As the UK marks National Bagel Day on Thursday 15 January 2026, food lovers are being encouraged to look beyond the standard options. A sourdough bagel, often overlooked, is emerging as a significantly healthier alternative, particularly for those keen on supporting their digestive system and overall wellbeing.
The Science Behind the Starter
The key difference lies in how sourdough is made. Unlike regular bread, it uses a live starter culture of wild yeast and bacteria, not commercial yeast or chemical additives. This starter ferments at room temperature for about a week, a process that naturally produces beneficial bacteria and yeast.
According to experts at the University Hospitals Cleveland Medical Center, this fermentation is crucial. The yeast breaks down starches and gluten in the flour, which unlocks the bread's health benefits. These include essential minerals like zinc, iron, and magnesium, vital for immune function and healthy blood flow.
"Fermentation makes sourdough bread easier to digest by breaking down certain carbohydrates that are poorly absorbed," the centre explains. This can make it a suitable choice even for some people with mild gluten sensitivities.
Blood Sugar and Digestive Benefits
The fermentation process also positively impacts blood sugar levels. The Mayo Clinic notes that sourdough has a lower glycemic index than white bread, meaning it releases sugars into the bloodstream more slowly. This helps avoid sharp spikes in blood sugar, a risk factor for serious conditions like heart disease and diabetes.
For gut health, the benefits continue. While the live probiotics don't survive baking, sourdough contains prebiotic fibres. These act as food for the trillions of bacteria in our gut microbiome. Dr. Ulysses Wu of Hartford HealthCare advises, "When buying sourdough, look at the ingredient list. The best versions have just flour, water, and salt." He recommends opting for whole grain flour for added fibre.
A Fibre-Rich Choice for Fullness
A typical sourdough bagel contains between two and four grams of fibre. Grace Whitmer, a senior clinical dietitian at MD Anderson Cancer Center, highlights the role of this fibre: "It can help keep blood sugar stable by slowing digestion, help lower blood cholesterol, and aid weight management by keeping us full longer after a meal."
Breads high in fibre promote satiety and contribute to more stable blood glucose levels. So, this National Bagel Day, choosing a simple, well-made sourdough bagel could be a delicious step towards better health.
