18/12/08 Recent research by TNO, the Dutch institute for applied scientific research, shows that changes in diet have a marked effect on gene expression in fat tissue. In the study, scientists found that fat cells in lean and overweight men react distinctly different to changes in their diet. This result confirms the growing insight that fat tissue responds actively to dietary changes. It also increases our understanding of how fat tissue acts in diseases related to obesity, like diabetes type 2. The findings appeared in the December issue of Genes and Nutrition.

In this pioneering study, TNO scientists analyzed the activity of genes in fat tissue biopsies taken from human volunteers. Senior scientist human physiology, Henk Hendriks of TNO explains the novel nature of the study’s findings: ”For the first time, we show that a short-term diet change has an effect on the activity of genes that play a role in inflammatory processes in fat tissue of people who are overweight. The technique is an example of nutrigenomics research, and it allows us to investigate the effect of complex mixtures of functional food ingredients on fat tissue. The first findings show that genes in fat tissue are sensitive to diet changes. The result also strengthens our hypothesis that fat tissue is actively involved in the development of obesity-related disease.”

The discovery is interesting as it could lead to develop better dietary strategies for keeping slightly overweight people healthy for a longer period of time. More research will be needed to confirm and expand the findings.

In the cross-over study, 10 lean and 10 overweight men consumed a specially designed margarine-like spread and a control spread for nine days. The special spread and the control spread differed only in their fatty acid composition. The amount of fat supplied in the spread was similar for both interventions.

Samples of subcutaneous fat tissue from the abdomen were taken from the volunteers, and the activity of the genes was analyzed. The activity of the genes in these samples differed significantly between lean and overweight individuals. In lean people, the special spread resulted in lower expression of genes related to energy metabolism. In the majority of overweight men, the special spread resulted in lower activity of inflammatory genes and higher activity of lipid metabolism genes. Individual responses in the overweight volunteers were variable. These responses correlated to the waist-hip ratio (the ratio between the circumferences of the body at these points) and fat percentage in these people.

In nutrigenomics research, large-scale gene expression analysis (transcriptomics) and large-scale metabolite analysis (metabolomics) strategies are used to study the effects of dietary ingredients on human health. TNO has a globally leading position in nutrigenomics research and collaborates with academic consortia and with the food industry to better understand the complex effects of dietary components on human physiology. This will help governments to better inform the public about diet and lifestyle and will help food companies obtain stronger proof for positive health effects of their products.