Insights & Discussion
Oats improve gastrointestinal health, reduce cholesterol, and regulate satiety, with effects on the gut microbiome constituting an appealing new research area.
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.
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Fresh and dried ginger displays key botanical, phytochemical and ethnopharmacological differences, which are fundamental for their specific clinical uses in treating gastrointestinal issues.
2022 The American Journal of Chinese Medicine Zingiber officinale: A Systematic Review of Botany, Phytochemistry and Pharmacology of Gut Microbiota-Related Gastrointestinal Benefits Lai W, Yang S, Lin X, Zhang X, Huang Y, Zhou J, et al.
Systematic Review Ginger Gut Microbiota
The methodology used in the research involved a retrospective comparison between Sheng Jiang (SJ, meaning fresh ginger) and Gan Jiang (GJ, meaning dried ginger), two traditional Chinese herbs. The comparison was undertaken specifically considering aspects of botany, phytochemistry, and ethnopharmacology. The research also delved into exploring the traditionally attributed use of ginger, in both its fresh and dried forms, for the treatment of gastrointestinal disorders, and its relationship with human gut microbiota - an aspect that hasn't been considered extensively previously.
The results displayed notable differences between fresh and dried ginger in terms of botany, phytochemical, and ethnopharmacological properties. Fresh and dried ginger are cultivated differently and display distinct physical appearances. This research proposed that these differences lay the foundation for how these two forms of ginger are applied clinically. Furthermore, discussing the pharmacology of gut microbiota-related gastrointestinal benefits, it is suggested that fresh and dried ginger could present innovative and potent avenues for preventing and treating gastrointestinal disorders.
Two French natural mineral waters (NMW1 and NMW2) show anti-inflammatory effects and can reduce intestinal inflammation in mice with induced colitis.
2021 International Journal of Molecular Sciences Beneficial Effects of Natural Mineral Waters on Intestinal Inflammation and the Mucosa-Associated Microbiota Barnich N, Rodrigues M, Sauvanet P, Chevarin C, Denis S, Le Goff O, et al.
Experimental Study Colitis Gut Microbiota Intestinal Inflammation
The study investigated the anti-inflammatory effects of two French natural mineral waters (NMWs) - NMW1 (rich in calcium, magnesium, sodium, carbon, and iron) and NMW2 (mainly bicarbonate) - on intestinal inflammation. Intestinal epithelial cells were stimulated with heat-inactivated Escherichia coli or hydrogen peroxide and then treated with NMWs. Additionally, moderate colitis was induced in Balbc/J mice using 1% dextran sulfate sodium. These mice were then given either NMW1, NMW2, or control water. The study assessed general symptoms, histological features of colitis, fecal lipocalin-2 levels, pro-inflammatory KC cytokine levels, and the global mucosa-associated microbiota.
Both NMW1 and NMW2 showed anti-inflammatory effects in treated intestinal cells. In the colitis-induced mice, NMW1 notably reduced inflammation, evidenced by lower disease activity scores, reduced fecal lipocalin-2, decreased release of pro-inflammatory KC cytokines, and smaller intestinal epithelial lesions. NMW1 also helped in maintaining the normal state of mucosa-associated microbiota. These findings suggest the potential of these NMWs in managing inflammatory bowel disease through modulating gut microbiota.
Omega-3 fatty acids found in selected fish oils, particularly smoked eel, effectively managed dyslipidemia and reduced cardiovascular disease risk factors.
2021 Journal of Medicinal Food Influence of Omega-3 Fatty Acid-Rich Fish Oils on Hyperlipidemia: Effect of Eel, Sardine, Trout, and Cod Oils on Hyperlipidemic Mice Kontostathi M, Isou S, Mostratos D, Vasdekis V, Demertzis N, Kourounakis A, et al.
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The study began by inducing dyslipidemia through a high fat diet in a mouse model. After 30 days of this diet, all animals displayed hyperlipidemia. Subsequently, the diet was switched to consist of 90% standard rodent chow and 10% oil derived from different fish varieties (eel, sardine, cod liver, trout). This diet was maintained for the next 60 days. Blood glucose, total blood cholesterol, triglycerides, and high-density lipoprotein were quantified at the end of the study period. Additionally, the fish oils' omega-3 and omega-6 fatty acid percentages and ratio were taken into account by using gas chromatography.
The results showed that incorporating fish oils in the diet considerably improved the hyperlipidemic state triggered by the high-fat diet. Specifically, eel and cod liver oil diets led to significant decreases in triglycerides. Meanwhile, all diets, apart from the standard rodent chow and sardine, resulted in noticeable decreases in blood glucose. Interestingly, smoked eel stood out as the best source for omega-3 fatty acids due to its optimal balance of omega-6 fatty acids, excellently alleviating the mixed hyperlipidemia induced by the high-fat diet.
Consuming oats significantly lessens total and LDL cholesterol levels and mediates a prebiotic effect on the gut microbiome, contributing to its cholesterol-lowering ability.
2021 Frontiers in Immunology The Prebiotic Effects of Oats on Blood Lipids, Gut Microbiota, and Short-Chain Fatty Acids in Mildly Hypercholesterolemic Subjects Compared With Rice: A Randomized, Controlled Trial Xu D, Feng M, Chu YF, Wang S, Shete V, Tuohy KM, et al.
Experimental Study Cholesterol Gut Microbiota Oats
In a randomized controlled study, 210 mildly hypercholesterolemic subjects from three various study centers across China were assigned to consume either 80 g of oats or rice daily for 45 days. To ascertain the effects of these diets, measurements were taken of the participants' plasma lipid profiles, short chain fatty acids (SCFAs), and fecal microbiota.
Following 30 and 45 days of adherence to these diets, there was a pronounced reduction in total cholesterol (TC) and non-high-density lipoprotein cholesterol (non-HDL-C) in both the oat-consuming and rice-consuming participants. This decrease was more articulated amongst the oat consumers by the 45th day. The consumption of oats led to a significant increase in the abundance of certain beneficial gut microbiota and a corresponding decrease in unclassified harmful types. These microbiota demonstrated associations with changes in plasma lipid levels and SCFAs. The comprehensive findings strongly suggest that the cholesterol-reducing effect of oats may be largely down to its prebiotic activity, which modulates the gut microbiome.
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.
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