Oat and oatmeal studies

Wolever TMS, Jenkins AL, Prudence K, Johnson J, Duss R, Chu Y, Steinert RE. Effect of adding oat bran to instant oatmeal on glycaemic response in humans - a study to establish the minimum effective dose of oat β-glucan. Food Funct. 2018 Mar 1;9(3):1692-1700. doi: 10.1039/c7fo01768e. Epub 2018 Feb 26. PMID: 29480316.

Abstract. Reducing the glycaemic response to carbohydrate-containing foods may have desirable physiological effects for many people. Here, we aimed to determine the minimum amount of oat β-glucan from oat-bran which, when added to instant-oatmeal, would reduce the glycaemic response by 20% compared to a β-glucan-free cereal. Therefore, the glycaemic responses elicited by one serving (27 g) instant-oatmeal plus 247 g 2% milk (IO, 28 g available-carbohydrate, 1.2 g β-glucan) or IO plus 0.2, 0.4, 0.8 or 1.6 g oat β-glucan (OBG) from oat-bran, or an available-carbohydrate matched portion of cream of rice (CR) plus milk were measured over 2 h in n = 40 subjects using a randomized, cross-over design. The primary endpoint was incremental area under the curve (iAUC). The secondary endpoint was glucose peak-rise. The results showed that grams OBG consumed were significantly correlated with mean iAUC (p = 0.009) and with mean glucose peak-rise (p = 0.002). Each gram of OBG reduced iAUC by 7% and peak-rise by 15%. Thus, to achieve a ≥20% reduction in iAUC relative to CR, 1.6 g OBG had to be added to IO (74 ± 7 vs. 93 ± 6 mmol min L-1, p < 0.05), but, to achieve a 20% reduction in peak-rise, only 0.4 g OBG was required (2.00 ± 0.1 vs. 2.40 ± 0.1 mmol, p < 0.05). We conclude that adding OBG to IO flattened postprandial glycaemic responses in a dose-dependent fashion; 1.6 g OBG was required to reduce iAUC by ≥20% versus CR, but a 20% reduction in peak-rise required only 0.4 g. The greater effect of OGB on peak-rise than iAUC presumably reflects the way viscous dietary fibres modulate glucose absorption kinetics.

Kim SH, Kim KJ, Kang HJ, Son YJ, Choi SW, Lee MJ. The Dual Role of Oat Bran Water Extract in Bone Homeostasis Through the Regulation of Osteoclastogenesis and Osteoblast Differentiation. Molecules. 2018 Nov 28;23(12):3119. doi: 10.3390/molecules23123119. 

Abstract. The number of patients with bone metabolic disorders including osteoporosis is increasing worldwide. These disorders often facilitate bone fractures, which seriously impact the patient's quality of life and could lead to further health complications. Bone homeostasis is tightly regulated to balance bone resorption and formation. However, many anti-osteoporotic agents are broadly categorized as either bone forming or anti-resorptive, and their therapeutic use is often limited due to unwanted side effects. Therefore, safe and effective therapeutic agents are needed for osteoporosis. This study aims to clarify the bone protecting effects of oat bran water extract (OBWE) and its mode of action. OBWE inhibited RANKL (receptor activator of nuclear factor-κB ligand)-induced osteoclast differentiation by blocking c-Fos/NFATc1 through the alteration of I-κB. Furthermore, we found that OBWE enhanced BMP-2-stimulated osteoblast differentiation by the induction of Runx2 via Smad signaling molecules. In addition, the anti-osteoporotic activity of OBWE was also evaluated using an in vivo model. OBWE significantly restored ovariectomy-induced bone loss. These in vitro and in vivo results showed that OBWE has the potential to prevent and treat bone metabolic disorders including osteoporosis.

Wu W, Tang Y, Yang J, Idehen E, Sang S. Avenanthramide Aglycones and Glucosides in Oat Bran: Chemical Profile, Levels in Commercial Oat Products, and Cytotoxicity to Human Colon Cancer Cells. J Agric Food Chem. 2018 Aug 1;66(30):8005-8014. doi: 10.1021/acs.jafc.8b02767. 

Abstract. Avenanthramides (AVAs), unique phytochemicals in oat, have attracted an increasing amount of attention due to their outstanding health benefits. However, the chemical profile and the levels of AVAs in commercial oat products as well as their health benefits have not been examined in detail. In the present study, a total of 29 AVA aglycones and AVA glucosides were identified and characterized from oat bran using NMR (1D and 2D NMR) and LC-MS techniques. Among them, 17 novel AVA glucosides were reported in oat bran for the first time. The most abundant AVA glucoside, 2c-3'- O-glc, had a similar growth inhibitory activity with the major AVA, 2c, against HCT-116 and HT-29 human colon cancer cells, indicating glucosylation does not affect the growth inhibitory effects of AVAs. Furthermore, the levels of all individual AVAs in 13 commercial oat products were analyzed using HPLC-MS/MS. The total AVAs contents in various oat products ranged from 9.22 to 61.77 mg/kg (fresh weight).

Ban Y, Qiu J, Ren C, Li Z. Effects of different cooking methods of oatmeal on preventing the diet-induced increase of cholesterol level in hypercholesterolemic rats. Lipids Health Dis. 2015 Oct 24;14:135. doi: 10.1186/s12944-015-0138-7. PMID: 26498197; PMCID: PMC4619352.

Abstract. Background: The aim of present study is to investigate the influences of brewing and boiling on hypocholesterolemic effect of oatmeal in rats fed with a hypercholesterolemic diet.....Conclusion: These results indicated that the capability of boiled oatmeal in improving cholesterol metabolism is better than that of brewed oatmeal, which is mainly attributed to its higher soluble β-glucan content and apparent viscosity.

Leão LSCS, Aquino LA, Dias JF, Koifman RJ. Addition of oat bran reduces HDL-C and does not potentialize effect of a low-calorie diet on remission of metabolic syndrome: A pragmatic, randomized, controlled, open-label nutritional trial. Nutrition. 2019 Sep;65:126-130. doi: 10.1016/j.nut.2019.03.007. Epub 2019 Mar 23. PMID: 31082790.

Chakraborty P, Witt T, Harris D, Ashton J, Stokes JR, Smyth HE. Texture and mouthfeel perceptions of a model beverage system containing soluble and insoluble oat bran fibres. Food Res Int. 2019 Jun;120:62-72. doi: 10.1016/j.foodres.2019.01.070.

Esfandi R, Willmore WG, Tsopmo A. Peptidomic analysis of hydrolyzed oat bran proteins, and their in vitro antioxidant and metal chelating properties. Food Chem. 2019 May 1;279:49-57. doi: 10.1016/j.foodchem.2018.11.110. 

Jane M, McKay J, Pal S. Effects of daily consumption of psyllium, oat bran and polyGlycopleX on obesity-related disease risk factors: A critical review. Nutrition. 2019 Jan;57:84-91. doi: 10.1016/j.nut.2018.05.036.