In a recent study, people who consumed excess coffee each morning tended to have higher blood levels of certain inflammatory proteins, compared to people who drank less coffee or who were non-coffee drinkers. Anything over a small cup (about 6.5 ounces) per day was associated with the increase in inflammatory markers.
High blood levels of certain inflammatory proteins have been linked to an increased risk of heart disease. Early research indicates that too much coffee each day may raise blood levels of inflammatory markers, such as interleukin-6, C-reactive protein, serum amyloid, and tumor necrosis factor alpha, but more research is needed to confirm the link. If you are concerned about your health and would like to cut back on coffee, try switching to tea for a couple days each week. If you need a caffeine fix in the morning, black teas will have more caffeine than green or herbal teas. Other good ways to protect your heart include eating a healthful diet that contains adequate fiber, fruits, vegetables, and unsaturated fats; limiting your intake of saturated fats and cholesterol; getting regular exercise; and taking measures to reduce stress.
Ref:
Associations between coffee consumption and inflammatory markers in healthy persons: the ATTICA study. Zampelas, A., Panagiotakos, D. B., Pitsavos, C., Chrysohoou, C., Stefanadis, C., The American Journal of Clinical Nutrition 2004 Oct;80(4):862-7.