Gastrointestinal Responses to Millet and Oats Breakfast Interventions Assessed by MRI

Background: Porridge breakfasts from various grains are a staple source of energy for many populations worldwide. The grains used in the porridges differ between regions, mostly due to the crops historically grown. For example, oats are more common in the Anglo-Saxon countries whilst millet is very common in parts of India and Africa. Consumption of whole grains has been associated with a variety of health benefits ranging from lower blood glucose levels, improved insulin responses, reduced cholesterol and increased diversity of the microbiota. Of particular interest to this study are recent suggestions that different grains, and particularly millet grains, may have enhanced health benefits on glucose and insulin metabolism. This may be due to different rates of digestion and absorption, for example, because of grain specific differences in starch digestibility. This could affect gastric emptying and, in turn, post prandial glycaemia and impact on satiety. However little is known about possible differences in gastric emptying between breakfast porridges from different grains and possible relationship with glucose, insulin and appetite.

The research group in Nottingham has world-leading expertise in imaging foods in the body and gastrointestinal function using non-invasive Magnetic Resonance Imaging (MRI) techniques which are particularly well suited for this kind of investigations study.

Aims:

1. to collect data on postprandial glucose levels and hormone peptide response of isoenergetic breakfast porridges made from oats and pearl millet.
2. to collect data on their gastric emptying and satiety.
3. to compare postprandial glucose levels, gastric emptying and satiety for the treatments 4. to explore relationships between glucose levels, gastric emptying and satiety.

Experimental protocol and methods: 26 healthy volunteers will participate in this 2-way study. They will attend one morning for each study, with the studies separated by approximately a week. Before the test meal, and after that approximately every 15 min for 2 hours the level of sugar (glucose) in their blood will be measured using the finger prick method, as diabetics commonly do to monitor their blood sugars. Venous blood samples will also be collected from a cannula placed in the forearm to measure gut hormones such as Peptide YY, GIP, GLP-1 and insulin. The subjects will be scanned on a research dedicated 1.5T MRI scanner. The subjects will be scanned at baseline, immediately after the test meal and then every 30 minutes for 2 hours postprandially. At baseline and every time the subjects come out of the MRI scanner they will be asaked to rate their feelings of fullness, hunger and appetite on 100mm VAS scales. Each subject will be fed two isoenergetic breakfast meals -one on each visit: Oat and Pearl millet breakfast porridge sourced from supermarkets or food manufacturers. These will be cooked in water to avoid confounding factor with milk. The test breakfast will have 220 kcal (slightly higher than a commonly recommended average portion of ~185 kcal). After this the subjects will be asked to eat as much of a pasta meal as they wish and note how much they have eaten as an objective measure of food consumption. The subjects will also complete a food diary for the rest of the day.