Key Laboratory of Environmental Medicine and Engineering of Ministry of Education, and Department of Nutrition and Food Hygiene, School of Public Health, Southeast University, Nanjing 210009, PR China.
Chinese Nutrition Center for Education, Beijing 100101, PR China.
Food Res Int. 2022 Oct;160:111701. doi: 10.1016/j.foodres.2022.111701. Epub 2022 Jul 26.
Cardiovascular diseases have been the leading cause of death worldwide for decades. Some animal studies have indicated that oatmeal could improve gut microbiota and cardiometabolic risk markers. However, vivo evidence remained limited, especially in individuals with mild hypercholesterolemia. Our purpose was to explore the beneficial effects of oatmeal on serum lipids, oxidative stress and inflammation levels, and their correlations with gut microbiota and short-chain fatty acids (SCFAs) in mildly hypercholesterolemic individuals. The study was a randomized, single-blind, placebo-controlled trial. A total of 62 qualified participants were randomly divided into control group and oatmeal group with a 45-day follow-up. 16S rDNA and Gas-Chromatography Mass Spectrometry were employed respectively to measure the changes in gut microbiota and SCFAs at the start and the end of the intervention period. Cardiometabolic risk markers were assayed via commercial kits. The results suggested that oatmeal could significantly decrease serum total cholesterol (TC) (-8.59 %, p = 0.013), low density lipoprotein cholesterol (LDL-c) (-12.97 %, p = 0.004) and non-high density lipoprotein cholesterol (non-HDL-c) (-10.98 %, p = 0.040) level. In terms of oxidative stress, oatmeal significantly increased serum total antioxidant capacity (T-AOC) (21.98 %, p < 0.001), superoxide dismutase (SOD) (15.53 %, p = 0.044) levels and decreased concentration of malondialdehyde (MDA) (-19.11 %, p = 0.033) compared with control group. While no significant effect was observed in inflammatory factors. SCFAs results indicated that oatmeal could significantly increase serum acetic acid, propionic acid and valeric acid. The results of 16S rDNA showed that there was a significant difference in the alteration of β-diversity between groups throughout the whole trial. Oatmeal resulted in the increases of Akkermansia, Dialister, Faecalibacterium, Barnesiella, Agathobacter, Lactobacillus and the decrease of Ruminococcaceae-MK4A214-group. Correlation analysis further suggested that the lipids regulation effect of oatmeal may be mainly mediated by Lactobacillus and Dialister, as well as some SCFAs (e.g., acetic acid and propionic acid), while Barnesiella and Akkermansia may play a crucial role in ameliorating oxidative stress level. In conclusion, despite of its small sample size, the present study is the first clinical trial performed in Chinese individuals with mild hypercholesterolemia to explore the effects of oatmeal on serum lipids, oxidative stress, inflammation levels, and gut microbiota. The results demonstrated that oatmeal could induce some beneficial changes in serum lipids, oxidative stress, gut microbiota composition and SCFAs. Correlation analysis further extended our understanding of the role of gut microbiota and SCFAs in improving cardiometabolic risk markers.
几十年来，心血管疾病一直是全球范围内的主要死亡原因。一些动物研究表明，燕麦片可以改善肠道微生物群和心脏代谢风险标志物。然而，体内证据仍然有限，特别是在轻度高胆固醇血症患者中。我们的目的是探讨燕麦片对血清脂质、氧化应激和炎症水平的有益影响，以及它们与肠道微生物群和短链脂肪酸 (SCFAs) 的相关性，在轻度高胆固醇血症患者中。该研究是一项随机、单盲、安慰剂对照试验。共有 62 名合格参与者被随机分为对照组和燕麦组，随访 45 天。16S rDNA 和气相色谱-质谱法分别用于测量干预前后肠道微生物群和 SCFAs 的变化。通过商业试剂盒测定心脏代谢风险标志物。结果表明，燕麦片可显著降低血清总胆固醇（TC）（-8.59%，p=0.013）、低密度脂蛋白胆固醇（LDL-c）（-12.97%，p=0.004）和非高密度脂蛋白胆固醇（非-HDL-c）（-10.98%，p=0.040）水平。在氧化应激方面，燕麦片可显著增加血清总抗氧化能力（T-AOC）（21.98%，p<0.001）、超氧化物歧化酶（SOD）（15.53%，p=0.044）水平，并降低丙二醛（MDA）浓度（-19.11%，p=0.033）与对照组相比。而炎症因子则无明显变化。SCFAs 结果表明，燕麦片可显著增加血清乙酸、丙酸和缬草酸。16S rDNA 的结果表明，整个试验过程中两组之间β多样性的变化存在显著差异。燕麦片导致阿克曼氏菌、双岐杆菌、粪杆菌、巴氏杆菌、阿加特杆菌、乳杆菌增加，罗氏菌科-MK4A214 组减少。相关性分析进一步表明，燕麦片的脂质调节作用可能主要通过乳杆菌和双岐杆菌以及一些 SCFAs（如乙酸和丙酸）介导，而巴氏杆菌和阿克曼氏菌可能在改善氧化应激水平方面发挥关键作用。总之，尽管样本量较小，但本研究是首次在中国轻度高胆固醇血症患者中进行的临床试验，旨在探讨燕麦片对血清脂质、氧化应激、炎症水平和肠道微生物群的影响。结果表明，燕麦片可诱导血清脂质、氧化应激、肠道微生物群组成和 SCFAs 发生有益变化。相关性分析进一步扩展了我们对肠道微生物群和 SCFAs 改善心脏代谢风险标志物作用的认识。
