Effects of lipids composition and structure in meat and dairy foods on digestibility and low-grade inflammation in cell, animals and humans

The project has had 4 active work packages (WP) of which WP1's research focus was to determine fatty acids in SN2 positions using a quantitative 13C NMR method directly on intact triglycerides. High-field NMR and advanced signal processing found the dominant fatty acid in the SN2 position for pork fat (C16:0) and cattle fat (C18:1). The approach is scientifically new. It was not possible to distinguish 16:0 and 18:0 in the different positions in cattle fat. Unfortunately, the method could not be applied to milk fat because of its great a variation in fatty acid composition. For milk fat the strategy has therefore, been to analyze mono and diglycerides after enzymatic hydrolysis. This has, however, been challenging due to isomerization (the fatty acids change position) and thus one cannot say for sure the fatty acid in the SN2 position. Different methodology to avoid this isomerization has been tried, this work has not been completed due to a maternal leave. Calcium soaps were largely formed from saturated and unsaturated trans fatty acids, while un saturated cis fatty acids did not form calcium soaps. When digesting dairy products that are high in calcium, we saw that calcium soaps were formed, but this also depended on other factors of the product such as pH, texture and protein condition (e.g. degree of ripening of cheese). We have looked at the ability of various fatty acids to form such soaps in an in vitro digestive system in both dairy and meat products. WP3 was a large mouse experiment in which dairy, cattle and pig fat were compared to sunflower oil and a mixture of rapeseed/olive oil in a long experiment corresponding to about 20 human years between 30 and 50 years. The aim was to look at the development of arteriosclerosis during this period, and this was assessed by looking at lesions in the heart root. The total lesion area was ranked like this: plant oils < pork fat < cattle, milk fat. Nevertheless, the ranking depends on the size of the lesions. The mouse experiment was also used to relate various fats to liver fibrosis. Liver disease is almost as common as heart disease and therefore of interest. The ranking of the fat was the same, but with a significant difference between pork fat and the cattle/milk fat group. WP4 has performed a longer (14 weeks) human intervention with 4 test diets that were crossed four times. The intervention was performed using the participants' usual (habitual) diet as a basis for comparison to a healthy diet with the test products being dairy/milk, cattle and pork fat. Advanced lipidomics (LC MS, NMR) were used on blood plasma to assess the results. This experiment showed that pork fat has more new positive health markers than beef/milk fat. The microbiota was analyzed and the greatest difference was observed between regular and test diet, and minor differences between the test diets. Project also carried out a postprandial human intervention in which pork and milk fats were compared in a breakfast meal in terms of satiety and regulation of satiety hormones. These two types of fats have different fatty acids in the SN2 position, which can affect satiety. We found differences in hormones (ghrelin, glucagon-like peptide 1, gastric inhibitory polypeptide) as well as triglycerides in blood plasma. However, the clinical differences did not lead to significant differences in food intake or expressed hunger/satiety 4 hours after breakfast. The project results is expected to reach 8 publications.

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LipidInflammaGenes takes as a starting point the recent report from The Directory of Health (May 2017) requesting further reduction in consumption of saturated fats (SFA). The project also approaches the fact that accelerating obesity has been reported as causal for cardiovascular diseases. As many pre-disease stages have low grade inflammation as a starting point for heart diseases and obesity, the overarching target of the project is to understand low grade inflammation and its possible relationship to SFA in triacyglycerols(TAGs). A key focus has been put on type of fatty acids present in the different positions of TAGs and how this impact on serum values related to appetite and lipidemia. The structural differences of TAGs from beef, dairy and pork are substantial. By studying these TAGs it seems possible to better understand the impact of these structural differences on health. A clear conclusion regarding structural TAG differences will, as a case study, be linked to novel breeding goals based on pig genetics. The structure of TAGs decides the split between absorption and excretion in the gut and thereby also appetite and lipidemia. A detailed study using in vitro models based on human enzymes, relevant cell and animal models for inflammation and athero-sclerosis will be used to understand pre-disease and disease stages. Inflammagenes we will also study food matrix effects; the effect of calcium is relevant due to its capacity to form soaps with SFA and thereby reduce their absorption. The model studies will determine the input to the human intervention(s) that are planned with measurements of individual genetic sensitivity regarding how genes of cells are read (epigenetics) with higher fat intake,inflammation and appetite markers (blood samples).In addition,feces will be analyzed. The most critical variable is to model power as well as possible for significant results. Clear conclusions may affect product development,breeding goals and consumers' choices.