Avenanthramide supplementation reduces eccentric exercise-induced inflammation in young men and women

Abstract

Background Avenanthramides (AVA) are a group of di-phenolic acids found only in oats and have shown antioxidant and anti-inflammatory effects in vitro and in vivo. Eccentric muscle contraction is intimately involved in rigorous exercise that activates systemic and local inflammatory responses. The objective of the study is to evaluate whether chronic AVA supplementation could attenuate peripheral inflammatory and immunological markers in human subjects in response to an acute bout of downhill running (DR). Methods Eleven male and thirteen female subjects voluntarily participated in this double-blinded, randomized controlled study and were randomly divided into AVA-supplemented (AVA) or control (C) groups. All subjects conducted a DR protocol at − 10% grade with an intensity equivalent to 75% of their maximal heart rate. Blood samples were collected at rest and various time points (0-72 h) after DR (PRE). After an 8-week washout period, participants received two cookies daily containing either 206 mg/kg (AVA) or 0 mg/kg (C) AVA for 8 weeks. Following the oat supplementation regimen, the DR and blood sampling protocols were repeated (POST). Plasma inflammatory and immunological markers were measured using Multiplex immunoassay and muscle soreness was evaluated with pain rating scale. Results DR increased plasma creatine kinase (CK) activity ( P < 0.01) during PRE, but the response was reduced at 24 and 48 h during POST vs. PRE regardless of AVA status ( P < 0.05). Neutrophil respiratory burst (NRB) levels were elevated at 4 and 24 h ( P < 0.05) during PRE but were significantly decreased at 0–48 h during POST vs. PRE ( P < 0.05 or 0.01). Granulocyte-colony stimulating factor (G-CSF), the neutrophil stimulating cytokine, was also increased in response to DR but showed lower levels in AVA compared to C during POST vs. PRE ( P < 0.05). Plasma interleukin-6 (IL-6) content showed an increase at 0 and 4 h during PRE and 0 h during POST ( P < 0.01), whereas during POST there was a trend toward a lower IL-6 level in AVA vs. C ( P = 0.082). Plasma levels of anti-inflammatory agent interleukin-1 receptor antagonist (IL-1Ra) showed an increase at 4 h during PRE, and was significantly elevated in AVA vs. C during POST. Both soluble vascular cell adhesion molecule-1 (sVCAM-1) and monocyte chemoattractant protein-1 (MCP-1) contents increased at 0 and 24 h post DR during PRE as well as POST sessions, however, sVCAM-1 content was lower in AVA vs. C during POST ( P < 0.05) and MCP-1 levels were below resting level at 24, 48 and 72 h during POST ( P < 0.05). DR increased muscle pain at all post-DR time points ( P < 0.01), but the pain level was alleviated by oat supplementation at 48 and 72 h...

The Role of Oat Nutrients in the Immune System: A Narrative Review

“…Avenanthramides are polyphenolics unique to oats and display anti-inflammatory effects. Using an acute eccentric exercise-induced inflammation model, avenanthramide supplementation (20.6 mg/day for 8 weeks) reduced circulatory inflammatory cytokines and inhibited expression of chemokines and cell adhesion molecules in 24 young adults [ 110 ]. Similarly, avenanthramides (9.2 mg/d for 8 weeks) blunted acute eccentric exercise-induced neutrophil respiratory burst in 16 young women.…”

Effects of Dietary Strategies on Exercise-Induced Oxidative Stress: A Narrative Review of Human Studies

“…The majority of currently available studies addressed the effects of phenol-rich foods on exercise-induced oxidative stress, including dark chocolate [ 29 , 30 , 31 ], high-flavanol cocoa drink [ 32 ], green tea [ 33 ], mate tea [ 34 ], New Zealand blueberry smoothie [ 35 ], blueberries [ 36 , 37 ], grape juice [ 38 , 39 ], Montmorency cherry juice [ 40 ], tart cherry juice [ 41 ], oatmeal [ 42 ], avenanthramides (AVA)-rich cookie [ 43 , 44 ], juçara juice [ 45 ], Sanguinello cultivar red orange juice [ 46 ], and purple sweet potato leaves [ 47 ]. Frequently, the effects of dietary strategies on exercise-induced stress are evaluated within short-term [ 29 , 32 , 35 , 36 , 38 , 42 , 45 ], as well as long-term interventions [ 30 , 31 , 33 , 34 , 37 , 39 , 40 , 41 , 43 , 44 , 46 , 47 ]. Across all studies, there is a compelling amount of evidence suggesting that different dietary regimens are viable tools for decreasing exercise-induced oxidative stress.…”

“…In this review, diets with antioxidant effects have demonstrated to reduce inflammatory markers including neutrophil respiratory burst (NRB), interleukin-6 (IL-6), nuclear factor-kappa B (NF-κB), granulocyte-colony stimulating factor (G-CSF), interleukin-1 receptor antagonist (IL-1Ra), soluble vascular cell adhesion molecule-1 (sVCAM-1). In this narrative review, n = 3 studies ([ 43 , 44 , 54 ]) showed decreases in inflammatory markers from the diet interventions.…”

“…Koenig et al, [ 43 ] and Zhang et al, [ 44 ] investigated the eight-week effects of AVA-rich cookies on exercise-induced oxidative stress by detecting the inflammatory markers. Both found that this AVA-rich diet decreased ROS production from the NRB after high intensity downhill training when compared to control group.…”

“…Additionally, plasma IL-6 and NF-κB activity significantly decreased in AVA group versus control group in the study of young women by Koenig et al, [ 43 ]. Zhang et al, [ 44 ] further found that the neutrophil stimulating cytokine G-CSF, IL-1Ra, sVCAM-1 was significantly lower in AVA group compared to the control group after exercise stress. Similar to the study by Zeng et al, [ 42 ], the main antioxidant effects of these two investigations were described as being attributed to AVA components.…”