Metabolic obesity

Evidence from NMR spectroscopic studies of individual metabolic profiles would suggest that the way our bodies digest and process nutrients in the food we eat is different for every person and could ultimately affect overweight and obesity problems.

Nutrition scientists and food chemists at the Technische Universität München have joined forces with other experts to found the Munich Functional Metabolomics Initiative, an interdisciplinary network for driving research in the field. Their recent focus has been the notion that, despite our being 99.9% identical and yet individual differences give rise to superficial traits as well as more hidden differences, such as those in our personal metabolism. Understanding these differences is particularly important for uncovering the mechanisms underlying conditions such as diabetes or cardiovascular disease.

The team has initiated a study called HuMet in which fifteen healthy young male volunteers were closely scrutinized for four days. The men had to fast, eat and drink various types of standardized nutrition, and submit to a variety of physical tests. All the while various blood, urine, and breath samples were taken. Hannelore Daniel, professor of nutritional physiology, and Hans Hauner, a nutritional physician at the TUM, carried out the nutritional protocol and test procedures, while Thomas Hofmann carried out chemical analysis on sample.

"In general, all people react similarly to specific nutritional components," explains Daniel, "but there are big differences in their responses." For example, when a test subject is given a certain amount of glucose, his or her blood sugar level rises and then falls again. But preliminary data from the HuMet study have revealed some astonishing details. "Obviously all values will rise", Daniel says. "The blood sugar level must go up. But it is very interesting to observe the differences in the way the levels rise and fall off again. It took four hours for the test subjects' blood sugar levels to come back into alignment with each other." The researchers hopes to be able to determine how wide is the variance between individuals, with Hofmann's team specialising in liquid chromatography-tandem mass spectrometry and NMR spectroscopy.

"We need to develop the methods further to do justice to the complexity of the body's metabolism. Today, we are at a level comparable to that of digital cameras in the 1980s," explains Hofmann. "We must increase the resolution of our analytical camera to obtain a sharp image of all metabolic by-products." And if we want to describe metabolic dynamics next, we will need to make a short movie. "For this we want to automate our procedure so that it will deliver a large number of high-resolution images over a short period of time. These can then be combined into a sequence, analogous to a flip-book."

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