I did manage to reduce mine by sticking to the government guidelines for fat intake (one third of calories)- although I could not get enough calories in per day doing that, so probably not sticking to the guidelines at all
There is a diet that includes plenty oats, soya, and almonds that is supposed to help but I have forgotten the name of it.
Plenty oats, pulses and nuts and adjusting your fat intake so that more comes from oily fish and seeds, rather than dairy and animal (don't cut them altogether) is probably a good compromise. Try to get plenty omega 3.
All the old research pointed to regular exercise and active lifestyle and this still holds true.