For the first time, scientists have linked the all-too-human
preference for a food - chocolate - to a specific, chemical
signature that may be programmed into the metabolic system
and is detectable by laboratory tests. The signature reads
'chocolate lover' in some people and indifference to the popular
sweet in others, the researchers say.
The study by Swiss and British scientists breaks new ground
in a rapidly emerging field that may eventually classify individuals
on the basis of their metabolic type, or metabotype, which
can ultimately be used to design healthier diets that are
customized to an individual's needs. The study is scheduled
for publication in the Nov. 2 issue of American Chemical Society's
Journal of Proteome Research, a monthly publication.
Sunil Kochhar and colleagues studied 11 volunteers who classified
themselves as 'chocolate desiring' and 11 volunteers who were
'chocolate indifferent.' In a controlled clinical study, each
subject - all men - ate chocolate or placebo over a five day
period while their blood and urine samples were analyzed.
The 'chocolate lovers' had a hallmark metabolic profile that
involved low levels of LDL-cholesterol (so-called 'bad' cholesterol)
and marginally elevated levels of albumin, a beneficial protein,
the scientists say.
The chocolate lovers expressed this profile even when they
ate no chocolate, the researchers note. The activity of the
gut microbes in the chocolate lovers was also distinctively
different from the other subjects, they add.
"Our study shows that food preferences, including chocolate,
might be programmed or imprinted into our metabolic system
in such a way that the body becomes attuned to a particular
diet," says Kochhar, a scientist with Nestlé Research Center
"We know that some people can eat a diet that is high in
steak and carbs and generally remain healthy, while the same
food in others is unhealthy," he explains. "Knowing one's
metabolic profile could open-the-door to dietary or nutritional
interventions that are customized to your type so that your
metabolism can be nudged to a healthier status."
Researchers have known for some time that metabolic status
and food preferences can vary from person to person and even
between different cultures. The recent growth of the new field
of proteome research, which focuses on characterizing the
structure and function of the complete set of proteins produced
by our genes, has allowed scientists to gain a deeper understanding
of the metabolic changes that occur when foods are digested,
"There's a lot of information in metabolism that can be used
to improve health and this information is just now being explored
and tapped," the researcher says.
In the future, a test for determining one's metabolic type
could be performed as part of a blood or urine test during
a regular visit to the doctor, Kochhar predicts. But a reliable
test to measure one's metabolic type may be five years away,
as more research is still needed in this area, he notes.
Women were not included in the current study in order to
avoid any metabolic variations linked to the menstrual cycle,
which has been shown in studies by others to influence metabolic
differences, Kochhar says. But the researchers plan to include
women in future clinical trials on metabolic responses to
chocolate to determine if there is a gender-specific response
to the treat.
In addition to providing a better understanding of individual
metabolic types, the current study could also lead to the
discovery of additional biomarkers that can identify new health
benefits linked to chocolate and other foods, says Kochhar,
whose research was funded by Nestlé.