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Van deeg naar volheid: inzicht in het effect van de consumptie van zuurdesembrood op de eetlust, energie-inname en postprandiale metabolische reacties

Year: 2025
Type: dissertation
Abstract: The feeling of satiety is complex, determined by multiple psychological and physiological parameters. In Europe, more than 50% of daily energy intake comes from carbohydrates, with bread being the primary source. Most countries have an average consumption of 50 kg of bread per person per year. As such, the bakery industry has been working to design breads that induce higher satiety by influencing one or more parameters involved in the satiety cascade. Sourdough is a fermented flour-water mixture, where wild yeast and lactic acid bacterial communities develop naturally or are added as starter cultures. Sourdough bread can be produced using only sourdough (so-called sourdough bread) or with added baker's yeast (Saccharomyces cerevisiae) to enhance fermentation (so-called bread with sourdough). During fermentation, microorganisms produce CO2, which increases bread volume, and organic molecules that contribute to flavor. In this PhD project, we hypothesized that sourdough bread consumption may lead to increased satiety and reduced energy intake through two proposed mechanisms. First, acetic acid activates GPR41 and GPR43 receptors on enteroendocrine cells, promoting PYY and GLP-1 production. These hormones decrease gut motility, reduce gastric emptying, promote insulin secretion, and enhance satiety. Second, lactic acid may activate GPR81 receptors on gastric cells, reducing ghrelin production and slowing gastric emptying, resulting in greater satiety. To test this hypothesis, we first explored the mechanisms by which sourdough fermentation might impact parameters of the 'Satiety Cascade' (Chapter 2). Sourdough bread has been extensively studied for its ability to reduce glucose responses compared to white yeast bread or glucose solutions, likely due to organic acids that slow starch digestion, gastric emptying, and glycemic spikes. Nonetheless, limitations in prior studies—such as poor product characterization and inconsistent control products—have hindered accurate assessments. To address these gaps, two randomized controlled trials were conducted to assess the effects of sourdough bread types on appetite regulation compared to bread made with baker's yeast. The first trial (Chapter 3) examined two conventional sourdough breads: one representing bakery-style sourdough (fermented with Fructilactobacillus sanfranciscensis and Maudiozyma humilis -formerly Kazachstania humilis-) and another industrial-style sourdough with added baker's yeast (Fructilactobacillus sanfranciscensis, Maudiozyma humilis, and baker's yeast). In a double-blind, randomized crossover trial, 44 participants (aged 25 ± 4 years, BMI: 22 ± 2 kg/m²) consumed 180g/day of wholemeal bread leavened with baker's yeast (WYB), wholemeal sourdough bread (WSB), or sourdough bread with added baker's yeast (WSYB) over two weeks, separated by a two-week washout. Participants recorded habitual food intake and provided fecal samples for microbiota analysis. On the final day of each intervention, appetite, gastric emptying, and postprandial metabolic responses were measured after a test breakfast (100g of bread). The primary outcome was ad-libitum energy intake at a subsequent lunch. Ad-libitum energy intake at lunch did not differ among the breads. WYB and WSYB were consumed more slowly than WSB and resulted in slightly higher satiety (p < 0.05). WSYB increased C-peptide levels, WYB raised PYY, and both WSB and WYB stimulated higher GLP-1 release (p < 0.05). Gastric emptying, glucose responses, habitual energy intake, cholesterol, and gut microbiota composition were unaffected (p > 0.05). These findings suggest that although some statistical differences were observed among the three types of bread, the overall clinical relevance is limited, as there were no differences in ad-libitum energy intake, glucose response, or gastric emptying rate. Sourdough bread with higher concentrations of organic acids may be more effective in modulating appetite and postprandial responses. The second trial (Chapter 4) investigated a novel sourdough bread, rich in lactic acid, fermented with Companilactobacillus crustorum and Wickerhamomyces anomalus. This study compared the effects of lactic acid-rich WSB with WYB on appetite regulation, energy intake, and metabolic responses. Forty-four participants (aged 30 ± 10 years, BMI: 23 ± 2 kg/m²) participated in a double-blind, randomized crossover trial with two study visits separated by a one-week washout. Gastric emptying, subjective appetite, glucose, and C-peptide concentrations were monitored over four hours after consuming the test bread. WSB reduced hunger (p < 0.001), increased fullness (p < 0.001), and lowered the desire to eat (p < 0.001) compared to WYB. It also slowed gastric half-emptying (p = 0.002) and reduced glucose and C-peptide responses during the first 90 minutes post-consumption (p < 0.05). Despite these acute effects, WSB did not reduce ad-libitum energy intake at the subsequent meal (p = 0.068). In conclusion, conventional wholemeal sourdough bread and wholemeal bread with yeast had similar effects on appetite and postprandial responses. In contrast, novel wholemeal sourdough bread, rich in lactic acid, showed improvements in appetite, glucose response, and gastric emptying compared to wholemeal yeast bread, although it did not affect energy intake at the subsequent meal. Future studies could investigate whether other organic acids present in high concentrations, such as acetic acid or a combination of acetic and lactic acids in sourdough bread, yield similar effects on satiety and metabolic responses. Additionally, examining the impact of long-term sourdough bread consumption over several weeks could provide insights into whether these acute effects persist and influence habitual energy intake. Finally, it would be valuable to explore whether these findings hold true in populations with overweight, obesity, or diabetes, as these groups may exhibit different metabolic and appetite-related responses.
Source: Lirias
Author: Chatonidi, Georgia
Language: English
Open Access status: green
OpenAlex ID: W7112986668
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