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:

The nutrient composition of three cuts obtained from P-class South African pork carcasses. The shoulder, loin and leg from P-class pork carcasses were used to determine the nutrient composition of both raw and cooked cuts. Significantly lower fat content were observed in the current study for the leg (5.21g/100g) and loin (6.99g/100g) compared to the shoulder cut (10.32g/100g). The overall percentage fat for all three cuts was less than 10% which is recommended by the South African Heart Mark. The cooked loin cut contained the most protein (27.50g/100g) of the three cooked cuts. When compared to other meat products (beef, mutton and chicken) it is clear that pork is a good source of B vitamins, especially vitamin B3. The cooked loin cut contained the least vitamin B1 (0.22mg/100g), B2 (0.02mg/100g) but the most vitamin B3 (7.09mg/100g), of the three cooked cuts. The 100g cooked shoulder, loin and leg cuts provide on average 40.11% protein, 5.19% magnesium, 3.37% calcium, 24.29% phosphorus, 18.22% zinc, 22.33% iron and 22.50% vitamin B1, 2.57% vitamin B2 and 42.6% vitamin B3 of Recommended Daily Allowances for males, age 25-50. Energy from a 100g portion provides 5.81% of the Recommended Daily Allowances. To conclude, the pork cuts are undoubtedly a good source of nutrients that is required for good health because it is high in protein, have a low fat content and are a nutrient-packed choice for the family and compares favourably with the fat, energy, and cholesterol content of many other meats and poultry.
{"Chemical": ["zinc", "phosphorus", "calcium", "vitamin B3", "iron", "cholesterol", "magnesium", "vitamin B2", "vitamin B1", "B vitamins"]}