2008 Major Accomplishments…
Obesity & Metabolism
High Fructose Consumption Increases Intra-Abdominal Fat
Unit scientists, in collaboration with UC Davis investigators, found that consuming large amounts of beverages sweetened with the sugar fructose over time reduces resting metabolic rate and lowers use of fat calories for energy, and is associated with increased body weight and intra-abdominal fat (the fat that surrounds organs inside the body). Studies are currently underway that explore these questions at lower intakes of fructose and high fructose corn syrup that better match those observed in the majority of the U.S. population.
Post-Meal Blood Fructose Patterns Differ Markedly from Glucose and are Highly-Variable in Humans
Working with UC Davis and University of Pennsylvania collaborators, it was found that postprandial peak levels of blood fructose following a high-fructose test meal are substantially lower compared to blood glucose peaks following a high-glucose meal, likely reflecting differential liver uptake and metabolism of the sugars. Remarkable person-to-person variability in the post-meal levels of blood fructose was observed, highlighting that individuals in the population differ substantially in the way they cope metabolically with this common sugar.
School Meals & Body Fat in Adolescent Girls
In Asian-American 6th grade girls, participation in school free and reduced meal programs (FRMPs) was associated with greater percent body fat. Further studies will be required to understand if the association is secondary to other as-yet unidentified factors or if FRMP meal composition, quantity, or dietary behaviors underlie this observation.
Evidence that Zinc Regulates Weight Gain and Body Fat Accumulation
Mice engineered to lack a specific cell zinc transporter (Znt7) were found to gain less weight and body fat when fed a high fat diet, providing novel evidence that zinc metabolism could regulate energy balance.
New Metabolomic Profiling Techniques
New analytical methods were developed for rapidly profiling 140 metabolites including omega-3 fatty acids by mass spectrometry instrumentation. These methods are being applied to human blood samples to identify metabolite “signatures” reflective of health and disease, and to study the impact of changes in dietary fat.
Measuring B12 Absorption in Humans
Unit scientists working with investigators at the Lawrence Livermore Labs validated a new, highly-sensitive method to measure vitamin B12 absorption in humans, using ultra-low dose radiolabeled vitamin B12 and accelerator mass spectrometry.
Characterization of Unique Genes Found in Fat Cells and Neurons
Recent evidence points to the presence of unique genes, Tusc5 and SNCG, that are expressed in both fat cells (adipocytes) and peripheral nerves, and that are regulated by cellular pathways known to be responsive to metabolic shifts. These findings may have implications for poor nerve function (neuropathies) observed in many obese and diabetic persons, and suggest that these genes and pathways could be responsive to changes in nutritional status.