Dobson, Justin P (2015-01). Effects of Docosahexaenoic Acid Supplementation on Lipids, Lipoproteins and Inflammatory Markers Following Heavy Physical Training in Division I Football Athletes. Doctoral Dissertation.
Thesis
Dietary docosahexaenoic acid (DHA) (22:6 n-3) has been linked to many health benefits in sedentary populations, positively altering lipid profiles and reducing inflammation. The prospective impacts of DHA supplementation in an athletic population during intensive physical training are less clear. The first investigation describes inflammatory responses and the second describes lipid and lipoprotein responses during intensive physical training with DHA supplementation in football athletes. Sixty NCAA Division I football players (20 +- 1.5 years, 187.4 +- 6.1 cm, 105.7 +- 18.9 kg) were randomly assigned to 2 goday^-1 DHA (n=28) or corn-oil placebo (n=32). Blood samples were collected at voluntary summer training (Summer), 30 days after Summer (Pre-camp), and 24 days after Pre-camp (Post-camp). Selected cytokines (multiplex assay), WBC #, percent leukocytes, total cholesterol (TC), triglycerides (TG), LDL, HDL, IDL, and VLDL cholesterol (-C) and lipoprotein particles were analyzed. One sample t-tests (?=0.05) were used to assess differences in percent change of cytokine concentration, leukocyte concentration, lipoprotein concentration, particle numbers, and density at each time point; independent t-tests (?=0.05) were used for differences between groups at Summer. Eotaxin and monocyte chemoattractant protein-1 (MCP-1) elevations were significantly attenuated in the DHA group during preseason camp compared to Placebo (P < 0.05). Regulated on activation, normal T cell expressed and secreted (RANTES) was significantly elevated in both groups (P < 0.05); however, the percent change increase in the Placebo group was 2-fold that of the DHA group. White blood cell counts decreased at Post-camp (P < 0.05) in both groups. Pre-camp percent change TG was significantly (P < 0.05) increased only in the Placebo group. Post-camp percent change TG and HDL particle number in the DHA group was significantly (P < 0.05) reduced. LDL4 number significantly increased in the DHA group (Post-camp, P < 0.05), and the Placebo group decreased in LDL-C (Pre-camp, P < 0.05). Both groups had increased HDL2b-C and HDL2a-C at Pre-camp (P<0.05). Pre-camp LDL3-C and Post-camp LDL4-C increased in the DHA group (P<0.05). RLP-C increased in the Placebo group (Pre-camp, P<0.05). Pre-camp HDL density and Post-camp LDL density decreased in the Placebo group. The DHA group decreased HDL density during preseason, but LDL density remained constant. Summer IDL-C was significantly (P < 0.05) higher in the DHA group. Percent change VLDL number was significantly (P < 0.05) increased during preseason camp. There was no difference in lipoprotein-a and C-reactive protein between groups. TC, HDL-C, and RLP number did not change over time nor differ between groups. Pre-camp homocysteine increased, while Post-camp insulin significantly (P < 0.05) decreased in the DHA group. These investigations further our knowledge of a particular omega-3 fatty acid (DHA) as a potential lipid mediator to mitigate cardiovascular risk, as well as an inflammatory modulator for possible overtraining. Adequate dosage for the anti-inflammatory and lipid profile improving effects of DHA in a sedentary population is still unclear for this particular athletic population.
