Dioum, E. M., Schneider, K. L., Vigerust, D. J., Cox, B. D., . . . Furman, D. (2022). Oats lower age-related systemic chronic inflammation (iAge) in adults at risk for cardiovascular disease. Nutrients, 14(21), 4471. doi:10.3390/nu14214471
Abstract:
Despite being largely preventable, cardiovascular disease (CVD) is still the leading cause of death globally. Recent studies suggest that the immune system, particularly a form of systemic chronic inflammation (SCI), is involved in the mechanisms leading to CVD; thus, targeting SCI may help prevent or delay the onset of CVD. In a recent placebo-controlled randomized clinical trial, an oat product providing 3 g of β-Glucan improved cholesterol low-density lipoprotein (LDL) levels and lowered cardiovascular risk in adults with borderline high cholesterol. Here, we conducted a secondary measurement of the serum samples to test whether the oat product has the potential to reduce SCI and improve other clinical outcomes related to healthy aging. We investigated the effects of the oat product on a novel metric for SCI called Inflammatory Age® (iAge®), derived from the Stanford 1000 Immunomes Project. The iAge® predicts multimorbidity, frailty, immune decline, premature cardiovascular aging, and all-cause mortality on a personalized level. A beneficial effect of the oat product was observed in subjects with elevated levels of iAge® at baseline (>49.6 iAge® years) as early as two weeks post-treatment. The rice control group did not show any significant change in iAge®. Interestingly, the effects of the oat product on iAge® were largely driven by a decrease in the Eotaxin-1 protein, an aging-related chemokine, independent of a person’s gender, body mass index, or chronological age. Thus, we describe a novel anti-SCI role for oats that could have a major impact on functional, preventative, and personalized medicine.
Sang S., Idehen E., Zhao Y., & Chu Y. (2020). Emerging science on whole grain intake and inflammation. Nutrition Reviews, 71(S1), 21-28. doi: 10.1093/nutrit/nuz079
Abstract:
Although the biological mechanisms surrounding the widely reported association between whole grain (WG) consumption and reduced risk of several diseases are not fully understood, there is growing evidence suggesting that inflammation may be an essential mediator in this multifaceted process. It also appears that several mechanisms influence the modulatory actions of WGs on inflammation, including the effect of fiber, phytochemicals, and their microbial-derived metabolites. While some of these effects are direct, others involve gut microbiota, which transform important bioactive substances into more useful metabolites that moderate inflammatory signaling pathways. This review evaluates emerging evidence of the relationship between WGs and their effects on markers of subclinical inflammation, and highlights the role of fiber, unique WG phytochemicals, and gut microbiota on the anti-inflammatory effects of WG intake.
Zhang, T., Zhao, T., Zhang, Y., Liu, T., . . . Ji, L. L. (2020). Avenanthramide supplementation reduces eccentric exercise-induced inflammation in young men and women. Journal of the International Society of Sports Nutrition, 17, 41. doi:10.1186/s12970-020-00368-3
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 during POST regardless of AVA treatment (P < 0.05). Conclusions: Oat AVA supplementation reduced circulatory inflammatory cytokines and inhibited expression of chemokines and cell adhesion molecules induced by DR.
Pavadhgu, P., Bumrungpert, A., Harjani, Y., & Kurilich, A. (2019). Oat porridge consumption alleviates markers of inflammation and oxidative stress in hypercholesterolemic adults. Asia Pacific Journal of Clinical Nutrition, 28(2), 260-265. doi:10.6133/apjcn.201906_28(2).0008
Abstract:
Background and Objectives: Oats contain antioxidant phytochemicals that may help reduce inflammation as well as oxidative stress. In this study we aimed to investigate the effect of oat porridge consumption on inflammatory marker levels and oxidative stress in Thai adults with high blood lipid levels. Methods and Study Design: A randomized crossover study was conducted. Hypercholesterolemic adults were randomly assigned to a 4-week daily consumption of oat or rice porridge. After 4 weeks, they were switched to alternate intervention arms for 4 weeks. At baseline, before and after each intervention period, inflammatory markers including hsCRP, IL-6, IL-8, TNF-α, and MCP-1 and antioxidant status markers including ORAC, FRAP, and MDA of all subjects were measured. Results: Compared to baseline, levels of hsCRP, IL-6, IL-8, and TNF-α were significantly decreased after oat porridge consumption (mean change: -0.6±0.9 mg/L, -26.9±27.6 pg/mL, -56.3±27.6 pg/mL, and - 9.7±11.6 pg/mL, p＜0.05 for all, respectively). In addition, consumption of oat porridge also increased antioxidant capacity; ORAC and FRAP levels (mean change: 2.7±1.0 μmol of Trolox/L and 2.4±0.8 μmol of Fe^(2+)/L, p＜0.001, respectively). However, MCP-1 and MDA levels were not affected. Consumption of rice porridge did not lead to significant changes in these measures. Conclusions: Daily consumption of 70 grams oat porridge containing 3 grams β-glucan for 4 weeks may help reduce markers of inflammation and oxidation in hypercholesterolemic adults. Therefore, oat may be an appropriate dietary recommendation for individuals with hypercholesterolemia.
Fu, J., Zhu, Y., Yerke, A., Wise, M. L., . . . Sang, S. (2015). Oat avenanthramides induce heme oxygenase-1 expression via Nrf2-mediated signaling in HK-2 cells. Molecular Nutrition and Food Research, 59(12), 2471-2479. doi:10.1002/mnfr.201500250
Abstract:
Scope Numerous studies have shown that avenanthramides (AVAs), unique compounds found in oats, are strong antioxidants, though the mechanism of action remains unclear. Here, we investigated whether AVAs affect heme oxygenase-1 (HO-1) expression through the activation of Nrf2 translocation. Methods and results We investigated the effects AVA 2c, 2f, and 2p on HK-2 cells, and found that AVAs could significantly increase HO-1 expression in both a dose- and time-dependent manner. Furthermore, we found that AVA-induced HO-1 expression is mediated by Nrf2 translocation. The addition of N-acetylcysteine (NAC), but not specific inhibitors of p38 (SB202190), PI3K (LY294002), and MEK1 (PD098059) attenuated AVA-induced HO-1 expression, demonstrating an important role for reactive oxygen species, but not PI3K or MAPK activation, in activating the HO-1 pathway. Moreover, hydrogenation of the double bond of the functional α,β-unsaturated carbonyl group of AVAs eliminated their effects on HO-1 expression, suggesting that this group is crucial for the antioxidant activity of AVAs. Conclusion Our results suggest a novel mechanism whereby AVAs exert an antioxidant function on human health. Further investigation of these markers in human is warranted to explore the beneficial health effects of whole grain oat intake.
Koenig, R., Dickman, J. R., Kang, C., Zhang, T., . . . Ji, L. L. (2014). Avenanthramide supplementation attenuates exercise-induced inflammation in postmenopausal women. Nutrition Journal, 13, 21. doi:10.1186/1475-2891-13-21
Abstract:
During aging, chronic systemic inflammation increases in prevalence and antioxidant balance shifts in favor of oxidant generation. Avenanthramide (AVA) is a group of oat phenolics that have shown anti-inflammatory and antioxidant capability. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation after a bout of downhill walking (DW) in postmenopausal women. Women at age of 50–80 years (N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA or 0.4 mg AVA (control, C) each day for 8 weeks. Before and after the dietary regimen, each group of subjects walked downhill on a treadmill (−9% grade) for 4 bouts of 15 minutes at a speed of 4.0 km/h with 5 minutes rest between sessions. Blood samples were collected at rest, 24 h post-DW, and 48 h post-DW pre- and post-supplementation. Both DW sessions increased plasma creatine kinase activity (P < 0.05). Before supplementation, in vitro neutrophil respiratory burst (NRB) activity was increased at 24 h post-DW (P < 0.05) and C-reactive protein (CRP) was increased 48 h post-DW (P < 0.05). AVA supplementation decreased DW-induced NRB at 24 h (P < 0.05) and CRP level 48 h (P < 0.05). Plasma interleukin (IL)-1β concentration and mononuclear cell nuclear factor (NF) κB binding were suppressed at rest and during post-DW period in AVA but not C group (P < 0.05). Plasma total antioxidant capacity (P < 0.05) and erythrocyte superoxide dismutase activity were increased in AVA vs. C (P < 0.05), whereas glutathione redox status was elevated 48 h post-DW but not affected by AVA. Thus, chronic AVA supplementation decreased systemic and DW-induced inflammation and increased blood-borne antioxidant defense in postmenopausal women.
Yang, J., Ou, B., Wise, M. L., & Chu, Y. (2014). In vitro total antioxidant capacity and anti-inflammatory activity of three common oat-derived avenanthramides. Food Chemistry, 160, 338-345. doi:10.1016/j.foodchem.2014.03.059
Abstract:
To better understand mechanisms underlying the health benefits of oats, the free radical scavenging capacities of oat avenanthramides 2c, 2f, and 2p and their ability to inhibit NF-κB activation were evaluated. The antioxidant capacities of 2c, 2f, and 2p against peroxyl radicals, hydroxyl radicals, superoxide anion, singlet oxygen, and peroxynitrite were determined by using ORAC, HORAC, SORAC, SOAC, and NORAC assays, respectively. The total antioxidant capacity of 2c was approximately 1.5-fold those of 2f and 2p. Total antioxidant capacity was primarily attributable to SORAC and ORAC for 2c (>77%, p < 0.05), and to ORAC and SOAC for 2f. ORAC accounted for approximately 32% of total antioxidant capacity in 2p. EC50 values for inhibiting TNF-α-induced NF-κB activation in C2C12 cells were 64.3, 29.3, and 9.10 μM for 2c, 2f, and 2p, respectively. Differences in antioxidant capacities and ability to inhibit NF-κB among the avenanthramides could be ascribed to structural variations.
Chu, Y. F., Wise, M. L., Gulvady, A. A., Chang, T., . . . O'Shea, M. (2013). In vitro antioxidant capacity and anti-inflammatory activity of seven common oats. Food Chemistry, 139(1-4), 426-431. doi:10.1016/j.foodchem.2013.01.104
Abstract:
Oats are gaining increasing scientific and public interest for their purported antioxidant-associated health benefits. Most reported studies focused on specific oat extracts or particular oat components, such as β-glucans, tocols (vitamin E), or avenanthramides. Studies on whole oats with respect to antioxidant and anti-inflammatory activities are still lacking. Here the antioxidant and anti-inflammatory activities from whole oat groats of seven common varieties were evaluated. All oat varieties had very similar oxygen radical absorption capacity compared with other whole grains. In an anti-inflammatory assay, oat variety CDC Dancer inhibited tumor necrosis factor-α induced nuclear factor-kappa B activation by 27.5% at 2 mg/ml, whereas variety Deiter showed 13.7% inhibition at a comparable dose. Avenanthramide levels did not correlate with the observed antioxidant and anti-inflammatory activities. Further investigations are needed to pinpoint the specific antioxidant and anti-inflammatory compounds, and potential synergistic and/or matrix effects that may help explain the mechanisms of oat’s anti-inflammatory actions.