MedicalResearch.com Interview with:
Suzan Wopereis, Ph.D.
TNO, Microbiology and Systems Biology Group
Zeist, The Netherlands
Medical Research: What is the background for this study? What are the main findings?
Dr. Wopereis: For the first time we could demonstrate the very subtle start of negative health effects caused by a high calorie snack diet in healthy men. We already knew about the negative consequences of such diets from so called epidemiologic studies. In such studies, scientists compare large populations (thousands of people) to better understand disease development. For example, by comparing obese populations to a lean population, scientists could define various steps in the disease development related to obesity, like high cholesterol, onset of inflammation, high blood pressure, high glucose, etc. Yet, the early deviations from health were difficult to study because human metabolism (the way we digest and metabolize our meals from a biochemical viewpoint) is very flexible and able to efficiently deal with all kinds of daily stressors, such as a meal or intensive exercise. So, at TNO we decided to exploit this flexibility by giving our healthy volunteers a ‘challenge test’, in the form of a high-fat milkshake. Next, we studied how multiple aspects of their metabolism react to such a challenge test. We showed that a snack diet for 4 weeks reduced many aspects of flexibility of our healthy men, thus indicating very early changes in health. Both the high-fat challenge test and the integral study of many different outcomes form a novel approach of what “healthy” really means.
In the study we used two groups of male volunteers. One group of 10 healthy male volunteers and one group of 9 male volunteers with Metabolic Syndrome, who had a combination of 2 or more risk factors that raises your risk for heart disease and other health problems (unhealthy cholesterol levels, high blood pressure, high blood sugar, high blood lipids, and abdominal fat). In other words, subjects with Metabolic Syndrome have a suboptimal health condition. Both groups received a high-fat milk-shake, and before and up to 8 hours after consumption of this metabolic challenge-test, blood samples were taken. In these blood samples, 61 different biomarkers were measured, such as cholesterol and blood sugar. These 61 biomarkers were used for a thorough health assessment of these 2 groups in response to the challenge test. We noted that biochemical processes related to sugar metabolism, fat metabolism and inflammation function abnormal in subjects with Metabolic Syndrome. The next step was to provide the 10 healthy male volunteers with a snack diet for 4 weeks. On top of their normal diet they had to consume an additional 1300 kcal per day, in the form of sweets and savory products such as candy bars, tarts, peanuts, and crisps. After these 4 weeks the response of the same 61 biomarkers to the challenge test was evaluated. Here, we observed that signaling molecules such as hormones regulating the control of sugar and fat metabolism and inflammation were changed, resembling the very subtle start of negative health effects. Without the use of the challenge test, we would not have been able to observe that even this short period of overfeeding induces changes in the metabolism of healthy people that resemble what happens in people with metabolic syndrome.