Most individuals are who are
aware of the appetite suppressing properties of coffee could understand why so
many studies have shown that coffee drinking is associated with weight-loss. In
fact, the role of coffee has been investigated in studies relating to obesity
and the development of diabetes. Despite this wealth of research, few studies
have addressed the underlying mechanisms that may be responsible for these
effects. Now a recently published study suggests drinking more than five cups
of coffee a day may have the opposite effect.
The study, which was published in the Journal of Agriculutural and
Food Chemistry was an animal study which looked at the result of a dietary
intervention in three groups of mice during the course of twelve weeks. The
three groups were: mice on a standard diet, mice on a high fat diet and mice on
a high-fat diet with additional chlorogenic acid (CGA). The addition of CGA was
equivalent to five cups of coffee. The key findings indicated that mice that
were given both a high fat diet and CGA had a higher lipid content and more
steatosis than mice that were only fed a high fat diet. Based on this, the
researchers concluded that excessive supplements of CGA had the opposite
effects for weight loss. In addition to that, their results suggested that
there was a dose response association between the amount of CGA that a mouse
consumed, and their insulin resistance.
This is in stark contrast to
previous studies that have indicated that coffee, whether it contains caffeine
or not, is related to weight-loss and a lower risk of development of type 2
diabetes. However, those studies have not addressed what particular chemical
ingredient in coffee would have the potential to lead to this treatment.
It is understandable that the
current study looked at CGA, as it is abundantly found in coffee and has been
associated with increasing insulin sensitivity and reducing body fat
accumulation. However, it is less clear how applicable their conclusion is to
humans. Perhaps what stands out are the portions included for mice, which were
calculated according to their weight. Although the researchers have stated that
their estimations for this effect to occur are five to six cups of coffee per
day, it is not clear what size of cups they are referring to. Given that there
is a wide range of coffees available, whether it be large lattes or small black
espressos, we are finding it a bit challenging to translate these findings into
measurements related to humans. As such it makes it difficult to understand
what group would be at risk of drinking five cups a day.
Perhaps the value of the study
lies in the way it changes how the relationship between coffee and weight-loss
as well as insulin resistance is perceived in research. Clearly, more in depth
studies considering the direction of the relationships found to date as well as
factors affecting the underlying mechanisms are needed. The full study can be
found here.