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:

1H NMR-based metabolic fingerprinting of urine metabolites after consumption of lingonberries (Vaccinium vitis-idaea) with a high-fat meal. The use of NMR metabolomics in clinical trials is growing; however, reports of postprandial experiments in humans are scarce. The present study investigated whether consumption of lingonberries as a supplement to an oil-rich meal modifies the postprandial fingerprints of human urine. Urine samples were analysed by (1)H NMR, and untargeted multivariate analysis was applied to the data for comprehensive fingerprinting. A clear separation of postprandial lingonberry meal samples was revealed. To evaluate statistical differences, a targeted approach was applied for the informative spectral areas. Significantly (p<0.05) increased levels of polyphenol metabolites, hippuric acid and 4-hydroxyhippuric acid, and decreased creatinine and dimethylamine levels were the major explanations for the grouping of the postprandial samples after the different meals. Thus, inclusion of polyphenol-rich lingonberry powder in a rapeseed oil-rich meal modifies the metabolic profile of urine which may be used to reveal both consumption of berries and health-promoting changes in the common metabolism.
{"Chemical": ["4-hydroxyhippuric acid", "dimethylamine", "creatinine", "polyphenol", "hippuric acid", "(1)H", "1H"]}