title: Is the omega-3 index a valid marker of intestinal membrane phospholipid EPA+DHA content?
abstract: Despite numerous studies investigating n-3 long chain polyunsaturated fatty acid (LCPUFA) supplementation and inflammatory bowel diseases (IBD), the extent to which dietary n-3 LCPUFAs incorporate in gastrointestinal (GI) tissues and correlate with red blood cell (RBC) n-3 LCPUFA content is unknown. In this study, mice were fed three diets with increasing percent of energy (%en) derived from eicosapentaenoic acid (EPA)+docosahexaenoic acid (DHA). Dietary levels reflected recommended intakes of fish/fish oil by the American Heart Association. We analyzed the FA composition of phospholipids extracted from RBCs, plasma, and GI tissues. We observed that the 0.1%en EPA+DHA diet was sufficient to significantly increase the omega-3 index (RBC EPA+DHA) after 5 week feeding. The baseline EPA levels were 0.2-0.6% across all tissues increasing to 1.6-4.3% in the highest EPA+DHA diet; these changes resulted in absolute increases of 1.4-3.9% EPA across tissues. The baseline DHA levels were 2.2-5.9% across all tissues increasing to 5.8-10.5% in the highest EPA+DHA diet; these changes resulted in absolute increases of 3.2-5.7% DHA across tissues. These increases in EPA and DHA across all tissues resulted in strong (r>0.91) and significant (P<0.001) linear correlations between the omega-3 index and plasma/GI tissue EPA+DHA content, suggesting that the omega-3 index reflects the relative amounts of EPA+DHA in GI tissues. These data demonstrate that the GI tissues are highly responsive to dietary LCPUFA supplementation and that the omega-3 index can serve as a valid biomarker for assessing dietary EPA+DHA incorporation into GI tissues.
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, MI, United States.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Gurzell
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, MI, United States.
authors.forename: Jason A
authors.initials: JA
authors.lastname: Wiesinger
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, MI, United States.
authors.forename: Christina
authors.initials: C
authors.lastname: Morkam
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, MI, United States.
authors.forename: Sophia
authors.initials: S
authors.lastname: Hemmrich
authors.affiliation: Sanford School of Medicine, The University of South Dakota, Sioux Falls, SD (WSH), United States.
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, MI, United States; College of Osteopathic Medicine, East Lansing, MI, United States. Electronic address: imigjeni@msu.edu.
authors.forename: Jenifer I
authors.initials: JI
authors.lastname: Fenton
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism / Q000473:pathology; D004041:Dietary Fats / Q000494:pharmacology*; D004281:Docosahexaenoic Acids / Q000378:metabolism* / Q000494:pharmacology; D015118:Eicosapentaenoic Acid / Q000378:metabolism / Q000494:pharmacology; D015212:Inflammatory Bowel Diseases / Q000378:metabolism* / Q000473:pathology; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D018345:Mice, Knockout
chemical_list: D004041:Dietary Fats; D004281:Docosahexaenoic Acids; D015118:Eicosapentaenoic Acid
keywords: Biomarker; Colon; Fatty acids; Intestine; Omega-3; Red blood cell