matches all products of metabolism in a single specimen against a large database of chemical inventory samples, providing an unprecedented catalog of molecular symbols generated by by consuming food or by processing it in our intestines.
Widely used, the authors say, this new method could significantly expand the understanding of chemical sources in a wide range of human, animal and environmental samples.
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Untargeted mass spectrometry
“Untargeted mass spectrometry is a very sensitive technique that allows the detection of hundreds to thousands of molecules that can now be used to create dietary profiles of individuals,” Pieter said. Dorrestein, PhD, director of the Collaborative Mass Spectrometry Center for Innovation at the University of California San Diego’s Skaggs School of Pharmacy and Pharmaceutical Sciences.
“The expanded ability to understand how what we eat transforms into metabolic products and by-products has a direct impact on human health. We can now use the This approach to empirically gather dietary information and understand the relationship to clinical outcomes is now possible to link dietary molecules to health outcomes not at once. which all at once, which was not possible before.”
What are Metabolomics?
Metabolomics involves the comprehensive measurement of all metabolites in biological specimens. Metabolites are substances, usually small molecules, that are produced or used when an organism breaks down food, drugs, chemicals, or its own tissues. They are products of metabolism. The study also used a related technique, measurementto measure the genetic material in biological samples and to characterize the microorganisms present.
Current metabolomics studies only annotate or identify 10% of the molecular features in the sampled specimens, leaving 90% of the material unknown. The new method uses reference data-driven (RDD) analysis to match metabolic data obtained from tandem mass spectrometry or MS/MS (an analytical instrument that measures molecular weight using two analyzers instead of one) than the metadata annotated data is the MS/MS Reference Library.
Essentially, each molecule is stripped of electrons to make it electrically charged. The charged ion is balanced with a very sensitive balance, then broken into pieces and those pieces are weighed, creating a unique fingerprint for each molecule.
These sets of fragments or “fragmentations” can be matched between the sample being analyzed and the reference database. However, so far this process has been fraught with challenges.
In the new work, the researchers investigated thousands of foods contributed by people around the world as part of the Global FoodOmics initiative launched at UC San Diego seven years ago, building on the success of the Project. American Gut Citizen Science Project/Microsetta Initiative. The scientists increased their data output more than 5 times compared with conventional techniques. Most importantly, the new method allows the use of untargeted metabolites for dietary determination based on fecal or blood samples.
The authors say the RDD analysis allows them to analyze dietary patterns (e.g., vegan versus omnivorous) and consumption of specific foods, and in general, match the data to any any existing reference databases.
“This advance is important because traditional methods of measuring diet, such as food diaries or food frequency questionnaires, are a pain to fill out and very difficult to implement. exactly,” said co-author Rob Knight, PhD, director of the Center for Microbiome Innovation at UC San Diego.
“The potential to read out the diet from a direct sample has huge implications for research in populations such as people with Alzheimer’s disease, who may not be able to remember or interpret what they ate. And in wildlife conservation apps. Good luck getting a cheetah or gorilla, just to name two of the hundreds we’re studying, to fill out the food diary.”
Of particular concern, Dorrestein and Knight say, is that large improvements in the number of molecules in the blood or stool can be explained when food items are population-matched, such as matching foods from Italy with people from the Cilento peninsula where UC San Diego scientists are collaborating on a study of long-lived people.
“This really shows how important it is to get both food and clinical samples from people around the world to understand how our molecules and bacteria work together to improve or degrade.” reduce our health based on the diet we eat,” Knight said.
“This study also points to a path towards using RDDs to explain dark matter in our metabolic bodies,” added Dorrestein, “not just in terms of diet, but also in terms of exposure with chemicals from the clothes we wear, the drugs we take, the beauty products we use and the environment we’re exposed to. It will really allow us to explore chemical connections. learning between ourselves and the world we live in.”
Source: Eurekalert
