Researchers from the Quadram Institute, King’s College London, the University of Surrey and the University of Messina showed that preserving the natural structure of plant based foods can limit how quickly fats are exposed to digestive enzymes in the stomach helping to regulate the amount of fat absorbed by the body.
In their research called: In vitro and in vivo modeling of lipid bioaccessibility and digestion from almond muffins: The importance of the cell-wall barrier mechanism they mentioned a previous research that found that by consuming whole almonds, you don't gain weight, however if you eat processed almonds, the results are different.
Investigating why this might be, the researchers provided a study participant with two almond muffins, one made with almond chunks (2 mm) and one made with almond flour, which has much smaller particles (at less than half a millimetre).
The muffins were chewed as normal but instead of swallowing were put into an instrument known as the Dynamic Gastric Model, which accurately mimics the physical and chemical conditions of the human stomach and small bowel, enabling the researchers to calculate how much fat had been released.
After 60 minutes in the model stomach, which is the time calculated for this meal to pass through in humans, over 40% of the total fat content had been released from the muffins made with almond flour, but just under 6% had been released from the muffins made with larger almond chunks. Samples taken from the simulated small bowel showed that after 9 hours of digestion, almost all (97%) of the fat from the muffin made with flour was released, and only 60% of fat in the muffin made with almond chunks was released.
They concluded the research with this: „Here we have demonstrated, using in vitro and in vivo models of digestion, that the bioaccessibility of almond lipid within a complex food matrix is significantly affected by the size of the almond particles in the food. The testing of the same experimental meals in both models was originally performed to allow validation of the in vitro model as a good mimic of human digestion under realistic physiological conditions.
In conclusion, this study confirmed that decreasing the size of almond particles, and therefore reducing the proportion of intact cells, increased the proportion of lipid digested by in vitro and in vivo methods. A significant portion of the lipid remained separated from the digestive enzymes by the physical barrier of intact cell walls within the almond particles, even after 12 h of in vivo digestion. The proportion of lipid digested seemed to be reflected in the blood lipid, glucose and insulin responses, although the structure and composition of the food matrix also had some influence on these results. The coupling of an in vivo mastication step with the in vitro model showed good agreement with the in vivo modeling of digestion, and in future studies this may provide a cheaper alternative for studying complex food systems.“
Read the full research here.