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:

Systematic literature review of the effects of food and drink advertising on food and drink-related behaviour, attitudes and beliefs in adult populations. A large body of research confirms that food advertising affects the food preferences and behaviour of children. The impact of food advertising on adults is less clear. We conducted a systematic review exploring the effects of advertising of food and non-alcoholic drinks (referred to as 'food' throughout) on food-related behaviour, attitudes and beliefs in adult populations. We searched seven electronic databases, grey literature sources, and references and citations of included material for experimental studies written in English investigating the effects of commercial food advertising on the food-related behaviours, attitudes and beliefs of adults aged 16 years and over. Nine studies, rated moderate to poor quality, were included in the review; all were from developed countries and explored the impact of televised food advertising. Overall, the results did not show conclusively whether or not food advertising affects food-related behaviour, attitudes or beliefs in adults, but suggest that the impact varies inconsistently within subgroups, including gender, weight and existing food psychology. The identification of a small number of relevant studies, none of which were high quality, and with substantial heterogeneity, highlights the need for further research. Future studies investigating longer term outcomes, diverse advertising formats, and in countries with different levels of economic development will be of particular value.
{"Chemical": []}