There is not one straight answer. You need to work with a doctor to discover why it is high, which may be caused by medical conditions.
That being said, diet may help bring it down. Eating a diet rich in plant foods and low in saturated fats is key. Also, adding fatty fish twice a week (or fish oil if you don't eta fish) and healthy fats like nuts, avocado and olive oil can help as well. Lowering your intake of sugar nd refined carbohydrates is also part of an anti-inflammation diet.
This article outlines important diet changes you can make to lower your CRP, which is a marker for inflammation.
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