Human Metabolics Creates Chocoholics

Got a hankerin’ for a rich, creamy bite of chocolate? It might be a function of your metabolism, says a new study, “Human Metabolic Phenotypes Link Directly to Specific Dietary Preferences in Healthy Individuals” (Rezzi, et al, Journal of Proteome Research, ASAP Article 10.1021/pr070431h S1535-3893(07)00431-9).

The study, by Swiss and British scientists, has connected the preference for chocolate to a specific, chemical signature that might be programmed into the metabolic system and is detectable by laboratory tests. This discovery adds credence to a rapidly emerging discipline that could classify individuals based on their metabolic type, or metabotype. Metabolic status and food preferences can vary from person to person and even between different cultures. Proteome research, which focuses on characterizing the structure and function of the complete set of proteins produced by our genes, has allowed scientists to identify metabolic changes that occur when foods are digested. This could lead to methods to design healthier diets based on each individual’s needs.

Researchers studied 11 male volunteers who classified themselves as “chocolate desiring” and 11 volunteers who considered themselves “chocolate indifferent” in a controlled clinical study. Each subject ate chocolate or placebo over five days and had their blood and urine samples analyzed via using 1H NMR spectroscopy. The chocolate lovers exhibited a hallmark metabolic profile that involved low levels of low-density lipoprotein (LDL, “bad”) cholesterol and slightly elevated levels of albumin, a beneficial protein, whether or not they ate the chocolate samples. The researchers also found the behaviors and/or interactions of the gut microbes in the chocolate lovers were different from the other subjects, leading to a difference in the microbes’ functionality.

“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, study researcher and scientist with Nestlé Research Center in Switzerland. “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. 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.”

This approach can be applied to any population or diet, not just chocolate, and might lead to tests for determining a person’s metabolic type that could be performed as part of a blood or urine test during a regular visit to the doctor, Kochhar predicts. But, he notes, a reliable test of this type may be five years away, as more research is needed in this area.