Some pioneering research started in the autumn, the aim of which is to get a better understanding of the interaction between meal, digestion and immune defences. The project will run for three years and is financed by the Research Council of Norway. The Norwegian University of Life Sciences (UMB), the National Institute of Nutrition and Seafood Research (NIFES) and Nofima are participating in the project.
The researchers will study model meals consisting of salmon, broccoli, barley and low fat dairy products, ingredients with a high content of health-promoting constituents. The salmon contributes Omega 3 fatty acids, the broccoli a number of plant substances such as polyphenols, barley brings fibre and low fat dairy products have important proteins.
From raw to processed
Some of the researchers in the project will be following the chosen constituents from fresh materials to fully processed products. The focus will be on achieving as careful a heat treatment as possible, so as to retain the healthy constituents, at the same time as ensuring that the product is safe to eat. The salmon will be heated to different temperatures and the researchers will find out what happens to the fat, the absorption properties and the sensory qualities.
In the broccoli, polyphenols, fibre and pectins will be studied, and in the barley starch and fibre.
“Barley rice is new on the market and can be included as part of a healthy meal. The grains are stripped of their outer coating and it will be interesting to see how many of the healthy constituents remain in the barley, both before and after heating,” says Nofima researcher Stefan Sahlstrøm.
“The components will be measured during various heating processes, such as boil/serve, boil/chill and boil/freeze. When the products are put together into a meal, the constituents are measured at both first and second heating, as happens to ready meals that are sold in the supermarket and heated up before eating,” says Nofima researcher Thomas Rosnes.
From mouth to intestine
Next phase. The food is consumed and the digestion of the individual components is the next stage the researchers are working on. In this phase they will compare human digestive enzymes with “commercial” enzymes from pigs. In order to obtain human enzymes, UMB is collaborating with the intestinal juices factory at Østfold Hospital, where student volunteers are providing intestinal juices. The intestinal juices are gathered by means of a tube through the throat. When researchers are to test products in an artificial mouth-stomach-intestine model, they do this by simulating what happens in the digestive system by adding human enzymes (intestinal juices) or commercial enzymes.
“The aim is for the process to be as similar to the digestive process as possible,” explains professor Gerd Vegarud of UMB.
After this, what has not been digested, such as fibre, is transferred to an artificial large intestine model to simulate what happens in the large intestine. Samples from the different stages of the digestion model will be tested in cell lines. One challenge will be to remove what is naturally broken down in the digestive system so that the tests will be as realistic as possible.
Bacteria in the large intestine
We have reached the large intestine. In this part of the project we shall simulate what happens in the large intestine. The researchers will use human faeces samples in an artificial large intestine model in order to simulate the fermentation of the ingredients of the meal. They will focus particularly on studying how meals affect the microbial community in the intestine.
At the same time, they will be researching the interplay between diet and the immune system in the intestine, and how the diet might affect inflammation in the body. Tests will be carried out using human cell lines and NIFES will also carry out tests with mice.
“Overweight mice could be fed with individual components and whole meals. We will study how the food affects the body’s immune defences and the signalling of fullness,” explains professor Tor Lea.
The metabolic syndrome mystery
The findings of the project will be considered in the context of metabolic syndrome. Metabolic syndrome now affects about 30% of the Norwegian population. The syndrome is characterised by abdominal obesity and at least two of the following: dyslipidemia, insulin resistance, inflammation and high blood pressure. Metabolic syndrome is not in itself a disease, but it increases the risk of the major public health diseases like cardiovascular disease and type 2 diabetes.
“We don’t know how metabolic syndrome arises, but both heredity and environment play a role. There is still much research to be done in this area, and the increase in the number of people with metabolic syndrome shows that we must find out more quickly. The picture is a complex one,” says Nofima researcher Bente Kirkhus, who is project manager for Det sunne måltid (the healthy meal). She refers for example to a new study from Telemark that has shown that overweight children eat more healthily than non-overweight ones. There are strong indications that a high energy intake combined with little physical activity are decisive to the development of obesity and metabolic syndrome, which means it will be important to study how entire meals can affect appetite and fullness.
“Industrially produced food often gets the blame for the increase in obesity and metabolic syndrome, so there is a great need to find out more about the significance of processing and preparation of meals,” says Bente Kirkhus.