Can coffee consumption affect inflammation and lower risk of CVD, mortality?

A systematic review of randomized controlled trials (RCTs) has found no conclusive evidence that the anti-inflammatory effect of coffee plays a major role in the reduction of all-cause death noted in observational studies.

“Coffee is one of the most widely consumed beverages globally,” the investigators said. “A substantial number of observational data suggest an inverse relationship between coffee consumption and the risk for cardiovascular disease.”

This review specifically assessed the impact of coffee on inflammatory biomarkers as a potential mechanistic basis for the above observation. Bibliographic databases were systematically reviewed, including PubMed (NCBI), Embase (Elsevier), Cinahl (EBSCO), Web of Science (Clarivate Analytics), Cochrane Central Register of Controlled Trials (EBSCO), and CAB Abstracts (Clarivate Analytics).

The investigators looked for RCTs that examined the effect of drinking coffee on inflammatory markers of cardiovascular risk.

A total of 1,631 studies were identified from the electronic databases. Forty full-text documents were examined after removing duplicate records and ineligible studies, of which 17 were found to be eligible for further analysis.

Based on the results, boiled coffee appeared to increase total and low-density lipoprotein cholesterol and apolipoprotein B. However, no similar effect was observed for filtered coffee. Most notably, one study demonstrated a marked elevation in levels of blood interleukin 6 among individuals who consumed caffeinated coffee as opposed to those who did not drink coffee.

“The body of evidence relating coffee consumption to specific candidate biomarkers is weak and limited to small studies of brief duration,” the investigators said. “Information on well-known biomarkers, including tumour necrosis factor-alpha, leptin, homocysteine, and fibrinogen, is mostly absent.

Apart from caffeine, coffee contains bioactive substances, such as diterpenes, polyphenols, and melanoidins.