Effects of a Probiotics on the Health of Normal Young Males (FFF)

The important role played by the GI tract microflora on the metabolic health of an individual are increasingly recognized. In this respect, the initial studies of Metchinkoff that suggested a role of fermented food (specifically yoghourts ) to modulate the gut microflora have evolved into the concept of "probiotics". Probiotics are living microorganisms that bring a benefit to the host when administered in sufficient quantity (WHO/FAO, 2001). Here the investigators will study, in normal young male volunteers, the potential to modulate post-prandial metabolic and inflammatory responses by the administration of a yoghourt containing the probiotic Lactobacillus rhamnosus (LGG).

This is a prospective, randomized, double-blind and cross-over study designed to evaluate the potential of a probiotic (Lactobacillus rhamnosus) to modulate the post prandial metabolic and inflammatory response of normale healthy individuals. After a wash out period during which volunteers will have to follow a diet devoid of all milk or milk-derived products, they will receive, in random order, either a daily dose of the probiotic, or a daily dose of acidified milk (control) for a total of three consecutive weeks. At the end of each of these period, they will be submitted to a day of investigation, during which their metabolic and inflammatory profile will be studied following the ingestion of a standard test meal. The potential for the probiotic to modulate the metabolic and inflammatory parameters will be evaluated. The test meal will provide 1004Kcal under the form of 45.4g proteins (17%), 69g total fatty acids (62%), and 52.6g glucids (21%) as previously published (Schwander et al, J Nut 2014).

Daily administration, over two consecutive weeks, of an isocaloric dose (compared to probiotics) of unfermented acidified milk

Probiotic yogurt (fermented milk with Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus- YoFlex FD-DVS YC-X11 Fr, with the addition of Lactobacillus rhamnosus GG (LGG)- Culture Collection, University of Göteborg, Sweden CCUG 34291).

Kinetics of metabolomic changes in blood during the 6 hours after meal ingestion, in presence of yogurt or placebo

Kinetics of total cholesterol during the 6 hours after meal ingestion, in presence of yogurt or placebo

Kinetics of LDL-cholesterol during the 6 hours after meal ingestion, in presence of yogurt or placebo

Kinetics of HDL-cholesterol during the 6 hours after meal ingestion, in presence of yogurt or placebo

Kinetics of IL-6 will be measured in blood of volunteers after the administration of yogurt or placebo

Kinetics of CCK2 will be measured in blood of volunteers after the administration of yogurt or placebo

Kinetics of CCK5 will be measured in blood of volunteers after the administration of yogurt or placebo

Kinetics of TNF-a will be measured in blood of volunteers after the administration of yogurt or placebo

Kinetics of LPS will be measured in blood of volunteers after the administration of yogurt or placebo

Kinetics of gene expression in white blood cells during the 6 hours after meal ingestion, in presence of yogurt or placebo

Inclusion Criteria: Normal male with normal BMI (18.5-25 kg/m2) non smoker stable physical activity Exclusion Criteria: Food intolerance (ceoliac disease, lactose intolerance, food allergies) Particular regimen (vegetarian...) Chronic disease (any) Elevated blood pressure Regular drug treatment Antibiotics treatement in the preceding six months >4 hrs/week of physical activity

Vionnet N, Munger LH, Freiburghaus C, Burton KJ, Pimentel G, Pralong FP, Badertscher R, Vergeres G. Assessment of lactase activity in humans by measurement of galactitol and galactonate in serum and urine after milk intake. Am J Clin Nutr. 2019 Feb 1;109(2):470-477. doi: 10.1093/ajcn/nqy296.

Pimentel G, Burton KJ, von Ah U, Butikofer U, Pralong FP, Vionnet N, Portmann R, Vergeres G. Metabolic Footprinting of Fermented Milk Consumption in Serum of Healthy Men. J Nutr. 2018 Jun 1;148(6):851-860. doi: 10.1093/jn/nxy053.