You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

FAO/INFOODS food composition database for biodiversity. Nutrient content can vary as much between different varieties of the same foods, as they do among different foods. Knowledge of varietal differences can therefore mean the difference between nutrient adequacy and inadequacy. The FAO/INFOODS food composition database for biodiversity has been developed with analytical data for foods described at the level of variety, cultivar and breed, and for underutilized and wild foods. It contains 6411 food entries and values for 451 components together with the bibliographic references and other information. The database is in MS Excel format and can be downloaded free-of-charge from the INFOODS website http://www.fao.org/infoods/biodiversity/index_en.stm. It is intended to annually publish new editions, making these data available for national and regional food composition databases. This database could be used to raise the awareness, promote and investigate food biodiversity and help to better estimate nutrient intakes.
{"Chemical": []}