title: Red blood cell PUFAs reflect the phospholipid PUFA composition of major organs.
abstract: Numerous clinical trials examining the use of omega-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) on various health outcomes have been conducted, and fish oil remains one of the most widely used nutritional supplements. More recently, studies have begun to utilize the omega-3 index, defined as the sum of EPA+DHA in red blood cells (RBCs), as both a biomarker of n-3 LCPUFA exposure and a potential risk factor for coronary heart disease (CHD). Considerably less research evaluates whether RBC phospholipid fatty acids reflect the phospholipid fatty acid composition of other tissues across increasing intakes of n-3 LCPUFAs. We fed mice diets containing increasing amounts of EPA+DHA, equivalent to current recommendations by the American Heart Association on a percent of energy basis, and analyzed the phospholipid fatty acid composition of various tissues in relation to RBCs. We observed that RBCs, heart, muscle, spleen, lung, and adipose tissues all respond to dietary supplementation with EPA+DHA with increasing n-3 LCPUFA and decreasing n-6 LCPUFA levels. Furthermore, the n-3 LCPUFA profiles of all measured tissues had strong (r>0.7) and significant (p<0.001) correlations to RBCs. Interestingly, we also observed changes in saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) levels across various tissues in response to increased EPA+DHA intakes despite there being no change in dietary SFA and MUFA. Specifically, there were increases in RBC SFA and spleen MUFA and decreases in heart MUFA. These demonstrate that the RBC, including the omega-3 index, may serve as a marker for the relative levels of n-3 and n-6 LCPUFAs in phospholipids of certain tissues.
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, 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
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, United States.
authors.forename: Eric A
authors.initials: EA
authors.lastname: Gurzell
authors.affiliation: Department of Food Science and Human Nutrition, Michigan State University, United States.
authors.forename: Emily A
authors.initials: EA
authors.lastname: Davidson
authors.affiliation: Sanford School of Medicine, The University of South Dakota, and OmegaQuant, LLC, Sioux Falls, SD, United States.
authors.forename: William S
authors.initials: WS
authors.lastname: Harris
mesh_terms: D000273:Adipose Tissue / Q000737:chemistry; D000818:Animals; D004042:Dietary Fats, Unsaturated / Q000008:administration & dosage / Q000097:blood; D004912:Erythrocytes / Q000737:chemistry*; D005227:Fatty Acids / Q000032:analysis / Q000097:blood / Q000378:metabolism; D005229:Fatty Acids, Monounsaturated / Q000032:analysis / Q000097:blood / Q000378:metabolism; D015525:Fatty Acids, Omega-3 / Q000008:administration & dosage* / Q000097:blood; D005231:Fatty Acids, Unsaturated / Q000097:blood* / Q000378:metabolism*; D008168:Lung / Q000737:chemistry; D051379:Mice; D009132:Muscles / Q000737:chemistry; D009206:Myocardium / Q000737:chemistry; D010743:Phospholipids / Q000097:blood* / Q000378:metabolism*; D013154:Spleen / Q000737:chemistry; D014018:Tissue Distribution
chemical_list: D004042:Dietary Fats, Unsaturated; D005227:Fatty Acids; D005229:Fatty Acids, Monounsaturated; D015525:Fatty Acids, Omega-3; D005231:Fatty Acids, Unsaturated; D010743:Phospholipids
keywords: Adipose; Biomarker; Fish oil; Heart; Lung; Muscle; Omega-3 index; PUFA; Phospholipid; RBC