As Sanguine rightly says, the Cholesterol figure on its own doesn't convey the whole picture. What you really need is the break down of the total Cholesterol figure ie the LDH and HDL components and the important thing is keeping the HDL levels as high as possible as the LDL component is undesirable.
It is sometimes better to measure the ratio of the HDL against the LDL rather than simply quoting the Total Cholesterol levels.
Incidentally diet alone is not generally responsible for any increases in Cholesterol, so eating foods that contain Cholesterol ie: shellfish will not increase your Cholesterol. There are medications available that can help to reduce Cholesterol within the body, but there is much controversy as to whether they are truly effective, with many having side effects in the process of taking them.
Personally I've been on Simvastatin for many years without problem, but from articles and surveys done here on this site it would seem that I'm in the minority.
