Many of us take multiple medications.
That in itself is not a bad thing. All of your medications should be monitored by your physician including any supplements.
As for your other question, the causes for high levels of blood cholesterol are many and eating too much fat is the probably the most common cause. Genetics do play an important role too.
This is a pretty good explanation, I think.
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http://en.wikipedia.org/wiki/High_cholesterol