There are two schools of thought when it comes to mineral oil and cutting boards.
The first is mineral oil is a byproduct of the petroleum refining process. Then again, so is petroleum jelly. However, we don't typically expose our food to petroleum jelly either. So, there are those who believe that continuous exposure to mineral oil over time could produce adverse effects. There are no studies that have been performed to date to either confirm or deny this notion. Therefore, its still just a matter of speculation.
For me, I'm not comfortable with the thought of using a product that is part of the oil refining process on a surface that I use to prepare food. But, that's just me.
I use 3 parts coconut oil and 1 part beeswax and heat it so the two will combine. The beeswax gives just enough water protection to keep moisture from getting into the wood and the oil preserves the wood.
Coconut oil is a good choice because it does not go rancid like other oils such as olive oil etc. I have an oak cutting board that belonged to my mother that is approaching the 30 year mark. It has always been oiled with coconut oil and beeswax and is still going strong.
Depending on frequency of use, the board should be oiled anywhere from once a week to perhaps once every month or two.
Also, I would recommend two cutting boards. One for meat and fish and the other for vegetables and non meat items such as cheese. Natural wood has varying antibacterial properties. Oak is said to be the best in this regard. Try to avoid plastic cutting boards as they tend to become bacteria magnets, especially when they have cut marks.
Rinse the vegetable cutting board generously with warm water and dry with a towel.
The meat board, wash with hot water and a mild antibacterial soap or regular soap. If the board is properly oiled, the bacteria from the meat and fish will not penetrate the board and fester. Because you are using hot water on the meat board, you may need to oil the board a little more often.
Having said all that, its all still a matter of personal preference.
Incidentally, coconut oil is great for oiling cast iron cookware.