Prebiotic diet changes neural correlates of food decision-making in overweight adults: A randomized controlled within-subject cross-over trial
Research suggests that plant-based foods and prebiotic nutrients can modulate brain function through the microbiota-gut-brain axis, potentially influencing feeding behavior and psychological functioning. Functional MRI (fMRI) studies indicate that when people are presented with highly palatable food cues, their brains exhibit stronger responses in reward-related areas compared to responses to equicaloric, non-palatable food cues. This randomized, controlled, cross-over study tested the effects of a high-dose of prebiotic fiber on reward-related food decision-making. Specifically, fifty-nine young adults with a body mass index (BMI) between 25-30 kg/m2 were randomized to consume either 30 g/day of the prebiotic inulin for 14-days, followed by an equicaloric placebo for 14-days, or vice versa. A 14-day washout period separated the two phases. Fasted blood samples and anthropometric measurements were collected at baseline and after the intervention to assess serum short-chain fatty acids (SCFA), markers of glucose/lipid metabolism, inflammation, and gut hormones including ghrelin, glucagon-like peptide-1 (GLP-1) and peptide tyrosine tyrosine (PYY). Stool samples were collected 1-2 days prior to testing to analyze SCFA and microbial markers. On test days, participants received a neutral drink containing approximately 10% of their individual daily energy requirement, and underwent fMRI, where sets of images were presented with the question ‘How much do you want this now?’, followed with further surveys and questionnaires. The results revealed that when compared with a placebo, participants consuming prebiotics had significantly decreased brain activation towards high-caloric food stimuli in the ventral tegmental area and right orbitofrontal cortex of the brain. Changes in brain activation correlated with changes in Actinobacteria microbial abundance and associated activity linked to SCFA production, such as ATP-binding cassette (ABC) transporter metabolism. Prebiotic supplementation also led to significant shifts in the microbiome towards increased occurrence of SCFA-producing Bifidobacteriaceae and changes in functional signalling pathways. Further studies are warranted to link the prebiotic treatment-induced changes in brain response to beneficial behavioural control and underlying implications for addressing unhealthy eating behaviours or overnutrition.
Key takeaways:
- The gut microbiome has been implicated in feeding behaviour through modifying gut-brain crosstalk.
- This study investigated the effects of 30 g/day inulin supplementation on reward-related food decision making in overweight adults.
- Results demonstrate that dietary prebiotics cause a reduction of reward-related brain activation in response to high-caloric food stimuli.
- Future studies may investigate if prebiotic induced changes in brain reward activation implicate eating behaviours.
Access to the study: https://pubmed.ncbi.nlm.nih.gov/37793780/
Reference: Medawar, E., Beyer, F., Thieleking, R., Haange, S.B., Rolle-Kampczyk, U., Reinicke, M., Chakaroun, R., von Bergen, M., Stumvoll, M., Villringer, A., & Witte, A.V. (2024). Prebiotic diet changes neural correlates of food decision-making in overweight adults: a randomised controlled within-subject cross-over trial. Gut microbiota, 73(2), 298-310. https://doi.org/10.1136/gutjnl-2023-33036
Effects of human milk oligosaccharide 2’-Fucosylactose ingestion on weight loss and markers of health
Human breast milk contains several bioactive compounds that have been reported to promote health and immunity. 2’Fucosyllactose (2’FL) is an oligosaccharide found in human milk that have prebiotic and anti-inflammatory properties and is thought to help reduce skeletal muscle atrophy during periods of caloric restriction. This randomized, double-blind, placebo-controlled study aimed to evaluate the effects of 2’-FL supplementation combined with exercise (10,000 steps/day for five days/week) and a daily energy reduction of 300 kcals. The study focused on changes in body composition and health-related biomarkers in overweight and sedentary adults. Specifically, forty-one participants received either 3 g/day of 2’FL or 3 g/day of a maltodextrin placebo, to be dissolved and ingested in the morning with 8 ounces of water, while undergoing an exercise and weight-loss program. Fasting blood samples were taken at baseline, week-6, and week-12 following the intervention to assess blood lipids and inflammatory, glucoregulatory, protein, bone, and liver function markers. Additionally, questionnaires, anthropometric measures, resting energy expenditure, and cardiopulmonary exercise tests were completed. The results showed similar weight reductions for both groups; however, the 2’-FL group had significantly greater reductions in body fat percentage, with a lesser reduction in fat-free mass compared to the placebo group. There was also evidence that the 2’-FL supplementation promoted more favorable changes in resting fat oxidation, peak aerobic capacity, IL-4, and platelet aggregation. Additionally, participant’s perceptions regarding some aspects of functional capacity and ratings of quality of life were improved. The supplementation protocol was well tolerated; however, there was a small but significant decrease in bone mineral contents of the 2’-FL group. Overall, these results demonstrate the ability of dietary 2’FL to promote fat loss, improve exercise, and diet related health markers in overweight and sedentary adults. Further research is needed to explore the pharmacokinetics to establish a dose-response relationship.
Key takeaways:
- 2’Fucosyllactose (2’FL) is an oligosaccharide in human milk that possesses prebiotic and anti-inflammatory properties.
- This study demonstrated significantly greater reductions in body fat and less loss of fat-free mass compared to placebo, when combined with an exercise and diet regimen.
- Further research is needed to explore the pharmacokinetics of 2’FL.
Access to the study: https://www.mdpi.com/2072-6643/16/19/3387
Reference: Ko, J., Yoo, C., Xing, D., Chun, J., Gonzalez, D.E., Dickerson, B.L., Leonard, M., Jenkins, V., van der Merwe, M., Slupsky, C.M., Sowinski, R., Rasmussen, C.J., & Kreider, R.B. (2024). Effects of human milk oligosaccharide 2’-Fucosyllactose ingestion on weight loss and markers of health. Nutrients, 16(19), 3387. https://doi.org/10.3390/nu16193387
Effect of weight loss program using prebiotics and probiotics on body composition, physique, and metabolic products: longitudinal intervention study
Obesity is a worldwide problem that affects individuals across all socioeconomic classes, ages, races, and genders. The gut microbiome plays a vital role in health maintenance, including the metabolism of indigestible dietary components and synthesis of essential vitamins. Furthermore, the gut microbiome is thought to influence body weight and composition. This longitudinal, follow-up, intervention study aimed to evaluate the effects of hypocaloric, fiber-rich regimen (prebiotics) and probiotic supplementation, combined with physical exercise, on health markers, body composition, and physique in obese adult women. Specifically, fifty-eight obese females participated in a weight loss plan that included a dietary plan with low carbohydrate, adequate fiber/prebiotic, and sufficient protein. Each participant consumed 100 grams of probiotic yogurt, which contained Lactobacillus acidophilus and Bifidobacteria strains, and were additionally instructed to exercise regularly, for a duration of three months. To reach the goal of a reduced carbohydrate and increased fiber diet, participants were instructed to follow an eating regimen that was rich in whole grain products, beans, legumes, nuts, dark-coloured vegetables, and fruits like bananas and guava. Anthropometric measurements, body composition, blood sampling, and microbiota analysis were obtained from each participant at baseline and after the 3-month weight loss program. Overall, the results demonstrated statistically significant reduction in various anthropometric and body composition parameters. This included decreases in body weight, BMI, waist and hip circumference, subscapular and abdominal skin fold thickness, fat mass, and fat free mass. Additionally, there was a reduction in obesity-related biomarkers, such as serum leptin, alanine transaminase (ALT), and aspartate aminotransferase (AST) following the intervention when compared to the baseline. Prebiotic and probiotic supplementation led to significant alterations in gut microbiota with increased relative abundance of Lactobacillus, Bifidobacteria, and Bacteroidetes, and decreased relative abundance of Firmicutes and Firmicutes/Bacteroidetes ratio. This study demonstrated that long-term prebiotic and probiotic supplementation is effective in positively impacting body composition and serum leptin, ALT, and AST. Further studies are warranted to confirm these results, and to investigate the individual influences of prebiotics or probiotics.
Key takeaways:
- The gut microbiome plays an important role in maintaining health and may influence body weight and body composition.
- Following a fiber-rich prebiotic diet and the consumption of 100 g/day of probiotic yogurt for 3-months significantly decreased body weight, fat mass, serum leptin, ALT, and AST in obese females.
- Further research is needed to investigate the individual influences of prebiotics or probiotics on these parameters.
Access to the study: https://www.nature.com/articles/s41598-024-61130-2#citeas
Reference: Hassan, N.E., El-Masry, S.A., El Shebini, S.M., Ahmed, N.H., Mehanna, N.S., Wahed, M.M., Amine, D., Hashish, A., Selim, M., Afify, M.A., & Alian, K. (2024). Effect of weight loss program using prebiotics and probiotics on body composition, physique, and metabolic products: longitudinal, intervention study. Scientific Reports, 14, 10960. https://doi.org/10.1038/s41598-024-61130-2
Oligofructose-enriched inulin consumption acutely modifies markers of postexercise appetite
Over the last three decades, the incidence of obesity and adipose-related chronic diseases has increased steadily. While exercise interventions are helpful in combating weight gain and associated chronic disease, these interventions alone have not shown to yield anticipated weight loss for many individuals, potentially due to compensatory energy intake following exercise. Research has demonstrated that the consumption of prebiotics, specifically inulin-type fructans (ITF), have the potential to induce satiety by enhancing the secretion of glucagon-like peptide-1 (GLP-1) and peptide YY (PYY), while also reducing the secretion of the orexigenic hormone acyl-ghrelin. This randomized, crossover study investigated the acute impact of consuming a 50/50 mixture of oligofructose and inulin (OI) following an exercise bout, on subjective and objective measures of satiety and compensatory energy intake. Specifically, fourteen participants completed 45 minutes of cycling exercise (65-70% VO2 peak) and then received either sweetened milk (SM) or sweetened milk with 20 g OI (SM +OI) to consume immediately after. Blood samples were collected pre-exercise, one hour post exercise/post drink, and the following morning in a fasted state. The samples were then measured for GLP-1, PYY, and acyl-ghrelin levels. Appetite and gastrointestinal perceptions were assessed using visual analogue scales (VAS) at blood draw times and following the ad libitum breakfast meal. There was a minimum of one week washout between trials. At baseline, GLP-1, PYY, and acyl-ghrelin did not differ between conditions. The study found that perceived measures of hunger were significantly reduced in the SM + OI group relative to the SM group. Additionally, the plasma concentrations of GLP-1 and PYY were significantly increased and acyl-ghrelin significantly decreased from pre-exercise to post-exercise in the SM + OI group, but not significant in the SM group. Energy intake during the ad libitum breakfast in the morning trended lower in the SM + OI group. Overall, these results demonstrate that ingestion of a single dose of OI after an exercise session appears to induce subtle reductions in appetite, although the impact of these changes on acute and prolonged energy intake remains unclear.
Key takeaways:
- There is a widespread belief that exercise is highly effective for weight loss, yet exercise training has not been shown to yield anticipated weight loss.
- Prebiotics, including inulin-type fructans (ITF) have demonstrated potential to induce satiety by enhancing GLP-1, PYY, and reducing orexigenic hormones.
- This study investigated the effect of an acute supplement of 20 g of oligofructose-enriched inulin (OI) following an exercise bout on appetite sensations and subsequent energy intake.
- OI significantly reduced hunger relative to a placebo group, and plasma concentrations of GLP-1 and PYY were increased and acyl-ghrelin reduced from pre-exercise to postexercise.
- Future studies should explore long term post-exercise supplementation of ITF on appetite sensations and related hormones.
Access to the study: https://www.mdpi.com/2072-6643/15/24/5017
Reference: Hamilton, C., & Bomhof, M. (2023). Oligofructose-enriched inulin consumption acutely modifies markers of postexercise appetite. Nutrients, 15(24), 5017. https:// doi.org/10.3390/nu15245017
