffic light system (green, yellow, red) to make the low nickel (1 point), moderate nickel (2 points) and high nickel (3 or more points) foods easy to recognize, in an easy-to-follow low nickel diet guide.
This information has been made available to help treat a medical condition. Please do not proceed until you have medical evidence of a nickel allergy through patch testing or blood testing, or have otherwise been instructed by your doctor to trial a low nickel diet. See the Resources section for information on how to get tested.
Why get tested? First, most metal objects are blends of multiple metals. If you suspect SNAS based on your reaction to jewelry or household metals, for example, and you haven't been tested, how can you be sure which metal you're reacting to? Nickel is the most common metal allergen, but you could be allergic to any of them. You need all the facts before making important health decisions. If you're looking at a low nickel diet for a child, you have to be 100% certain it's worth the risk since it is not generally recommended for children.
Getting tested will do more than confirm your nickel allergy. You'll also find out whether you have any other allergens that could be contributing to your symptoms. It's not uncommon to have more than one contact allergy, and nickel isn't the only one found in food. If you're still reacting to an unknown allergen you won't be able to tell if the diet is working. See the first paragraph of the Other Allergies section for more.
It can take up to 3 months, or sometimes longer, to know whether the diet is working. (See When will I feel better? for more on that.) That's a long time commitment. Aside from risking the frustration of yet another failed diet attempt, there's also risk of developing nutritional deficiencies even in that short time if it's too restricted, and more so in the long-term. If you have a lot of other dietary restrictions, we recommend consulting with a dietician for nutritional advice.
Most importantly, in order to get tested you'll have to involve your doctor and you'll have the opportunity to discuss whether this diet carries any risks for your health conditions. Although a low nickel diet is generally a low-risk treatment option for SNAS, there are real risks that shouldn't be taken lightly. Talk to your doctor first to find out if a low nickel diet is an appropriate treatment option.
Score Sheets have been made for various locations around the world, and one from a global perspective (where the data isn’t weighted by location). Choose the Score Sheet for the location closest to you. All of the sheets are also available within the Excel workbook so that you can customize them if you feel so inclined. Don't forget to sign up for update notifications.
NOTE: This diet is intended only for individuals with a diagnosed nickel allergy. If you have not been patch tested or had a blood test to diagnose your nickel allergy, please do so before starting this diet. (See Before You Begin.) It is your responsibility to obtain personalized advice from a medical professional to ensure that your health needs are met.
For adults, the goal is to stay at or below 15 points per day. Pay close attention to serving sizes. We recommend using a kitchen scale until you get used to estimating serving sizes. In the Score Sheets, blue foods are essentially free, green foods cost 1 point, yellow foods 2 points, and red foods 3 or more points. You're more likely to win (eat more) if you stick to the blue and green foods. Red foods should typically be avoided so that you can fit a wider variety of foods into your daily allotment and maximize the nutrition your body needs to heal. Foods are ordered from lowest to highest average nickel score.
An asterisk (*) beside a food's label on the score sheet means that there is only one measurement available for this food. Be suspicious of these: there is often a wide variation in nickel content and this single measurement could be on the very low or very high side of the average. Beside the average score, the range of scores is given in brackets to give you an indication of how high a score can get, but be aware that the likelihood of a sample having the highest value is generally small.
"Prepared" meats, fish and vegetables are separated from raw because both the cooking method and equipment affect the nickel content. If someone else is doing the cooking, e.g. when you're eating out, use the "prepared" score. If you are preparing the food yourself with low nickel equipment, use the regular score.
If you want to have a better look at the statistics for a food, look it up in the summary tables or download the Nickel Navigator app. See Nickel in Foods for an analysis of the trends in nickel content by food group.
The rest of this page contains lifestyle advice based on published science, where it is available. Click on the blue "⌕" to see where it came from. In the event that your medical team's advice differs, theirs must take precedence. Science is awesome, but it is based on statistics whereas your medical team's advice is personalized to you. Where there is no science, we have included suggestions based on observations in online support communities. Do not take them as absolute truth, however, as we are learning more about navigating a low nickel lifestyle every day.
There are 4 main areas to consider to minimize your nickel exposure (in no particular order):
Depending on your reaction threshold, you might not have to do everything on this list before your symptoms improve, and you might not have to go to extremes in any one category. Consult your doctor if you need help deciding which category should take priority for you.
Water is important to our built-in detoxification systems, but it is also a potential source of nickel exposure. Whether your water comes from a municipal source or a well, it would be wise to get a hold of any available testing data. City water testing is often available online. Your plumbing may contain nickel, especially in older homes. It’s a good idea to allow your water to run for a few minutes every morning to flush out any stagnant water that may have collected nickel overnight. If you have concerns about the nickel content of your water supply or your pipes and faucets, you might want to consider drinking bottled water that has been nickel-tested or investing in a water filtration system. Bottled water manufacturers sometimes release their test results online, or you may need to contact them directly.
When you read a water quality report, pay attention to the detection limit or reporting limit. When the amount of nickel is reported to be "none detected", what they really mean is "it's something less than this limit". For example, in the 2020 Nestle Pure Life Water Analysis Report the Minimum Reporting Limit (MRL) was 0.01 mg/L, and the amount of nickel was "ND" or "Not detected at or above the MRL". Based on this, the amount of nickel in a 500 mL serving could be anything from 0 to 5 μg. Since the primary concern in water quality testing is toxicity, the detection limit is sometimes not a very useful value and you'll need to get your water tested privately. When you do, be sure to ask them about their detection limits also.
Studies have shown that we absorb significantly more nickel when it is taken in water on an empty stomach, as compared to taking it after scrambled eggs, and that other beverages interfere with our uptake of nickel, such as milk, juice, coffee and tea. Therefore it may be helpful to take a little food with your water, or drink it along with another beverage.
Older hot water tanks may be a problem if their sacrificial anode has corroded away. The sacrifical anode is a piece of metal that is designed to corrode before any other metal in the tank. When it is gone, other nickel-containing parts of the tank may corrode into the water, increasing its nickel content. A service provider can replace the sacrificial anode. Tankless heaters may be a nickel risk if the pipes in which the water is heated are made of a nickel-containing alloy. Contact the manufacturers to learn more.
The equipment you use in your kitchen can introduce nickel into your food that otherwise wouldn’t be there, including pots and pans, bakeware, cutlery, and food preparation equipment. Acidity, heat and exposure time contribute to the amount of nickel that leaches out during cooking, among other factors.
Many low nickel diets recommend avoiding stainless steel kitchenware entirely. Stainless steel pans with nickel in the alloy can introduce substantial amounts of nickel into food, ranging anywhere from 0 to 40 μg per 100g of food, depending on the properties of the pan and the food. They can release significantly more nickel into food when they are new, the amount settling down after about 5 uses. However, there are grades of stainless steel that only contain small amounts of nickel. Flatware composition is described by a system of two numbers, where the first is the percent chrome and the second is the percent nickel: 18/0, 18/8, and 18/10. The 18/0 stainless steel contains no nickel (intentionally). This system is also used for some pots and pans. In the SAE grading system, low nickel stainless steel grades that are used in kitchenware include 430, 436 and 440.
For pots and pans, aluminum, copper, coated, and cast iron have been recommended. However, studies have been contradictory. Pans labelled as "Aluminum" have tested well and badly. Cast iron and carbon steel have tested well, but even they can have up to 5% nickel added. Pans with a coating on them might still leach nickel. If the composition of a pan is not specified to be one of the low nickel options above, contact the manufacturer to find out if nickel is part of its formula.
Pyrex (clear glass) bakeware has been suggested in online communities as a safe option. Parchment paper and silicone liners are a great way to reuse your existing metal bakeware.
For cutlery, look for 18/0 stainless steel, or switch to plastic cutlery. Non-metal chopsticks are also a good option. Kitchen knives are made of a wider variety of alloys than cutlery, so you can contact the manufacturers to find out what they use. Ceramic kitchen knives, peelers and other tools are available. When food preparation tools are not being used on hot or acidic foods for much time, their nickel release should in theory be small.
Studies about the amount of nickel that comes from coffee makers and kettles have been contradictory. In one study kettles were found to release more nickel than coffee makers, and in another the opposite trend was found, with coffee makers releasing far more nickel than kettles (particularly espresso machines with a portafilter). Practically speaking, it’s difficult to know what metals a kettle or coffee maker contains. Non-metal alternatives include: boiling water in a Pyrex measuring cup in a microwave or a glass stove-top kettle; using an AeroPress or a ceramic pour-over coffee maker; and steeping tea in a Bodum Tea for One.
If you have no alternative to a metal-element kettle or coffee maker, use fresh water every time you use it. When you decalcify your coffee maker or kettle, run it through several times before drinking because the decalcification temporarily increases the amount of metal that leaches out.
Stainless steel mugs are not a good idea for those with SNAS. Acidic fruit juice in a stainless steel cup can add over 1000 micrograms to the drink in a day. While less so than juice, coffee and tea are still acidic. Since acidity, heat and time are a recipe for corrosion, using steel mugs with hot drinks has the potential to add a lot of nickel.
Medications and supplements all contain nickel in varying amounts. In the majority of cases nickel is not included intentionally, but is a contaminant that is picked up during the manufacturing process. The international agreement that sets the upper limit for nickel in pharmaceuticals, ICH Q3D, doesn't account for nickel allergy; it is concerned with nickel toxicity and limits oral nickel to 220 μg per daily dose. Few supplement manufacturers test their products for nickel content at all.
Do not stop taking any prescribed medications or supplements without medical supervision. If you suspect that you are reacting to a medication, talk to your doctor about alternative medications or having your medicine made at a compounding pharmacy without the worrisome fillers, and ask them to report an adverse event to the relevant authorities. (In Canada this is Health Canada and in the US it is the FDA.)
In pharmaceutical medications, the fillers (excipients) that have been found to have higher amounts of nickel in them include iron-based excipients (e.g. ferric oxide, ferrous oxide, carbonyl iron), dibasic calcium phosphate, ethylcellulose and talc. One paper shows a worst-case scenario for nickel in a hypothetical drug at 25 μg, however in studies of real pharmaceuticals, 84% to 100% were low, with less than 1 μg/g nickel.
Because there are so many brands and combinations of ingredients in vitamins and herbal products, it isn't possible to guess how much nickel is in a supplement. In what little science that exists, the only thing we can be sure of is that we can't be sure of them. While some brands of injectable B12 and vitamin E were found to have negligible levels of nickel per dose (less than 0.06 μg/g), oral iron supplements appear to be highly contaminated just like iron in pharmaceuticals. Various prenatal vitamins have been found to have anywhere from 0.08 to 34 μg of nickel, averaging 5 μg/day. In two studies of nickel in plant-based supplements, the nickel content ranged from undetectable to over 15 μg; in these studies 19% and 67% had less than 1 μg/g nickel.
Statistically, supplements have been shown to increase urinary nickel levels and most low nickel diets recommend stopping all supplements with the notable exception of vitamin C. When you decide to add a supplement, do it one at a time so that you can tell what effect it's having, positive or negative. Choose brands that have the least fillers in them to reduce the risk of increasing your nickel intake.
Vitamin C, also known as ascorbic acid, is recommended as part of a low nickel diet, taken with every meal so that it can mix with the food. It has been proven to interfere with the absorption of nickel into the bloodstream. It often comes in a 500 mg dose, which is still below the tolerable upper limit for teens and adults at 3 doses per day. For children’s dosages, consult your child’s doctor.
Look for a vitamin C supplement with the fewest filler ingredients. If ascorbic acid disagrees with you, consider a mineral ascorbate form such as calcium ascorbate or magnesium ascorbate. If you have tooth sensitivity, you might want to avoid powdered vitamin C. If you have a history of kidney stones, consult your doctor. Check with your doctor or pharmacist for potential interactions with medications, and be aware that high doses of vitamin C can interfere with urine dipstick tests.
Iron deficiency or an iron-deficient diet may result in increased uptake of nickel. The theory is that the molecule that transfers metals across the intestinal wall, divalent metal transporter (DMT), prefers iron over all other metals including nickel. If you're iron deficient, your body produces more DMT in its desperation to get more iron, and in so doing transfers more nickel and other metals into your bloodstream. It's important for this reason (among others) to get tested regularly for iron deficiency and take a supplement if one is prescribed by your doctor. It has also been recommended to simply eat a high iron diet.
Keep in mind that the RDA for iron for adolescents and adults is 18 mg/day, and the upper limit is 45 mg/day, from all sources combined. There is a risk of accidental overdose with iron supplements, so talk to your doctor first. Iron supplements can contain significant amounts of nickel themselves.
Probiotics have been shown to be beneficial for the healing of the gut and skin. L. reuteri DSM 17938, sold under the brand name Biogaia, was helpful in the treatment of SNAS, and a combination of L. reuteri DSM 122460 and L. rhamnosus 19070-2 improved atopic dermatitis in another study. In another study using a broader spectrum of probiotics tailored to the type of dysbiosis, the probiotics increased the rate of successfully fixing the dysbiosis from 41% to 73% compared to a low nickel diet alone.
Although not recommended in any low nickel diet research, vitamin A has been shown to be helpful in decreasing intestinal permeability (and thereby treating IBS), and in one study, vitamin A supplementation was shown to lower blood levels of nickel. However, vitamin A toxicity can cause liver damage, so care should be taken not to exceed the tolerable upper limit: for adults, the tolerable upper limit is 10000 IU/day of preformed vitamin A (retinol) from all sources. The beta-carotene found in most food is converted into vitamin A in the body only as needed; foods with preformed vitamin A include liver and other organ meats, cod liver oil, eggs, dairy, and some fortified cereals.
Nickel is ubiquitous, meaning it is found everywhere. It's important to understand that the term "nickel-free" has no legal or scientific definition despite its widespread use. A product marketed as "nickel-free" doesn't even have to be low nickel, let alone free of nickel. The widely-used terms "surgical stainless steel" and "medical grade stainless steel" have no formal definition and are used to describe any grade of stainless steel that is corrosion resistant in wet environments; it does not mean the product is hypoallergenic or even meets the standards that have been developed for surgical applications (e.g., ISO 5832−1 and ASTM F138−19). Even the products that follow these specifications can contain as much as 15% nickel. However, with skin contact the important thing isn't as much nickel content as it is how much nickel is released from the item. On skin, the amount of nickel released is influenced by many things, including: whether the site gets wet or sweaty; the quality of the sweat; the duration and frequency of exposure time; how new the metal is; and friction.
So, how much nickel release does it take to make an allergic person have a reaction to skin contact? This varies a lot, but the European Union settled on 0.5 μg/cm2/week (and lower for earring posts) in its 1993 Nickel Directive, legislation intended to reduce the rate of nickel sensitization. This has been shown to be roughly equivalent to 10 parts per million (ppm). Most people with ACD have a higher threshold, between 10 and 100 ppm. The most sensitive people can react to contact with even lower amounts of nickel, as low as 1 ppm, particularly if the skin barrier is damaged or at the site of previous dermatitis. It has been suggested that people with SNAS may be more sensitive than the rest of the nickel-allergic population.
When your allergy is systemic, even if you're not concerned with rashes or eczema you can still reduce your total nickel exposure by reducing skin contact. Although the actual amount of nickel that it contributes hasn't been determined, research has shown that nickel can penetrate your skin and reach your bloodstream. Consider these common exposure sources:
You can use a dimethylglyoxime (DMG) test to test the exposed metals around you. When this liquid is rubbed on a surface that releases more than 10 ppm nickel, it turns pink. The test isn't perfect, though. If the test is positive you can be 98% sure that it is releasing more than 10 ppm nickel. But if the test is negative it's not very reliable; there's a 40% chance that the test was wrong. Keep this in mind for metallic objects that are routinely in contact with your skin.
Stainless steels, while more corrosion resistant than other alloys, have been found to release nickel in amounts anywhere from 0.02 to 10 ug/cm2/week in sweaty conditions. While there is no direct relationship between the composition of a stainless steel and its release rate, grade "316L" has been shown to release less nickel under sweaty conditions. However, the composition of 316L stainless steel is only approximately defined. There are several varieties of stainless steel that may be labelled as 316L, and testing has shown that they corrode differently depending on the conditions, sometimes exceeding the EU limit.
To mitigate exposure risks, you can contact the manufacturer to ask about any product's chemical composition, cover up exposed metals, and join support groups to find suitably low nickel products. Consider buying your cosmetics and other personal care products from a retailer that lists the nickel content of products that have been tested, such as Ecco-Verde. Consider cotton glove liners if you have hand dermatitis.
Air pollution, dust, and pollen also contain nickel. Occupational exposures for dental workers and metal workers have been observed, sometimes in high amounts. How much these types of airborne nickel contribute to SNAS hasn't been established, but it's something to keep in mind.
Nickel is in tobacco, which is expected because it's a plant. Nickel is found in higher amounts in the blood and urine of smokers, meaning it's getting into your body through your lungs. More smokers are sensitized to nickel than non-smokers. In a case study, a woman had full remission of her widespread muscle pain within 2 months of quitting smoking and eliminating oatmeal, licorice and chocolate. Her symptoms returned when she began smoking again. If you're thinking you can replace it with e-cigarettes or vaping — nickel is found in even higher amounts in e-cigarettes.
Nickel is found in tattoo inks of all colours, not as a primary ingredient but as a contaminant. Inks containing titanium dioxide (bright colours) abrade the needles, leaving pieces of them embedded in the skin. Local reactions can appear years after the tattoo was done, sometimes triggered by other exposures like medical implants or the addition of more tattoos. It's unknown how much tattoos contribute to SNAS. A new tattoo is an unnecessary risk if it is not medically required. If you have a tattoo that you want to remove, be aware that laser removal may result in a systemic allergic reaction.
Nickel is a common element in dental alloys, and is always present in trace amounts, even when they are labelled "nickel-free". Likewise, "pure titanium" has been found to contain as much as 13 ppm nickel, and titanium alloys up to 31 ppm nickel. Although dental amalgam is not intended to contain nickel, it has been measured to contain 8 to 9 ppm. Even zirconia dental implants have been found to contain up to 11 ppm nickel.
Dental metals are a continuous oral source of nickel through galvanic corrosion, where the metals interact with each other through saliva that is constantly refreshing itself. The interaction is stronger when metals with different properties coexist, as can easily happen over a lifetime of dental repairs. There are cases where removal of the dental metals has resolved or improved SNAS symptoms.
To illustrate how much nickel can come from dental metals, consider a study that measured nickel in the saliva of patients with titanium-based implants. The implants contributed an extra 19 to 20 μg of nickel per litre of saliva, on average. In another study of fixed orthodontics the contribution was found to be less, averaging 6.6 μg/L. Using the lower estimate, along with other research that found a median salivary flow rate of 0.69 L/day (ranging widely from 0.14 to 2.88 L/day), the contribution to oral nickel could be as little as 1 μg/day or as much as 19 μg/day. The contribution can therefore be significant in some, but not all, cases.
One study concluded that the nickel exposure from Ni–Cr dental alloys might be at the same level as dietary intake or even higher. However, the same study found that things can change over time; in people with nickel-containing crowns, their average urinary nickel decreased to approximately the same level as the control group's after about 1 month. (This is interesting since stainless steel cookware and implants do the same thing.)
Discuss the risks and benefits of removal and replacement with your dental professionals. If it's too risky to remove your dental metals, there may still be some things you can do. If you can replace some of the restorations, it could reduce the chemical interactions; try to only keep metals with similar properties. Fluoride mouthwash causes more nickel to be released from metals. If you're getting something new, ask your dentist for the detailed composition of the materials they're recommending.
Medical implants are often made of metal for their strength, but there is increasing evidence of allergies to them. In 2019 the US Food and Drug Administration released a comprehensive review of metals used in biological environments. A fundamental challenge, they conclude, "is that the mechanisms underlying the biological responses to metal implants are not fully understood." Adverse reactions are complex, and corrosion in real-world biological environments needs research. Importantly, they note that allergies are not the only factor in implant failures and systemic symptoms. Their review of knee and hip replacement revisions shows that not everyone who is allergic to nickel reacts to the nickel in their implant, and replacement of the implant with a non-metal alternative doesn't always resolve the pain. So, if you have a metal implant it is important to keep in mind that every case is unique; even if you have a nickel allergy, it doesn’t necessarily mean that your implant is the root cause of your symptoms. But it's certainly something to discuss with your medical team.
While the results for knee and hip revisions are mixed, case studies abound of patients with a confirmed allergy whose symptoms completely resolved after removal of an allergenic medical device:
In some of the above cases the allergy was relatively obvious, showing itself as swelling, localized dermatitis, or loosening/failure. In other cases the dermatitis was widespread making it difficult to pinpoint the origin, or there was no dermatitis at all but the implant was persistently painful, or the symptoms were non-specific such as fatigue, widespread pain, or headaches.
Note: If you have any symptoms of nickel toxicity, do not hesitate to ask your doctor for a blood test to determine whether your blood contains elevated levels of nickel. If so, they may recommend medical procedures to reduce the accumulated nickel.
Corrosion in implants is different than on the skin or in dental applications, because the environment is different. Whereas sweat and saliva are relatively simple to simulate for testing, the internal environment is full of other compounds, such as blood, proteins, and inflammatory by-products. The traditional testing with saline or artificial sweat isn't good enough. Nickel release into blood plasma is approximately doubled as compared with release into artificial sweat. Inflammation leads to more aggressive corrosion due to the presence of peroxide, an acidic environment, and various salts. In one study, the nickel released in the initial 24 hours was over 300 times greater in an inflammatory solution compared to a saline solution. However, like all the other applications, nickel release decreases over time, becoming substantially lower after about a week. In addition, more nickel is released when the surface of the metal is roughed up, which is more of a consideration for implants where two surfaces rub against one another, such as screws or joints.
If you have an implant that you suspect, work with your medical team to come up with a plan that minimizes the risk to your health while addressing your concerns. In some cases the risks will outweigh the benefits, making it impractical, or even impossible, to take action on this front. If that's the case for you, a low nickel diet and external avoidance may be enough, in theory, to improve your symptoms by turning down the taps filling your nickel bucket (see the bucket analogy). There are also pharmaceutical approaches that may help.
If you and your medical team decide to replace an implant, consider following:
If you need a new implant and you want to test your reaction pre-implantation, ask your medical team about doing a real-life test with a sample of the implant. A sample could be taped to your arm for a period of time and the skin reaction assessed. However, this method is not necessarily an accurate prediction of whether an implant reaction will occur, and although invasive, it may be more predictive to implant the disc under the skin. Another approach to ask about is called an Oral Mucosa Patch Test (OMPT), where the inside of the lip is the test area.
If you have other contact allergies, they may also be contributing to your systemic symptoms. Examples of common contact allergens that are also found in food are cobalt, propylene glycol, propolis, linalool, balsam of Peru, compositae, and formaldehyde. Polysensitization, or having more than one allergy, is common with nickel allergy. Talk to your medical team about patch testing for these substances.
Other IgE-mediated food allergies also contribute to systemic symptoms. Even IgE-mediated pollen allergies can contribute; Oral Allergy Syndrome happens when the immune system confuses a protein in a fresh fruit or vegetable with a pollen protein of similar shape. This leads to burning and itching in mouth and throat, issues further down the digestive tract, and systemic symptoms such as asthma, hives, rhinoconjunctivitis and dermatitis. The offending proteins are usually broken down by heat, so many of these foods can still be enjoyed if cooked thoroughly. The test for IgE-mediated food and pollen allergies is called "prick testing" and can be obtained through your doctor.
Histamine is an important molecule that plays many roles in the body, including immune responses. Histamine intolerance is a condition in which there is chronically more histamine in the body than there should be, and the overlap with SNAS symptoms is substantial. Consult your health care team for testing to determine whether this is the case for you, in which case a low histamine diet or a diamine oxidase (DAO) enzyme supplement to be taken with meals may be appropriate.
Lactose intolerance is highly correlated with SNAS, with about 75% having both in one study. Non-celiac wheat sensitivity has been correlated with systemic nickel allergy to a small degree. Since wheat contains both gluten and fructans (a FODMAP, which can also cause IBS symptoms), it is hard to tell which one you’re actually reacting to when you cut out wheat-based products. In one study 70% of people who thought they were gluten-sensitive turned out to actually be sensitive to fructans. Talk to your health care team about ruling out celiac disease and lactose intolerance if you suspect them.
There is a bottomless pit of possible sensitivities, and to try to list them all would only lead to madness. Other common food sensitivities include nightshades, salicylates, and oxalates. Talk to your medical team for advice on how best to identify your allergies and sensitivities.
Some low nickel diets also restrict foods that aren’t typically high in nickel but are observed to elicit a reaction nonetheless. One study incorporated the restriction of vasoactive amines (such as histamine). Another study identified foods that triggered reactions in a significant number of SNAS patients, and not all of them are very high in nickel: tomato, lettuce, broccoli, cauliflower, onions, mushrooms, corn, cabbage and carrots; shrimp and seafood; and baked goods. In other studies gelatin was identified as a food that must be avoided despite food studies showing gelatin to be low nickel. Soybeans are a high nickel food so a reaction would be expected for serving-size amounts, but even traces of soy and additives derived from soy are enough to set off some people in the SNAS online community. Although the observed reactions could still be nickel because there is always a range of nickel content and sometimes it can be wide, all of these observations align with the food allergies and sensitivities above. Healing from the effects of a systemic nickel allergy is often about more than just nickel.
Although it's tempting to hurry along the process of getting all the accumulated nickel out of your body by taking "heavy metal detox" supplements, their use for this purpose isn't currently supported by science. The pharmaceuticals that are used to chelate other heavy metals do not chelate nickel, and they are hard on the body and only recommended for acute toxicity. Plant-based supplements haven't been tested for the chelation of nickel or the treatment of SNAS, they haven't been shown to be selective for nickel over minerals with nutritional value, and like all supplements, some of them will do you more harm than good through their own nickel content.
Nickel is excreted in sweat, urine and feces. If you think you've been exposed to more than just dietary nickel, please consult with your medical team to talk about the best way to eliminate the excess. Otherwise, supporting your body's own detoxification systems is enough to gradually get rid of it:
The nickel bucket analogy is a modification of existing allergy bucket analogies, designed to illustrate the concepts of nickel accumulation, elimination, and allergy in simple terms. Disclaimer: this is not intended to be medically accurate, it is only intended to help you visualize the concepts.
Imagine a bucket that has a small hole at the bottom. Water fills the bucket from a tap. If the water comes in at the same rate as the water leaves through the hole in the bottom, the bucket will never fill. If the water comes in faster than it can leave, the bucket will eventually overflow and make a mess.
In the "nickel bucket analogy", water represents nickel. The taps represent all of your possible exposure sources (diet, environment, and others). The hole at the bottom represents your body’s nickel elimination routes (your kidneys, liver and skin). The size of the bucket represents how much nickel you can tolerate before your nickel bucket overflows and you become a symptomatic mess.
If nickel comes in at the same rate as it can be eliminated, your nickel bucket will never overflow. This is the ultimate goal. But at the beginning, your bucket is overflowing. When you practice avoidance and reduce the nickel in your diet, you’re closing down the taps, which will eventually get the level in your bucket below the rim.
When your nickel level is near the rim of the bucket, it doesn’t take much to throw off the equilibrium of the incoming/outgoing nickel. This is always the case when you're starting out on a low nickel diet, but even after you've been at it for years the level can slowly rise without your realizing it, until it's near the rim again and seemingly without reason sloshes over, making your symptoms come back.
Of course, this analogy is an over-simplification of a very complex process. For instance, it doesn't account for the nickel that is stored in soft tissues and bone, which gets released into blood and then either eliminated or redistributed to other locations. This could add an element of unpredictability to your symptoms that should reduce as you slowly eliminate your stored nickel.
Research has shown that eliminating a high, but still normal, dietary dose of nickel takes just a few days. However, other research showed that the process is very different for toxic levels of nickel, where elimination happens in two phases: a fast phase and a slow phase. The fast phase lasts about 3 months, while the slow phase continues over years. The researchers think that this "fast phase" lasts longer than it does for dietary doses because at toxic levels our elimination routes are saturated, and the slow phase is likely related to a redistribution process. Most low nickel diet research predicts success in 1 to 3 months, but that will change depending on your past exposure level, how long you were exposed, how much you can limit your exposure, and how well your elimination routes are working. Some studies allowed for as long as 6 months for the diet to take effect.
There are two types of tests that can diagnose your nickel allergy: patch testing and blood testing. Patch testing, wherein a small patch of the allergen is placed on your skin for 24 hours and your reaction over the following days or weeks is monitored, is done by some, but not all, allergists and dermatologists. The American Contact Dermatitis Society can help you find a patch test provider. With the help of an allergist or dermatologist you can get patch tested for many contact allergens at once, which is important because all of your allergens contribute to your symptoms. Propylene glycol, propolis, linalool, and compositae are also found in foods and are not on the T.R.U.E. test, a standard test used in the United States. Consider asking for a larger panel. Be aware that a nickel patch test can be very delayed, appearing up to 10 days after patch removal.
Blood testing for metal allergies is available through MELISA and Orthopedic Analysis. A doctor must place the order. While patch testing is still considered the gold standard for diagnosing contact allergies, it does have its limitations. In cases where the patch test is negative or inconclusive but a nickel allergy is still suspected, blood testing can be used as a backup test to confirm the diagnosis. There are some circumstances in which a blood test is preferable to a patch test, and the blood test may be more relevant in patients sensitized to nickel by internal exposure, for example patients with metal implants and/or no history of skin reactions.
Other helpful SNAS-specific advice can be found at The Reluctant Health Nut.
The Facebook group Low Nickel Diet - Eating Well with Nickel Allergy/SNAS group is a good support system that provides resources and personal experiences from SNAS sufferers.
Vita Kristina provides a low nickel diet course and one-on-one coaching, including meal planning and nutrition.
The Excel workbook contains macros that generate Score Sheets based on location. The first sheet contains notes and information on how to use it. The "Main" sheet contains the data. The "Settings" sheet is where the desired location is defined with a latitude and longitude and some customizations can be set. The Score Sheets above were generated with Level 2 granularity, but you can generate a higher-level view by choosing Level 1. You can choose to ignore cooked and canned foods, but be aware this won't work for Level 1 granularity because cooked and canned are sometimes combined into a single food label.
The GenerateAnalysisSheet macro will generate two new sheets with the results for the current settings, one for all foods, and one for foods marked as "Favourites" in the last column of the "Main" sheet. These are not the printable sheets, but can be pasted into a word processing program for pretty formatting. If you want to auto-generate it as a pretty-printable sheet, you have to add your location to the "Weights" sheet, sort the list alphabetically by the Data Label column, and then add the row index of the location you want to the array rowArr in the GenerateAllSheets macro. Running GenerateAllSheets should create the printable Score Sheet.
If you need a custom location and you can’t work with Excel, or the sheets and macros look like spaghetti, send us a note. We're happy to help.