Cafestol and kahweol: Filtering out cholesterol boosters
Coffee drinkers concerned about cholesterol weren't happy about some early study results showing that coffee seems to increase cholesterol levels, and "bad" LDL cholesterol levels in particular. But upon closer inspection, the bad news turned out to be not so bad, because the cholesterol-raising effect seems to be limited to coffee that hasn't been filtered, which includes Turkish coffee, coffee brewed in a French press, and the boiled coffee consumed in Scandinavia.
The cholesterol-raising ingredients in coffee are oily substances called diterpenes, and the two main types in coffee are cafestol (pronounced CAF-es-tol) and kahweol (pronounced KAH-we-awl). They are present either as oily droplets or in the grounds floating in the coffee. But a paper filter traps most of the cafestol and kahweol, so coffee that's been filtered probably has little, if any, effect on cholesterol levels.
The best evidence is for paper filters, but an interesting study published in 2011 showed that filtering methods used in Singapore (the so-called sock method, which uses a cotton-nylon cloth) and India (metal mesh) were also effective at trapping cafestol.
Espresso contains more cafestol and kahweol than paper-filtered coffee, but because it is consumed in smaller amounts, it may not have much of an effect on people's LDL level.
There is a twist to this aspect of the coffee story, because cafestol and kahweol may also have some health benefits that are lost when they're filtered out. The research is in the preliminary stages, but cafestol and kahweol could have some anticancer effects and be good for the liver.