A molecular picture of chocoholics
look at the effects diet is having on meta bolic health,” he says. On the basis of a survey of the chocolate preferences of 75 males, Kochhar and his team selected 22, half of whom were “chocolate-desiring” and the rest “chocolate-indifferent”, and placed them on a defined diet for 5 days. (Females were excluded to avoid the confounding effects of hormonal fluctuations.) On days 2 and 4, each subject was given either 50 g of chocolate or 50 g of bread. On day 4, those subjects who received chocolate on day 2 received bread, and vice versa. Blood samples
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Intensity (a.u.)
SUNIL KOCHHAR
metabolic differences between the chocolate-desiring and chocolate-inTo chocolatiers, there are but two types different groups, as well. For example, of people: those who love chocolate and higher levels of phenylacetylglutamine those who don’t. and citrate in the chocolate-desiring In this issue of JPR (pp 4469–4477), group suggest that these individuSunil Kochhar and colleagues at the als may regulate the citric acid cycle Nestlé Research Center (Switzerland) slightly differently than those who and Imperial College London set out to don’t fancy a daily dose of chocolate. Eldistinguish the two populations at the evated levels of carnitine and N-acetylmolecular level. The team developed a carnitine in the chocolate-indifferent novel approach they call “nutrimetab group, however, suggest differences in onomics” to correlate metabolic lipid metabolism in this population. phenotypes with a behavioral pheUrine analyses also highlighted difnotype—namely, an affinity for rich, ferences in gut microflora between the creamy chocolate. two study populations—or at Metabonomics is a disleast, in their behaviors and Residual water cipline that uses metabolic interactions with their hosts, Lipoproteins (CH2) profiles of bodily fluids such says Kochhar. The study as blood plasma and urine identified differences in the Lipoproteins (CH3) to understand drug toxicity, metabolism of niacin and of Lipids Lipids pharmacological responsivearomatic compounds such (CH2CH2CO) (C=CCH2C=C) Lipids ness, and other biological as 4-hydroxyphenylacetate (CH2CH2CO) Lipids events. Nutrimetabonomics and 2-hydroxyhippurate, for (CH2C=C) Unsaturated lipids is an offshoot of that pursuit, instance. All of these findings Glucose and Choline Lipids Alanine (CH2CO) amino acids Valine says Kochhar, in which the point to differences between Albumin �-Glucose LDL /HDL cholesterol lysyl Lactate �-Glucose Glutamine tools of metabonomics (in the two groups in the functhis case, 1H-NMR spectrostionality of gut microflora. copy) are applied to examine The bottom line, Koch5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 the effects that diet has on har says, is the realization 1H chemical shift (ppm) metabolism—and ultimately that diet leads to a sort of on health. metabolic “imprinting”. In “We at Nestlé are using other words, the body (and metabonomics to understand its associated microflora) apsubclinical situations” such pears to become attuned to a as gut discomfort and inparticular diet. This finding flammation, Kochhar says. can have both positive and These conditions do not rise negative health consequencIt’s all in the spectrum. Researchers discovered that the metaboto the level of a true disease, es—but which also could nomes of subjects who desire chocolate were different from those of and thus they are unlikely ultimately open the door to subjects who are indifferent to it. either to be brought to a novel dietary regimes. “If we physician’s attention or to be know how we can influence properly treated if they are, he explains. were collected at five time points after gut microflora, then we can design a “Nutrition is the only way to deal with chocolate or bread intake; urine samnutritional regime that can trick our these ‘diseases’, but you need to pick up ples were collected daily. microflora to harvest more or less enthese [metabolic] deviations early on.” Upon statistical analysis, the plasma ergy,” he explains. Therefore, one could Unfortunately, such deviations can metabolic profiles of those who desired nudge a person’s metabolism one way be difficult to detect. “If you are taking chocolate could be distinguished from or another. drugs like statins, the change in metabthose who were indifferent to its charms. Kochhar stresses that although olism is huge,” Kochhar says. “But when The chocolate-indifferent individuals this study involved chocolate—it was tended to display higher levels of lipid– you want to look at metabolic health for conducted at Nestlé, after all—the dietary applications, which is a mix of lipoprotein complexes, mostly in the nutrimetabonomics approach can many different micro- and macromolform of plasma low-density lipoproteins be applied to any diet or population, ecules, the effect is very subtle.” As a (LDLs). Those in the chocolate-desiring perhaps to assess the benefits of the result, a key part of the study involved group had lower plasma levels of lipoMediterranean diet and lifestyle or of statistical analyses to tease out those proteins, whereas the level of albumin, a pre- and probiotics or to lend scientific molecules whose abundances correlate protein whose roles include ferrying free heft to the question of whether coffee or (either positively or negatively) with a fatty acids around in the bloodstream, tea is healthier. “At the end of the day, particular behavioral class. “You need was slightly higher. metabolism is the key,” he says. very special mathematical models to Urinary analyses identified several —Jeffrey M. Perkel
Journal of Proteome Research • Vol. 6, No. 11, 2007 4105
