I've been fairly comfortable using the USDA database, via
http://www.nutritiondata.com, to find values for the important nutrients (potassium, phosphorus, sodium, protein, etc.) in what I eat. Unfortunately, there are always food items that aren't listed, or are specific to a single brand and don't have complete information. I wonder if there is a better way to estimate the important values for these types of foods.
Mostly, I'm thinking about things that aren't common in the US, like ethnic foods. Even worse, a lot of the time these imported items don't even have the basic nutritional information in English on the package. For example, I have no idea how much potassium and phosphorus are in the Korean ingredient called doenjang.
Also, I've been munching on gummi bears and other gummi candies, and I can't find any information about the phosphorus content of gummies. I'm kind of thinking that they don't have an insignificant amount of phosphorus, as phosphorus is found in protein often, and gummies are made out of gelatin, a much higher concentration than Jello.
Anyway, just kinda voicing my frustrations on imperfect knowledge.