11307
Over 50 years ago , chromium ( Cr ) was proposed to be an essential trace element ; however , recent studies indicate that this status should be removed as the effects of Cr supplementation appear to be pharmacological rather than nutritional .
 chromium, Cr, Cr
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 chromium, Cr, Cr