Nickel Navigator

Nickel Navigator is a support tool for individuals on a low-nickel diet. It presents nickel data for over 800 foods from hundreds of national food studies and scientific articles, while taking serving size into consideration. Explore the food groups to see which foods are the highest and lowest in nickel, or search for a food. Drill down into the data to understand how a food's nickel content varies, and the reliability of the statistics for that food. Estimate your daily nickel intake using the food journal. For more information, please see our new and improved User Guide inside the app, and below.

Disclaimer: This app is not intended to replace the advice of a medical professional. See a medical professional first for allergy testing, personalized advice, and to rule out other causes of your symptoms. If you need support beyond what the nickel data can provide, please reach out to a medical professional. Rebelytics does not provide medical advice.

No Internet connection is required. This app is free and is available as-is and in English only.

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Nickel Navigator User Guide (Android)

If you have been directed by a medical professional to follow a low nickel diet, Nickel Navigator can help you to decide what to eat. The app provides two tools: a food Explorer, and a food Journal. Through the Explorer you can view an international database of nickel in food, collected from government food studies and research papers, while taking serving size into consideration. The Journal allows you to estimate your daily nickel intake from the food amounts you record.

Note. This app is not intended to replace the advice of a medical professional. See a medical professional first for allergy testing, personalized advice and to rule out other causes of your symptoms.

This document describes what can be done ("How do I…?") by each of the entries in the Android Nickel Navigator menu along with some answers to frequently asked questions ("Please explain…"). Although written for the Android app, most of this document applies to both iOS and Android versions because their overall functionality is the same. For navigation items specific to the iOS version, please see the User Guide embedded within that app.

1. Journal

2. Serving Sizes

3. Explorer

4. Settings

5. User Guide

6. References

7. Important Notes

1 Journal

The Journal lets you track your dietary nickel intake by recording food choices in a log. The log is made up of pages, each of which contain food entries and/or notes. The amount of food in each entry is used to calculate the total nickel content of the page. A limit of 150 μg/day of dietary nickel is recommended, but individual needs will vary.

1.1 How Do I…?

Add, Edit, or Remove Pages in the Log
  • To add a new page to the log, touch the "+" button at the bottom right of the Journal screen. You will be prompted to enter a page title; touch "OKAY" when done.
  • To edit the title of an existing log page, long press the entry on the Journal screen. You will be prompted to enter the page title with the existing title pre-filled. When you are finished editing, confirm the changes by touching "OKAY".
  • To remove an existing log page, long press the entry on the Journal screen. You will be prompted to edit the title; touch "REMOVE" to delete the page (confirm with "YES").

View the Entries on a Log Page

The details of a log page can be viewed by touching the new entry title on the Journal screen.

Add a New Food Entry to a Log Page

Once you are viewing the entries on a log page, you can add a new food by doing the following:

  • Press the grocery cart button at the bottom right of the screen.
  • Type a few letters of the food name, you will be presented with a list of matching foods in the Nickel Navigator database.
  • You must select a food from this list.
  • You will be prompted to enter in the amount of food. This field is automatically filled in with the default serving size for that food. You can leave it as the default amount, or input a different value.
  • Touch "OK" to add the food.
  • The total amount of nickel is then updated at the top of the log.

Edit or Remove a Food Entry from a Log Page

You can touch the entry for a food to edit or remove the item.

Add a Note Entry to a Log Page

Add a note to the entry by touching the icon at the top right of the page. Enter text and touch "OK" when done.

Edit or Remove a Note Entry from a Log Page

Touching the note entry again opens the editor; changes can be made to the note and confirmed by touching "OK" when you are done. To remove the note, touch "REMOVE ITEM".

Print the Log

You can print the entire Journal by selecting the printer icon at the top right of the main Journal screen. This creates a tabular view of your log entries that you can print using your device's print services.

Change the Default Serving Size of a Food

See the Settings page.

Change the Default Units from Grams to Ounces

See the Settings page.

1.2 Please Explain…

What Log Pages are Used for

A log page can be used any time you want to calculate the amount of nickel in a list of foods, for example:

  • to track yor daily nickel intake;
  • to compute the nickel content of a recipe;
  • to design a menu for a special event.

What Note Entries are Used for

Notes can be a useful tool in a number of situations:

  • to keep track of symptoms, since systemic nickel allergy reactions usually take 1 to 3 days to appear;
  • to record a food choice if it is not in the Rebelytics database of nickel in foods (data does get added through updates).

2 Serving Sizes

The Serving Sizes page allows you to change the default food amounts to fit the way you eat; this makes it easier to enter foods in the Journal and helps when viewing foods in the Explorer. All the food classes available in Nickel Navigator are shown in a list along with their serving sizes in grams or ounces (see Settings to switch between the two). You can scroll through the list or search by keyword. Once the food class you are looking for is found, you can edit its default serving size.

2.1 How Do I…?

Search for a Food Class

To filter the list of food classes, enter a keyword in the search bar at the top of the list.

Change the Default Serving Size of a Food Class

To edit a food class, touch the entry on the Serving Sizes page. You will be prompted to enter the new amount in either grams or ounces (see Settings); confirm your choice by touching "OKAY".

Change the Default Units

See Settings.

Reset the Serving Sizes to their Original Values

See Settings.

2.2 Please Explain…

What is the Serving Size of a Food Class

Research papers report the nickel level of foods in micrograms (μg) per gram of food. However, it is easier to measure how much food we eat by the way it is served, e.g. a slice of pizza, or a glass of milk. The number of grams in a slice, glass, etc. is called a "serving size". A food class is a group of similar foods with similar serving sizes.

In the beginning, it's a good idea to measure how much food you're eating, so you can get a good estimate your preferred serving size. The blog 100 Grams gives a visual guide to what 100 grams of many different foods looks like, but we do recommend investing in a scale of your own. With practice, it becomes easy to estimate a serving size.

How the Default Serving Sizes are Chosen

Nickel Navigator displays the nickel content for a serving of a food using the serving sizes and food classes defined by Health Canada by default.

3 Explorer

The Explorer page lets you view what data is available in Nickel Navigator. The Explorer page starts as a list of food categories that can be expanded. You can browse the categories to view lists of foods and their average nickel content or search for the details page of a specific food. The details page for a particular food shows all its nickel measurements as both a graph and a data table.

3.1 How Do I…?

Browse the List of Food Groups

To expand and collapse a category of foods, touch the group label and scroll through the list.

Search for a Specific Food

From the main Explorer screen, the list can be filtered for a specific food by typing in keywords in the search bar.

View the Details Page for a Food

To view the details page for a specific food, touch its list entry on the main Explorer screen.

View References on a Food Details Page

To see which study a particular nickel value came from on a food details page, touch the list item. The reference will appear in a notification at the bottom of your screen.

3.2 Please Explain…

The Pizza Slice Icons in the Food List Entries

When viewing the Explorer main screen, each of the foods listed in a group will have a pizza slice icon beside its name. The icon is coloured using a stop light system, reflecting the amount of nickel it contains on average, in a serving of the food:

  • green — less than 10 μg;
  • yellow — less than 20 μg; and
  • red — more than 20 μg.

The Warnings that Appear on the Food List Entries

To make good decisions, it can be helpful to explore the data for a food to see how much data there is, how big the range is, and where the data comes from (see How to Read the Graph for more). Since this would be a lot of work to do for everything you eat, Nickel Navigator puts warnings under the names of foods that require more of your attention.

Any warnings about a food's nickel data are listed on the Explorer main screen under its name:

"Unreliable, (few) measurements"
Not all foods have enough measurements to get a reliable average value. In such a case, this message is given, including the number of measurements available, to let you know that the average value is questionable.
"(Very) wide variation"
Even when there is plenty of data, there are many things that can affect a measurement of nickel in a food, so it's important to recognize that there is always a range. The food that you're about to eat could fall anywhere within that range. If that range is (very) large, this warning is written under the food name.
"(Very) wide variation, possibly high nickel"
This warning is given when the average value per serving is low but some of the data is notably high in nickel.
How to Read the Graph on a Food Details Page

The food details page will display a list of all the data sources and where they were obtained, and a histogram of the data for a visual details. In a histogram, the entire range of values is divided into "bins" and each value is tossed into its corresponding bin. This gives you a count of the number of values in the data that fall within a certain range. The minimum and maximum values are marked at the left and right ends of the horizontal axis, respectively. In this graph, a tick is also drawn at the value's position on the horizontal axis, so you can see how the values form clusters within the range.

Colours on the graph and in the list of individual samples under it also follow the stop light system (see Pizza Slices), to show you whether the measurement is low, moderate, or high nickel. When the location bias feature is enabled (see Settings), the intensity of the colour is related to how far away you live from where the sample was taken. This means that samples that are close to you are bright and become more and more grey as they go farther away from your location.

A quick glance at the graph can give you a rough idea of what you can expect from your food. For example, you may want to know how likely it is that a food with a low average will have a high outlier. If the majority of the values fall into the lowest bins and there are few values in higher bins, you can reasonably expect that your food will also be low in nickel. Or, you may want to know how much faith you can put into the average value, and you can see this easily when there are only a few boxes on the histogram, and their colour will tell you whether the measurements were taken close to your geographical area. If there's a wide spread of values in all of the bins, and in all three colours, then a food naturally has a lot of variation and you should be cautious.

4 Settings

The Settings page collects options to customize Nickel Navigator. You can scroll through the list of options and modify them as you need.

4.1 How Do I…?

Change the Units to Ounces

Check the box labelled "Use ounces instead of grams" to use ounces as the default unit of weight (1 ounce is about 28.35 g). Doing this will automatically convert any food entries already recorded in the log (see Journal).

To go back to using grams, remove the check from the option box.

Enable/Disable Location Bias

The location bias is enabled ("ON") or disabled ("OFF") by touching the ON/OFF button. If you want this feature to use your device location services, ensure that they are turned on; for newer devices, you also have to enable location services specifically for Nickel Navigator in your device settings.

When location services aren't available, you can set your location manually in one of two ways:

  1. From a pull-down list of locations; this will set the latitude and longitude for you.
  2. Entering the latitude and longitude of your choosing (in degrees) in the number fields.

Clear the Food Favourite List

To clear the food favourites list, touch this settings label. Touch "OKAY" when asked for confirmation of your choice.

Reset Serving Sizes to their Original Defaults

To remove all custom serving sizes you have entered (see Serving Sizes), touch this settings label. Touch "OKAY" when asked for confirmation of your choice. This will restore all servings sizes to the values defined by Health Canada in 2022.

Save My Data

Touch this settings label to back up your current Nickel Navigator data.

Import My Data

Touch this settings label to read in the last saved Nickel Navigator data.

4.2 Please Explain…

What Location Bias Does

Since the amount of nickel found in a food can vary with where it was grown or produced, you have the option to use your location to bias the average, so that samples that were produced close to you are given more emphasis than those farther away.

What Resetting the Favourite Foods List Does

Once you have selected a food, it is added to an internal list of your favourite foods so that the next time you want to add it to your journal, it will appear at the top of the list of matching foods in the database. If your eating habits change, you might want to reset this list.

What Data Can be Saved and Imported

Use this feature if you want to do some temporary fiddling without worrying about losing your data. The following content is preserved by saving:

  • All pages, food entries, and notes of the log (see Journal)
  • All custom serving sizes (see Serving Sizes)
  • The setting and coordinates of the location bias

5 User Guide

The User Guide page contains this document.

6 References

The References page contains a full bibliography of all the data sources used in Nickel Navigator. The list can be searched by author and title. Touching a reference copies it to the clipboard for use with other applications.

7 Important Notes

This can only give an estimate

Understand that the daily nickel tally is only an approximation of the actual amount of nickel you have consumed. It uses average values, and many foods do not have enough samples for proper statistics, but it's probably good enough for a "ballpark" estimate.

Other nickel exposure routes

Be sure to check your cookware and utensils for nickel content, and other food-borne exposures such as metal water bottles and mugs. See our Low Nickel Diet page for more information on cooking, and other ways you can reduce your total nickel exposure.

Cooked vs. raw categories

You may be wondering why cooked meats and vegetables are separated from their raw counterparts, along with "composite" foods, which are a mixture of raw and cooked that are also placed in the cooked category. This is because how a food is cooked can have a significant effect on its nickel content. It may take up nickel from the cookware, as in the case of pan-fried, or release its nickel into the cooking medium, as in the case of boiled. The result is a much wider variation in nickel content and a whole lot of doubt, because not only do we not always know how the food was prepared, but we don't often know what the equipment it was prepared with was made of. But it still serves an important purpose, and that is if you're eating out and can't control how a food is cooked, you can use the cooked values to estimate how much risk is introduced by these unknown factors. Some foods are affected more by cooking than others. Be sure to drill down into the data to see how much information you can get about cooking methods.

Learning More, Contributing, and Disclaimer

See our Nickel In Foods page for more discussion of the nickel data, and trends we observed by category.

If you have a data source (a new set of measurements or a journal article), please bring it to our attention at Rebelytics.

Rebelytics is not responsible for errors in the published data, and although every attempt has been made to transcribe the data accurately, we cannot guarantee 100% accuracy.