Alterations in Abdominal Blood Flows After Drinking Coffee

Coffee exerts beneficial effects on health, such as suppressing type 2 diabetes, cardiovascular disease, and fatty liver. Coffee also relieves headaches by the caffeine component decreasing blood flow in the cerebral arteries. Caffeine is also used to treat apnea in premature infants, but blood flow in the superior mesenteric artery (SMA) decreases as a side effect. However, whether drinking coffee decreases abdominal blood flows in adults remains uncertain. If drinking coffee decreases SMA blood flow in adults, subsequent blood flows via the portal vein (PV) to the liver might also decrease, which could be a contributor to the beneficial suppression of fatty liver. The present study aimed to clarify hemodynamics in the SMA and PV under fasting conditions after drinking coffee or water in 32 healthy young men (mean age, 21 ± 1 years). Flow volume decreased on sonography 30 min after drinking coffee in the SMA (median -13.4%, interquartile range [IQR] -18.6% to -9.6%; p < 0.001) together with an increase in pulsatility index (median 9.0%, IQR -1.1% to 14.5%; p < 0.001), and a decrease in PV (median -11.3%, IQR -14.5% to -5.3%; p < 0.001). These phenomena were observed 90 min after drinking coffee and were particularly prominent in habitual low caffeine consumers, but were largely absent after drinking water. Drinking coffee decreases SMA and PV blood flows in adults.