Title

Echinacea-induced erythropoiesis: Effects on oxygen transport and exercise performance

Date of Award

2006

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Human Performance and Recreation

First Advisor

Michael Webster

Advisor Department

Human Performance and Recreation

Abstract

Echinacea is an herbal supplement primarily utilized as an immunostimulant. Evidence from animal and cell culture models indicates that Echinacea may increase oxygen transport capacity. The purposes of this investigation were (1) to determine the effects of four-weeks of oral Echinacea supplementation on erythropoietin, red blood cell count, running economy, and VO 2 max , (2) to determine whether oral Echinacea supplementation results in alterations in erythroid growth factors and markers of erythropoietic status. Twenty-four males (aged 24.9 ± 4.2 yr, height 178.9 ± 7.9 cm, weight 87.9 ± 14.6 kg, body fat 19.3 ± 6.5 %) were supplemented with either 8000 mg·d -1 of Echinacea (ECH) (n=12) or a placebo (PLA) (n=12). Blood samples were collected prior to and every 7-d during supplementation and analyzed for erythropoietin, red blood cells, hematocrit, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin content, prostaglandin E 2 , ferritin, erythropoietin, interleukin-3, and granulocyte-macrophage colony stimulating factor. Maximal graded exercise tests were administered to measure VO 2 max , running economy, and heart-rate responses. Significant between groups differences were determined from ANOVA with significance set at P ≤ 0.05. Erythropoietin increased significantly in ECH at days 7 (15.75 ± 0.64 vs. 10.01 ± 0.73 mU·mL -1 ), 14 (18.88 ± 0.71 vs. 11.02 ± 0.69 mU·mL -1 ), and 21 (16.06 ± 0.55 vs. 9.20 0.55 mU·mL -1 ). Interleukin-3 was significantly greater in ECH at days 14 (460.91 ± 21.01 vs. 347.64 ± 13.46 pg·mL -1 ) and 21 (483.28 ± 44.09vs. 32.22 ± 26.58 pg·mL -1 ). VO 2 max increased significantly in ECH (1.47 ± 1.28 vs. -0.13 ± 0.52 %). Running economy improved significantly in ECH as indicated by a decrease in submaximal VO 2 during the first 2 stages of the graded exercise test (Stage 1: -1.50 ± 1.21 vs. 0.60 ± 1.95; Stage 2: -1.67 ± 1.43 vs. 0.01 ± 1.03 %; ECH and PLA, respectively). These data suggest that Echinacea supplementation results in significant increases in erythropoietin, and interleukin-3, VO 2max , and running economy, but did not alter measures of erythropoietic status.