Insights & Discussion
Consumption of oat β-glucan may lower cholesterol and risk of cardiovascular disease by altering gut bacteria and their effects on bile acid and cholesterol metabolism.
The research paper focused on studying the impact of oat β-glucan on cholesterol levels and cardiovascular disease risk. The methodology revolved around examining how consumption of oat β-glucan might change the gut microbiota, particularly bacterial species that influence bile acid metabolism and the production of short chain fatty acids. These factors are crucial regulators of cholesterol homeostasis in the host body. The research thus looked into the repercussions on bile acid metabolism, reverse cholesterol transport, short-chain fatty acid production, bacterial metabolism of cholesterol, and microbe-host signaling.
The researchers found that oat β-glucan appears to have a significant effect on both the host's cholesterol levels and the composition and functionality of their gut microbiota, which in turn impacts bile acid metabolism and cholesterol homeostasis. It creates a potentially beneficial scenario where intestinal cholesterol may be removed for excretion. The results suggest that the benefits attributed to oat β-glucan are multifaceted and likely involve the regulation of complex interactions between microbes and the host at the level of the gastrointestinal interface. These novel insights demonstrate an interesting relationship between diet, gut microbiota, and host cholesterol metabolism.
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Oat supplementation interventions can improve cardiovascular health markers among adults, regardless of their diet or metabolic conditions.
2022 European Journal of Nutrition Effect of oat supplementation interventions on cardiovascular disease risk markers: a systematic review and meta-analysis of randomized controlled trials Llanaj E, Dejanovic GM, Valido E, Bano A, Gamba M, Kastrati L, et al.
Meta-Analysis Cardiovascular Disease Cholesterol Oats
The methodology involved analyzing various randomized clinical trials that tested how oats, or extracts rich in oat beta-glucan and avenanthramides affected markers of cardiovascular disease risk. The sample population was predominantly subjects with high cholesterol, obesity, and mild metabolic disturbances. Interventions were compared to control arms without oats.
In the discussion on results, it was found that subjects receiving the oat supplementation had improved health metrics such as total cholesterol, LDL cholesterol, glucose levels, body mass index, weight, and waist circumference. However, when the oat supplementation was compared to heterogeneous interventions, like wheat, eggs, rice, etc., reductions in the levels of glycated haemoglobin, diastolic blood pressure, HDL cholesterol, and apolipoprotein B were also seen. Despite these promising results, there were some concerns around the bias risk associated with the majority of included randomized clinical trials.
Fresh Hass avocados have been found to reduce cardiovascular disease risk, assist weight loss, improve cognitive function, and promote colonic microbiota health.
2021 Nutrients A Comprehensive Review of Hass Avocado Clinical Trials, Observational Studies, and Biological Mechanisms Dreher ML, Cheng FW, Ford NA
Review Article Avocado Cardiovascular Disease Gut Microbiota
The methodology used in this comprehensive review entailed conducting 19 clinical trials, five observational studies, and examination of several biological mechanisms. These focused on understanding and identifying the primary health effects of Hass avocados in different population groups such as healthy overweight or obese adults, older normal-weight adults, and overweight or obese women. The effects were thoroughly measured in terms of cardiovascular health, body weight, cognitive function, and colonic microbiota health.
The primary health effects of Hass avocados were then linked to its unique nutritional properties - the unsaturated to saturated fat ratio, the presence of multifunctional prebiotic and viscous fiber, its low energy density, and the increase in carotenoid absorption facilitated by its oleic acid and water emulsion, particularly when combined with low-fat fruits and vegetables.
The results indicated significant positive effects from consuming Hass avocados, especially when incorporated into a healthy dietary plan like the Mediterranean diet. Consumption of avocados was found to lead to reduced cardiovascular disease risk in healthy overweight or obese adults, primarily by undesirable cholesterol profiles and promoting vascular health. For overweight or obese women, it helped in weight reduction and lessened visceral fat tissue. The consumption of avocados improved cognitive function in both older normal-weight adults and young to middle age overweight adults, particularly their executive function. It was also found to enhance colonic microbiota health in overweight or obese individuals by fostering healthier microflora and fecal metabolites.
Enriching a regular diet with oat β-glucan can improve glycemic control, augment feelings of fullness, and positively modulate gut microbiota in individuals with type-2 diabetes.
2021 Journal of Functional Foods Effect of dietary supplementation with oat β-glucan for 3 months in subjects with type 2 diabetes: A randomized, double-blind, controlled clinical trial Pino JL, Mujica V, Arredondo M
Randomised Controlled Trial Blood Sugar Gut Microbiota HbA1C
The research involved 37 subjects with type-2 diabetes, who were required to consume either oat β-glucan or microcrystalline cellulose as a control dietary supplement each day for a period of 12 weeks. The parameters assessed throughout the study included fasting glucose, insulin, a variety of hormones and peptides regulating appetite (like ghrelin, leptin, GLP-1, PYY), caloric intake, and the profile of their intestinal microbiota.
The results indicated a decrease in HbA1c, insulin, C-peptide levels, as well as certain bacterial populations (Lactobacillus spp, and Butyrate-producing bacteria) in subjects who consumed β-glucan. Significant differences were observed in levels of certain hormones, namely leptin, GLP-1, and PYY, between the two groups. The intake of oat β-glucan emerged as a potential strategy to manage type-2 diabetes, by improving glycemic control, enhancing feelings of satiety, and fostering a healthier gut microbiota profile.
Oats improve gastrointestinal health, reduce cholesterol, and regulate satiety, with effects on the gut microbiome constituting an appealing new research area.
2019 Nutrition Reviews Effects of oats on gastrointestinal health as assessed by in vitro, animal, and human studies Korczak R, Kocher M, Swanson KS
Review Article Cholesterol Digestive Health Gut Microbiota
The researchers undertook a comprehensive literature review using predefined search criteria and keywords related to gastrointestinal health outcomes in the PubMed database. They sought to explore the impact of oats on gastrointestinal health in humans, with the intent to identify both human and animal studies, as well as in vitro studies, that met their specific inclusion criteria. They extracted data from eight human studies, nineteen animal trials, and five in vitro studies for this synthesis.
The results underscore that oats, due to their unique composition of bioactive compounds, lipids, and β-glucan, have beneficial effects on gastrointestinal health. The human studies showed consistent beneficial outcomes, with complementary evidence from animal and in vitro studies. The degree of effect, however, appeared to vary depending on the type of oats and dosage used. For instance, oat types providing between 2.5 to 2.9 grams of β-glucan a day were found to decrease fecal pH and alter fecal bacteria, while 40 to 100 grams per day of oat bran was shown to boost bacterial mass and short-chain fatty acids in human feces. The researchers note that different study designs, methodologies, and types of oats used make comparing results challenging.