How is Nutrition Determined?
To scientifically determine the nutritional values of any food, a sample must be sent to a certified lab that runs various highly calibrated tests to determine what the nutritional make up is of that food. These tests have specific methods on how the samples are prepared and how the tests are run to ensure that the values they return are accurate. These tests are repeated over and over again until enough data has been collected to estimate the ranges that the food will have, and then a nutritional fact table (NFT) is created based on the worst-case values of that data set.
Samples from the same variety, and even from the same field, planted at the same time, can be shown to have different nutritional values when tested. This is because the potato pulls nutrients from the soil and different parts of the same field may have more soil nutrients, water, and sun during the development of that tuber. This is why it is important when trying to determine the nutritional value that multiple samples from multiple regions are collected and analyzed so that you can see the ranges that a single variety will have.
Most potato packaging displaying a Nutrition Facts Table (NFT) is using the generic potato table that have been approved by the USDA. It is displayed on the right side of this page.
Depending on the variety, where/when it was grown and the size of potato can all affect the levels of nutrients within that specific potato.
A Potatoes Color, What Does it Mean For Nutrients?
There are thousands of potato varieties, each of them with unique nutritional properties. In general, you will be able to tell if a particular variety is higher in a certain nutritional property than another by its color. Here is how color translates to nutrition:
Blue or Purple skin and/or flesh are an indication that this variety will have higher anthocyanins than other potatoes. Anthocyanins are class of nutrients that belong to a nutrition group called flavonoids and are powerful antioxidants.
Red color is associated with Lycopene. Lycopene is a carotenoid (class of antioxidant) that is red in color. Lycopene is said to be the most powerful of all the carotenoids.
White color is associated with Allicin, an organic compound that exhibits antibacterial and anti-fungal properties. Allicin has the ability to dissolve fats. It is slowly destroyed by storage and quickly destroyed by cooking.
Yellow or Orange are associated with Beta Carotene, a class of molecules in the carotene group, it is also known as Vitamin A.
Glycemic Index and Potatoes
Potatoes get a bad rap when it comes to the glycemic index. The average potato is considered as having a “high” glycemic index, but just as in the case of nutritional value, not all potatoes fall into this category. Some potato varieties have actually been tested and given a “low” glycemic index.