Dietary fatty acids, including oleic acid (OA), which is a cis monounsaturated fatty acid or MUFA, and palmitic acid (PA), which is a saturated fatty acid, are an important focus of Kien’s work. In particular, he and his colleagues aimed to learn more about how these fatty acids might affect the body’s response to insulin — the hormone essential to our body’s metabolism of sugar. Type 2 diabetes is a condition usually characterized by insulin resistance, meaning the body cannot metabolize blood sugar at the normal rate.
In order to study how the body metabolizes different dietary fatty acids, Kien and colleagues developed two experimental diets. One, which was high in PA, mimicked the “typical” American diet; the other was a high OA diet, consistent with what is called a Mediterranean diet. All study participants were first fed a baseline diet, which was lower in fat and followed usual recommendation for a low saturated fat diet, for one week and then were randomized to one of the experimental diets. After a week of the diet, the researchers took skeletal muscle biopsies and blood tests to determine the impact of the nutritional fats on body fat composition.
“The most unique conclusion derived from this study is that the PA and OA content of various lipids within muscle or blood, including those originating in the mitochondria — the energy-producing organelle of the cell — respond rapidly to changes in dietary fat composition,” said Kien.
In addition, Kien and his co-authors, who maintain that their data are preliminary, found that “our results imply that the fatty acid composition of muscle lipids and acylcarnitine metabolites both can be used as biomarkers of dietary fatty acid composition.” The study also showed that modification of dietary fat composition for only one week had significant effects on serum cholesterol; for example, the LDL cholesterol fell 16 mg/dl during the low PA/high OA diet. “This type of change could have an impact on clinical practice if it occurred shortly before a scheduled medical visit,” said Kien.
Since the completion of these studies, Kien has been awarded two National Institute of Health grants to pursue these findings in much greater detail with emphasis on measuremements of insulin sensitivity and using the approaches of genomics and metabolomics. His collaborators at UVM on the latest grant are Janice Bunn, research assistant professor of mathematics and biostatistics and research associate professor of rehabilitation and movement science; Naomi Fukagawa, M.D., professor of medicine; Dwight Matthews, Ph.D., professor and chair of chemistry and professor of medicine; and Matthew Poynter, M.D., associate professor of medicine. Fukagawa is a co-author on the Obesity study.
For more information about Kien’s studies, email [email protected] or call 802-656-9093.