Hey Akari:
I don’t know about olive or vegetable oils, maybe someone else will have some info for you.
I use coco oil for hairballs and because it has other benefits too. My older cat (not the hyperthyroid kitty) had a terrible hairball issue. It was my fault though because I did not brush him enough. He coughed one up that was the size of a mouse one day. From that day forward I give him daily brushings and coco oil 2x/wk. Most of the time the brushing is only a couple of minutes, but brushing has made the most difference.
I also supplement all my cats with fish oil; it can help with hairballs too. Since they still get some fish in their diet, I don’t supplement anymore than once a week. I use CVS 1000 mg capsules. It’s purified to remove mercury and made without dairy or soy products. The EPA & DHA percentages are the same as other pet products for example Dr.’s Foster and Smith Premium Plus® Omega-3 Gel Caps. I poke a hole in the capsule and squeeze the oil over their food.
I used this PDF from Tuft’s Vet school for dosage amount/lbs, ingredient %, and brand information. The information in it pertains to heart disease so I do not follow the daily dosage instructions. I researched how often and how much to dose the cats from other sources.
http://www.google.com/url?url=http://vet.tufts.edu/heartsmart/resources/omega-3_supplementation.pdf&rct=j&frm=1&q=&esrc=s&sa=U&ei=apyOU7TcBNSxsQSvsIA4&ved=0CBcQFjAA&sig2=0_LYv32HiEiInKcfDfNOvQ&usg=AFQjCNHTgzeaTJ04dtmqZQ9Uenp1rqGVCQ
Here’s some information on hairballs:
http://healthypets.mercola.com/sites/healthypets/archive/2013/01/16/chronic-hairball.aspx
