I deal with a lot of food professionals, and I use products that I don't need to wonder or worry about. If it has merit in the food industry, in inspected facilities, I will defer to their guidelines. Mineral oil and bees wax are recognized and accepted, food safe. I'm sure flax and coconut oils are fine to use. They provide very nice finishes. For a cutting board, the pores of the wood open and close with a self healing effect on end grain boards. A finish that "cures" or hardens will show those scratches, and I have heard of them flaking, and yellowing.
I highly recommend this.
http://theboardsmith.com/product/board-butter/