Glycemic and Hormone Responses After the Intake of Four Types of Bread.

The postprandial blood glucose concentration appears to play a critical role in the development of diabetes and cardiovascular diseases; it is largely influenced by the carbohydrate load of a meal. Thus, advocating carbohydrate (CHO) foods that promote favorable glycemic and insulinemic responses, with maintenance of satiety high over a longer period, may be a beneficial approach against many chronic diseases.

Bread is a basic food in Italian feeding. The industrial production of bread is gradually replacing the craft production by small bakeries. It is possible to buy daily bread obtained by completing baking carried out directly at the point of sale from pre-cooked and frozen dough. The use of "improver" as enzyme preparations such as alpha-amylase, improves the quality of bread. A study has found that trestatin, an amylase inhibitor incorporated into bread, produced lower glycemic and insulinemic responses; another has reported that bread made from the ancient wheat Einkorn (Triticum monococcum) elicited a reduced production of glucose-dependent insulinotrophic polypeptide (GIP).

The objectives of the present study are to determine the glycemic and insulinemic responses (area-under the curve, AUCs), the satiety rate and the AUCs of free fatty acids (FFA), triglycerides and ghrelin after the ingestion of four types of breads, each containing 50g of available CHO:

• 97 g handcrafted bread made with wheat organic flour;
• 97 g handcrafted bread with wheat flour of large-scale retail distribution;
• 94 g handcrafted bread with organic einkorn flour
• 86 g commercial precooked-frozen white bread.

16 healthy volunteers participated to this randomized cross-over trial. Each participant consumed the specific portion of a type of bread in the morning, after 8-12 h fasting. The other 3 types of bread are consumed by participants in the order determined by the randomization procedure, after a week each other.

At enrollment, all participants meet the inclusion criteria (see below). Nutrition and exercise advices are given for the day before each bread test. Participants should consume the bread portion in 15 minutes.

Blood samples are drawn every 30-min from fasting until 120-min after bread consumption. The following variables are evaluated at each time point: glucose, insulin, FFA, triglycerides, acylated ghrelin. The satiety rate is estimated every 30-min by the Satiety Labeled Intensity Magnitude scales.

Inclusion criteria

• body mass index (BMI) between 18 and 25 kg/m2
• healthy
• Accept to participate in the study

Exclusion criteria

• smokers
• subjects suffering from any diseases
• drug therapy
• dietary supplementation
• patients unable to give informed consent to participate in the study