Modulation of the peripheral blood transcriptome by the ingestion of probiotic yoghurt and acidified milk in healthy, young men

The metabolic health benefits of fermented milks have already been investigated using clinical biomarkers but the development of transcriptomic analytics in blood offers an alternative approach that may help to sensitively characterise such effects. We aimed to assess the effects of probiotic yoghurt intake, compared to non-fermented, acidified milk intake, on clinical biomarkers and gene expression in peripheral blood. To this end, a randomised, crossover study was conducted in fourteen healthy, young men to test the two dairy products. For a subset of seven subjects, RNA sequencing was used to measure gene expression in blood collected during postprandial tests and after two weeks daily intake. We found that the postprandial response in insulin was different for probiotic yoghurt as compared to that of acidified milk. Moreover changes in several clinical biomarkers were associated with changes in the expression of genes representing six metabolic genesets. Assessment of the postprandial effects of each dairy product on gene expression by geneset enrichment analysis revealed significant, similar modulation of inflammatory and glycolytic genes after both probiotic yoghurt and acidified milk intake, although distinct kinetic characteristics of the modulation differentiated the dairy products. The aryl hydrocarbon receptor was a major contributor to the down-regulation of the inflammatory genesets and was also positively associated with changes in circulating insulin at 2h after yoghurt intake (p = 0.05). Daily intake of the dairy products showed little effect on the fasting blood transcriptome. Probiotic yoghurt and acidified milk appear to affect similar gene pathways during the postprandial phase but differences in the timing and the extent of this modulation may lead to different physiological consequences. The functional relevance of these differences in gene expression is supported by their associations with circulating biomarkers

Functional foods as source of bioactive principles. Some marked examples

Functional foods are those that have a beneficial effect on health beyond the basic function of nutrition, helping to promote better health conditions and to reduce the risk of various diseases. This concept was created in Japan in the 1980s and is widely used around the world. The regulation of these products is made by different authorities and has not been defined yet in many countries. The field of food production has increased and changed considerably in the last decades, since the consumers believe that foods, besides satisfy hunger and to provide necessary nutrients for humans, also contribute directly to improve their health conditions. The present chapter will focus with marked examples the main categories of functional foods and respective therapeutic potential (cardioprotective, hepatoprotective, hypolipidemic, antioxidant, anticancer, anti-inflammatory properties, etc.) as well as the active principles responsible for the medicinal properties (flavonoids, alkaloids, terpenes, etc.), including curcuma, garlic, olive oil, grape, broccoli, and probiotic, among others