It seems to me one of the greatest sources of error in the data base are the % of the title nutrients. When scanning the bar code of a food I've found examples of mg of calcium and iron reported on the packing being directly numerically converted into %. E.g., A food can show 97.5 mg of calcium and 2.6 mg of iron per serving on the packaging, but when scanned and ported over into MFP it literally becomes 97.5% of calcium and 2.6% of iron. The food is then flagged as a high source of calcium within the app. However, the RDA for men aged 19 - 70 by the NIH (N=USA) is 1000 mg of calcium. So, in fact, this food is only 9.8% of the RDA for men aged 19-70 and women aged 19 - 50, and less at 8.1% for women aged 51 - 70 (RDA for women in this age group is 1200 mg of calcium). The error in the iron is worse. At 2.6 mg of iron per serving, this amounts to fully 32.5% of the RDA for men aged 19+, but significantly less for women aged 19-50 at 14.4%. In fact the food, while a decent source of Ca, is an excellent source of Fe (ignoring the bioavailability).
Why use %'s at all? Why not just use mg or micrograms as required? What does it mean in MFP when it tells me the % RDA of a nutrient? Has it taken my age and gender into account? When I "report a food" and come to add in the correct % for nutrients, what age and gender do I use?