The American Journal of
CLINICAL NUTRITION
Volume 65 Number 2 February 1997
Separate effects of the coffee diterpenes cafestol and kahweol on serum
lipids and liver aminotransferases
Rob Urgert, Natasja Essed, Guido van der Weg, Truus G Kosmeijer-Schuil,
and Martijn B Katan
Wageningen Agricultural University
Department of Human Nutrition
Wageningen, Netherlands
The coffee diterpene cafestol occurs in both robusta and arabica beans.
It is present in unfiltered coffee brews and raises serum concentrations
of cholesterol, triacylglycerols, and alanine aminotransferase in humans.
The effects are linear with the cafestol dose. Unfiltered coffee also
contains the related compound kahweol, which occurs only in the major
coffee strain arabica. The activity of kahweol is unknown. In a
randomized, double-blind crossover study, we gave 10 healthy male
volunteers either pure cafestol (61--64 mg/d) or a mixture of cafestol
(60 mg/d) and kahweol (48--54 mg/d) for 28 d. Relative to baseline
values, cafestol raised mean (±SEM) total serum cholesterol
concentrations by 0.79 ± 0.14 mmol/L (31 ±5 mg/dL), w-density-lipoprotein
(LDL) cholesterol by 0.57 ± 0.13 mmol/L (22 ± 5 mg/dL), fasting
triacylglycerols by 0.65 ± 0.12 mmol/L (58 ± 11
mg/dL), and alanine aminotransferase by 18 ± 2 U/L (all P < 0.01).
Relative to cafestol alone, the mixture of cafestol plus kahweol
increased total cholesterol by another 0.23 ± 0.16 mmol/L (9 ± 6 mg/dL)
(P = 0.08), LDL cholesterol by 0.23 ± 0.16 mmol/L (9 ± 6 mg/dL) (P =
0.09),triacylglycerols by 0.09 ± 0.10 mmol/L (8 ± 9 mg/dL) (P = 0.20),
and alanine aminotransferase by 35 ± 11 U/L (P = 0.004). Thus, the effect
of cafestol on serum lipid concentrations was much larger than the
additional effect of kahweol, and the hyperlipidemic potential of
unfiltered coffee mainly depends on its cafestol content. Both cafestol
and kahweol raised alanine aminotransferase concentrations, and their
hyperlipidemic effect thus seems not to be coupled with their effect on
liver cells. Am J Clin Nutr 1997;65:519-24.
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