Dietary intake of n-3 PUFAs modifies the absorption, distribution and bioavailability of fatty acids in the mouse gastrointestinal tract

Qin Yang, Shunhe Wang, Yunqi Ji, Haiqin Chen, Hao Zhang, Wei Chen, Zhennan Gu, Yong Q. Chen

Dietary polyunsaturated fatty acids (PUFAs), especially n-3 PUFAs, are important for human health. The intestinal tract, a location that is heavily colonized by microorganisms, is the main organ for absorbing fatty acids. The purpose of this study was to analyze the effects of dietary n-3 and n-6 PUFAs on the distribution of different types of fatty acids and their bioavailability along the gut. Mice were fed for a week with experimental diets containing high n-3 or high n-6 fatty acid levels. Blood was collected at different time points, and after 7 days the mice were euthanized and their digestive tract was divided into 17 segments for fatty acids analyses. We found that supplementing n-3 fatty acids significantly changed the ratio of n-6/n-3 PUFAs, increased the bioavailability of n-3 PUFAs, and altered fatty acid distribution. In addition, in the n-3 diet group, the absorption of saturated fatty acids (SFAs) along the gut was found to be inhibited, which was confirmed by feeding the mice with a diet containing deuterium-labeled palmitic acid and stearic acid. These results show that a diet rich in n-3 PUFAs can significantly modify the distribution and bioavailability of fatty acids, and particularly, may block the absorption of SFAs in the mouse gastrointestinal (GI) tract.