Exploring the impact of solid oat polar lipid-enriched breakfasts on metabolic health

In a recent study published in Nutrients, researchers investigate whether oat polar lipid compounds incorporated in solid breakfasts improve glucose tolerance, gut hormonal responses, and triglyceridemia postprandially and following a standardized lunch.

Study: Inclusion of Oat Polar Lipids in a Solid Breakfast Improves Glucose Tolerance, Triglyceridemia, and Gut Hormone Responses Postprandially and after a Standardized Second Meal: A Randomized Crossover Study in Healthy Individuals. Image Credit: Timmary / Shutterstock.com

Background

Cardiometabolic disorders have become more common worldwide, thus necessitating the need for immediate preventative interventions. The structure and content of food impact digestion and absorption rates; therefore, diet selection is crucial for the effective prevention of these diseases.

Beta-glucans, the soluble dietary fiber in oats, which are high in vitamins, minerals, antioxidants, and phenolic compounds, effectively reduce blood cholesterol levels.

In young and healthy adults, polar lipids of oats in liquid meals can modify cardiometabolic factors, including reduced postprandial blood glucose responses, increased gut hormones involved in appetite and metabolic regulation, beneficial modulation of triglyceride concentrations, and decreased non-esterified fatty acids.

About the study

In the present randomized single-blinded crossover trial, researchers evaluate the impact of consuming polar lipids of oats in solid breakfast meals on acute and second-meal blood glucose tolerance, serum lipids, and gut-derived hormone levels.

The polar lipids from oats were ingested during breakfast and their effects on biomarkers were studied post-prandially and after a standard lunch. Between June 2020 to August 2020, 20 young and healthy participants were recruited for the crossover study and enjoyed four breakfast menus.

The meals included white wheat bread (WWB) and 7.5 grams of polar lipids of oats (PLL), WWB with 15 grams of polar lipids of oats (PLH), WWB with 16.6 grams of rapeseed oil (RSO), which represented widely used oils, and WWB ingested alone, which served as a control.

The breakfast meals contained 50, 16.6., 8.5, and 385 grams of carbohydrates, fats, proteins, and calories (kcal), respectively. In the standardized lunch, the corresponding nutrient proportions were 58, 18.5, 21.5, and 485 grams, respectively. After 3.5 hours of breakfast, the standardized meal of meatballs and WWB was provided.

Blood glucose, triglyceride (TG), serum insulin, free fatty acids (FFA), glucagon-like peptide-1 1 (GLP-1), ghrelin, glucose-dependent insulinotropic polypeptide (GIP), and peptide YY (PYY) levels were evaluated before and after breakfast. The effects of oat polar lipid consumption were compared to RSO in equicaloric amounts.

Only non-smokers aged 20 to 40 years with body mass index (BMI) values ranging from 19 to 28 kg/m² were included in the study. Individuals with fasting blood glucose levels of 6.1 mmol/L or greater, food allergies, metabolic illnesses, and those who had taken probiotics or antibiotics during the preceding two weeks were excluded from the study. The clinical phase of the trial was conducted between August 2020 and November 2020.

Serum samples were obtained zero, 15, 30, 45, 60, 90, 120, 150, 180, and 210 minutes after consuming the morning meal. Following the 210-minute serum collection, a standardized lunch was served and additional samples were obtained 225, 240, 255, 270, 300, and 330 minutes after breakfast.

Study findings

Among the participants, 13 were female and seven were male, with a mean age of 24 and BMI of 23 kg/m². As compared to RSO and WWB, PLH significantly decreased postprandial glucose levels and attenuated insulin responses after breakfast. Among all breakfasts, the PLH breakfast significantly lowered glycemic responses to lunch.

Fifteen grams of polar lipids of oats and, to a lesser extent, 7.5 grams, may improve acute and second meal glucose tolerance, increase gut hormones associated with appetite and glycemic regulation, as well as improve the postprandial blood lipid profile as compared to an isolipidic amount of an RSO-containing meal and close to fat-free reference meal.

As compared to WWB, PLH and PLL lowered immediate postprandial glucose responses after breakfast; however, no significant effects were observed after RSO. The PLH breakfast also increased glucose tolerance following the standardized lunch meal.

The favorable modification of second-meal glucose tolerance by oat polar lipids is an intriguing health benefit. These findings support the glycemia-modulating characteristics of oat polar lipids.

PYY and GLP-1 levels increased in tandem with better postprandial glucose management. Oat polar lipids in solid meals may diminish hunger sensations and lower ghrelin concentrations before starting the meal at 210 minutes and lead to lower calorie intake throughout the meal. A significant reduction in postprandial triglyceridemia was observed after eating breakfast with oat polar lipids.

Conclusions

Consuming polar lipids of oats in solid meals may enhance glucose tolerance and gut hormone responses, as well as reduce triglyceridemia. Additionally, these components of oats may have anti-obesogenic and anti-diabetic effects and, as a result, can potentially prevent cardiometabolic diseases.

Nevertheless, further research is needed to understand the underlying mechanisms responsible for these health benefits and to apply these findings to plant polar lipids. It is also critical to investigate the long-term effects of polar lipids of oats.