Preliminary findings from several animal
experiments and some human studies have shown that both green coffee
extract and its major phenolic compound chlorogenic acid have shown
thermogenic fat-burning effects, as well as other health promoting
actions. For example, a green coffee extract
prevented weight gain and fat accumulation in mice. Green coffee
extract has been shown to contain significant amounts of chlorogenic
acid, and other polyphenolic compounds with anti-oxidant activities.
Animal studies have reported that chlorogenic acids appear to target
fat stores in the liver. One of the key questions is whether these
bioactive nutrients are bioavailable when humans ingest green coffee
extract. French researchers studied the pharmacokinetic profile after
ingestion of green coffee extract in healthy men and women. Subjects
consumed 2 capsules (400 mg) of decaffeinated green coffee extract
containing 170 mg of chlorogenic acids. Blood samples were measured
sequentially for 8 hours and urine samples collected to estimate
bioavailabilty of various compounds in green coffee extract. The total
bioavailability varied from person to person from as little as 7.8% to
as high as 72% with an average of 33%. Several different chlorogenic
acids were detected in blood after ingestion including caffeoylquinic,
ferulic, caffeic, and isoferulic acids. The significant increase in
ferulic acid is interesting because it has been shown to stimulate
nitric oxide bioavailability and have a positive effect on vascular
dilation and blood pressure. The authors conclude that the major
compounds in green coffee extract are highly absorbed and metabolized
in humans.
Farah A, Monteiro M, Donangelo CM, Lafay S. Chlorogenic Acids from
Green Coffee Extract are Highly Bioavailable in Humans. J Nutr. 2008
Dec;138(12):2309-2315.
