The Influence of Various Types of Functional Bread on Postprandial Glycemia in Healthy Adults

Bread is a crucial component of a balanced diet. Increasing the choice of functional bakery products based on whole grain flours, with the addition of seeds and grains, can improve health, including reducing postprandial glycemia and the risk of metabolic syndrome. The current study attempted to characterize the relationship between the composition and nutritional value of 23 different types of functional bread and postprandial glycemic response values. This study involved 209 non-obese healthy volunteers aged between 18 and 50. The study protocol followed the standard glycemic index (GI) method outlined by the International Standard, ISO 26642:2010. Most of the examined bread had a low GI and was composed mainly of rye, oats, buckwheat flour with a sourdough starter, and oilseeds. Postprandial glycemia was negatively associated with the fat, protein, and fiber content of bread. However, the GI depended directly on the carbohydrate content and, inversely, on the fat content in wheat bread and bread containing oilseeds. Similarly, using whole-grain flour and sourdough in a functional bakery reduces the GI. Adding oilseeds and sourdough to bread also reduced blood glucose levels approximately one hour after a meal. A greater number of ingredients in a recipe may be associated with a higher GI. In designing a functional bread with a potentially beneficial effect on postprandial glycemia, the nutritional value, type of fermentation, and additives (type and number) are worth considering. The high variability in postprandial glycemia after bread consumption is related to several factors and requires GI determination according to standard methods to ensure that the information provided to the consumer is reliable.