Blood Sugar The Sourdough School Magazine by Dr Vanessa Kimbell

What Is Blood Sugar?

Blood sugar, or blood glucose, refers to the concentration of glucose in the bloodstream. Glucose is a type of sugar that serves as the body’s main energy source, especially for the brain and muscles. It comes primarily from the carbohydrates in food and is regulated by hormones, mainly insulin.

Maintaining stable blood sugar levels is essential for overall health. Spikes and crashes can affect energy, mood, appetite, and long-term metabolic function. Chronic imbalances may lead to conditions such as type 2 diabetes or insulin resistance.

Blood Sugar and Bread

Not all breads affect blood sugar in the same way. Highly processed white bread often causes a rapid increase in blood glucose, followed by a quick drop. In contrast, long-fermented breads, such as those made using sourdough fermentation, tend to release glucose more slowly.

This slower response is linked to:

A reduction in simple sugars through fermentation
The presence of dietary fibre in wholegrain flours
The impact of lactic acid bacteria on the glycaemic response

Why Blood Sugar Stability Matters

Stable blood sugar levels support:

Sustained energy without sharp peaks and crashes
Balanced mood and reduced cravings
Lower risk of metabolic disease
Improved focus and mental clarity
Gut–brain communication and overall digestive health

For those with insulin sensitivity or diabetes, choosing bread that has a slower glucose impact, like sourdough made from botanical blend flour can be part of a supportive dietary approach. It is also essential to work with a healthcare professional to manage blood sugar effectively.

Sourdough and Blood Sugar: Research Insights

Several studies suggest that sourdough fermentation can lead to a lower glycaemic response when compared to yeasted breads. This is due in part to organic acids and the action of wild yeasts and bacteria.

At The Sourdough School, we teach techniques that focus on fermentation as a tool for supporting blood sugar regulation. We also work with doctors and nutritionists to integrate these approaches into lifestyle medicine.

All reasonable care is taken when writing about health aspects of bread, but the information it contains is not intended to take the place of treatment by a qualified medical practitioner. You must seek professional advice if you are in any doubt about any medical condition. Any application of the ideas and information contained on this website is at the reader's sole discretion and risk.