Scientists are working hard to demonstrate the beneficial effects that coffee has on our health, such as easing muscular pain or gout symptoms, or increasing sex drive.
Others show that its effects are rather bogus, like the so-called energizing effect.
But others get back
to the subject, showing and - even more - explaining, coffee's harmful health effects. "Cafestol, a compound found in coffee, elevates cholesterol by hijacking a receptor in an intestinal pathway critical to its regulation", found a team from Baylor College of Medicine made of Dr. David Moore, professor of molecular and cellular biology, and Dr. Marie-Louise Ricketts, a postdoctoral student, together with Dr. Martijn B. Katan of Vriye Univeriteit Amsterdam, Institute for Health Sciences, The Netherlands. "In fact, cafestol is the most potent dietary cholesterol-elevating agent known."
Cafetiere (French press coffee), boiled Scandinavian brew and espresso present the highest amounts of this chemical, which is retained by paper filters employed in other brewing processes.
Decaffeinated coffee contains cafestol, since removing caffeine does not affect the other compound.
Katan had showed in a previous research that drinking five cups of French press coffee (30 mg of cafestol) daily leads in four weeks to an increase of the blood cholesterol level by 6 - 8 %, but how exactly does it do that remained unknown.
For a long time, Ricketts said she was stymied because of paradoxical effects of cafestol in the liver. Finding the fibroblast growth factor 15 (FGF 15) gene explained how cafestol affects the intestine's farsenoid receptor X (FXR), a bile acid receptor. "It is part of the body's own way of regulating levels of cholesterol," said Ricketts.
Tube and mice tests revealed that, inside the gut, cafestol turns on FXR and induces FGF15, which decreases the effects of three liver genes that regulate cholesterol levels.
Still, the researchers cannot say if cafestol itself reaches the liver, as even if active in the intestine, this organ is not directly involved in the bile acids' transport.