Coffee Consumption Increases the Antioxidant Capacity of Plasma and Has No Effect on the Lipid Profile or Vascular Function in Healthy Adults in a Randomized Controlled Trial.

BACKGROUND: Coffee, a source of antioxidants, has controversial effects on cardiovascular health. OBJECTIVE: We evaluated the bioavailability of chlorogenic acids (CGAs) in 2 coffees and the effects of their consumption on the plasma antioxidant capacity (AC), the serum lipid profile, and the vascular function in healthy adults. METHODS: Thirty-eight men and 37 women with a mean ± SD age of 38.5 ± 9 y and body mass index of 24.1 ± 2.6 kg/m(2) were randomly assigned to 3 groups: a control group that did not consume coffee or a placebo and 2 groups that consumed 400 mL coffee/d for 8 wk containing a medium (MCCGA; 420 mg) or high (HCCGA; 780 mg) CGA content. Both were low in diterpenes (0.83 mg/d) and caffeine (193 mg/d). Plasma caffeic and ferulic acid concentrations were measured by GC, and the plasma AC was evaluated with use of the ferric-reducing antioxidant power method. The serum lipid profile, nitric oxide (NO) plasma metabolites, vascular endothelial function (flow-mediated dilation; FMD), and blood pressure (BP) were evaluated. RESULTS: After coffee consumption (1 h and 8 wk), caffeic and ferulic acid concentrations increased in the coffee-drinking groups, although the values of the 2 groups were significantly different (P < 0.001); caffeic and ferulic acid concentrations were undetectable in the control group. At 1 h after consumption, the plasma AC in the control group was significantly lower than the baseline value (-2%) and significantly increased in the MCCGA (6%) and HCCGA (5%) groups (P < 0.05). After 8 wk, no significant differences in the lipid, FMD, BP, or NO plasma metabolite values were observed between the groups. CONCLUSIONS: Both coffees, which contained CGAs and were low in diterpenes and caffeine, provided bioavailable CGAs and had a positive acute effect on the plasma AC in healthy adults and no effect on blood lipids or vascular function. The group that did not drink coffee showed no improvement in serum lipid profile, FMD, BP, or NO plasma metabolites. This trial was registered at registroclinico.sld.cu as RPCEC00000168.

GC/MS method to quantify bioavailable phenolic compounds and antioxidant capacity determination of plasma after acute coffee consumption in human volunteers.

Coffee, a source of chlorogenic acids (CGAs), is recognized for preventing chronic diseases associated with oxidative stress. Therefore, sensitive, selective and easy access methods for the determination of the bioavailability and antioxidant function in vivo are required in clinical studies. The aim of this work was to validate a GC/MS method to quantify caffeic acid (CA) and ferulic acid (FA) and to apply different methodologies to determine the antioxidant capacity of plasma after the acute consumption of 420mg of CGAs provided by 400mL of coffee. The intervention was performed in 20 adults (6 men and 14 women) with a mean±SD age of 35.7±9.0 and body mass index of 22.1±1.6kg who were assigned to 2 groups: a control group and a group that consumed coffee. The validated analytical GC/MS method was exact, precise and selective. The selected derivatizing reagent was N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide with 1% tertbutyldimethylchlorosilane (MTBSTFA+1% TBDMSCl). The method was reproducible, and the limit of detection (LOD) was 3nM for CA and 5nM for FA. CA and FA were detected in plasma 1h after coffee intake and were undetectable in the control group. Compared to the baseline values, the antioxidant capacity of plasma significantly increased when it was measured by ferric reducing antioxidant power (FRAP) (6.67%; P<0.001) and by oxygen radical absorbance capacity (ORAC) (7.16%; P<0.05). The in vitro and ex vivo experiments on plasma with CA and FA showed a significant increase of the antioxidant activity (P<0.05) as well as delay of LDL oxidation (P<0.001). The method validated by GC/MS was proposed as an alternative for evaluating the bioavailability of ACG after acute coffee intake. The need for in vitro methodologies was demonstrated to determine the antioxidant activity.