C-reactive protein (CRP) is a substance found in blood that is a marker for inflammation in the body. High levels of this protein are associated with an increased risk of heart disease and low levels with a low risk. The notion that inflammation plays a central role in heart disease is relatively new, although we’ve long known that CRP levels go up to signal any type of inflammation. So far, no one knows exactly what contributes to the inflammation that might trigger or worsen heart disease.
However, the link between elevated CRP levels and heart disease has been demonstrated repeatedly, and there is some evidence that CRP may be a more important indicator of heart disease risk than high LDL ("bad") cholesterol. In an eight-year study involving 27,939 women led by Paul Ridker, MD, director of the Center for Cardiovascular Disease Prevention at Brigham and Women’s Hospital in Boston, more than half of the women who eventually developed heart disease had high CRP levels even though their LDL levels were not considered high. Dr. Ridker has estimated that the same may be true for 25 percent of the U.S. population. The study results were published in the November 14, 2002, issue of the New England Journal of Medicine. More recently, a Cleveland Clinic study found ultrasound evidence that clogged coronary arteries had not gotten worse among 502 patients who were most successful at lowering their CRP levels. The study was published in the Jan. 6, 2005, issue of the New England Journal of Medicine. The same issue carried results of another study by Dr. Ridker, which showed that lowering CRP levels with statin drugs reduced the risk of a second cardiac event.
The American Heart Association now recommends CRP testing when doctors aren’t sure how to treat patients with an intermediate risk, such as a 10-20 percent risk of having a heart attack in the next 10 years. (Other physicians, including Dr. Ridker, think that all adults should have a CRP test whenever their cholesterol is tested. I agree.) You should note that there are two tests for CRP – one is the acute-phase reactant that is elevated with general inflammatory changes in the body; the other test is hs-CRP – highly sensitive CRP – which is a measure of inflammation in blood vessels. This latter type is the test you should be getting.
To help lower CRP levels I recommend an anti-inflammatory diet, plus fish oil supplements if you are not eating two to three servings of fish – including oily species such as salmon or sardines – per week. You also could take anti-inflammatory herbs including ginger and turmeric. In addition, follow your doctor’s recommendations for heart health – quit smoking, watch your diet (particularly avoid saturated fats), and get regular exercise. A recent study at Johns Hopkins showed that as fitness levels go down, CRP levels go up. Researchers weren’t sure if poor fitness leads to an increase in CRP or vice versa, but exercise is an important part of maintaining heart health in any case.
Andrew Weil, M.D.