Fat Quality Also Significant for Blood Glucose Levels


The dietary intake of saturated fatty acids (SFAs) from food of animal origin may alter brain function and sleep. This is a conclusion of a study carried out by the Department of Internal Medicine, University of Tübingen. According to this study, increased intake of milk fat leads to elevated blood glucose levels, reduced brain activity and a decrease in physical activity. This is not the case with a comparable dietary intake of canola oil (rapeseed oil), which is rich in monounsaturated fatty acids (MUFAs). The researchers point out that fats containing high amounts of saturated fatty acids increase the risk for diabetes and reduce brain performance.

Today, the abundance of foods available with a high energy density, combined with physical inactivity, is seen as one of the main reasons for obesity and diabetes mellitus type 2. These diseases constitute a great challenge for the health care system. Along with the total fat quantity, fat quality also appears to play a crucial role. The research group of Dr. Anita Hennige from the Department of Internal Medicine, University of Tübingen (Medical Director Prof. Dr. med. Dr. h.c. Hans-Ulrich Häring), in cooperation with the German Center for Diabetes Research, compared the effects of an equivalent calorie intake of canola oil and milk fat on blood glucose levels, physical activity, brain performance and sleep behavior.
From a nutritional-physiological perspective, canola oil is a high-value edible oil, since it contains a high proportion of monounsaturated fatty acids (MUFAs) and is especially low in saturated fatty acids (SFAs). Milk fat, which is an animal fat, essentially consists of saturated fatty acids, the main component being palmitic acid.

The brain, too, likes good fat
Nutrition scientist Dr. Tina Sartorius demonstrated in mouse studies that foods with very high SFA content lead to elevated blood sugar levels and impaired insulin action in the brain. She pointed out: “These overweight mice show reduced locomotion, impaired brain activity and altered sleep-wake patterns. By contrast, MUFAs do not lead to changes in the blood glucose levels, even though these mice are likewise overweight. They remain physically active and their sleep is not disturbed.”

The research team provided evidence for similar effects in humans. Even though the test subjects did not show any significant differences in body weight or blood glucose levels, after a three- month diet of yoghurt enriched with either milk fat (the SFA group) or canola oil (the MUFA group), brain activity was reduced in those persons who had eaten an increased amount of saturated fat.
SFAs particularly affect regions of the brain that are responsible for the sense of satiety, memory, and locomotion activity patterns. In summary, according to Hennige, one can say that too much fat in food will always lead to obesity. “However,” she continued, “only the SFAs contained in animal fats have a negative effect on blood glucose levels, brain activity and physical activity, which in turn leads to further weight gain.”

The results of this study are currently being published in Diabetes, the journal of the American Diabetes Society.

Further information:
University Hospital Tübingen
Department of Medicine, Division of Endocrinology and Diabetology, Angiology, Nephrology and Clinical Chemistry
Assistant Professor Anita M. Hennige, MD
Phone: +49 (0)7071/ 29-8 05 97 (office), +49 (0)7071/29-8 27 11 (via the gate house)

Original publication:
Tina Sartorius, Caroline Ketterer, Stephanie Kullmann, Michelle Balzer, Carola Rotermund, Sonja Binder, Manfred Hallschmid, Jürgen Machann, Fritz Schick, Veronika Somoza, Hubert Preissl, Andreas Fritsche, Hans-Ulrich Häring, and Anita M. Hennige: “Monounsaturated Fatty Acids Prevent the Aversive Effects of Obesity on Locomotion, Brain Activity, and Sleep Behavior.” Diabetes 61:1–11, 2012, in press.
DOI: 10.2337/db11-1521