Coffee intake may have a variable effect on inflammation markers, with different responses noted between men and women and across various geographical regions.
The researchers carried out a systematic review and dose-response meta-analysis on the relationship between coffee intake and C-reactive protein (CRP) levels, an inflammation biomarker. They studied eleven previous studies involving a total of 61,047 participants from three different continents. These studies were chosen using the PubMed database. The selected studies had different findings: some showed a negative relationship between coffee and CRP levels, others showed a positive relationship while some showed no significant associations. The researchers analyzed the data from these studies using mixed-effects meta-regression models, with the volume of coffee consumed as the metric.
Regarding the discussion of results, there revealed to be considerable variation between the individual studies included in the meta-analysis. In three of the largest studies, it was found that the relationship between coffee consumption and CRP levels appeared to be different depending on the gender of the participant and their location. Women from Europe and the United States, as well as Japanese men, showed a decrease in CRP levels with increased coffee consumption. However, European men showed an increased inflammation marker. When all studies were considered together, no significant relationship between coffee consumption and CRP levels was found among all participants or when the data was stratified by gender or geographical location, showing the contradictory nature of the results noted in individual studies.
