Olive oil has been in use for thousands of years, no problem whatsoever. But it is the most expensive.
Discussion
Very few olive oils are pure olive oils. Most of them are spiked with soybean oil (the worst one), at least in the US.
That being said, the ratio of saturated:unsaturated fats seems to be the most important.
That's sad to hear. In Spain we produce and sell **virgin** cold extracted olive oil. And our diet is based on that. That's probably the reason we have the second most life expectancy in the world (only after Japan). Because we use good oils and good vegetables and legumes as base diets.