The database is composed of 954 food items (i.e. the same items present in the food nutrient composition file). First two columns report identifiers (as defined in the BEDCA database; see http://www.bedca.net/) and names of food items. The following columns summarize carbon, nitrogen (calculated using chemical formulas and referring to amino acid concentrations; i.e. nitrogen from proteins), phosphorus and nitrogen (last two columns) contents. In particular, in the last two columns the nitrogen content was estimated using conversion factors (i.e. the constant conversion factor that requires dividing the protein content by 6.25 - see Jones 1931, "Factors for converting percentages of nitrogen in foods and feeds into percentages of proteins", Circular No. 183, United States Department of Agriculture; and the conversion factors specific for food categories proposed by Mariotti et al. 2008, "Converting nitrogen into protein - beyond 6.25 and Jones' factors", Critical Reviews in Food Science and Nutrition 48, 177-184). All concentrations were expressed as grams per 100 grams of edible portion, fresh weight.