. 2013 Jan 24;35(6):2183–2192. doi: 10.1007/s11357-012-9509-4

Table 1.

The effect of dietary supplementation with coffee on serum levels of caffeine and hydroxycinnamic acid metabolites in aged rats

Percentage of coffee in diet (human equivalent in cups)	Serum level (ng/mL)
Percentage of coffee in diet (human equivalent in cups)	Caffeine	Caffeic acid	Ferulic acid	Hippuric acid
0.000 (0)	0.173 ± 0.03^a	0.00 ± 0.00^a	1.04 ± 0.79^a	94.84 ± 23.07^a
0.165 (3)	0.274 ± 0.10^a	0.00 ± 0.00^a	13.77 ± 9.34^a	267.28 ± 102.11^a,b
0.275 (5)	0.122 ± 0.03^a	0.34 ± 0.34^a	16.62 ± 12.06^a	361.53 ± 95.05^b,c
0.550 (10)	14.55 ± 8.30^a	3.64 ± 1.14^b	3.20 ± 0.73^a	502.20 ± 97.94^b,c
0.825 (15)	112.44 ± 56.63^b	8.16 ± 1.77^c	6.13 ± 2.77^a	552.58 ± 93.32^c

Data are presented as means ± SEMs. Values in each column with different superscript letters are significantly different (Fisher’s LSD; p < 0.05)