The purpose of the study was to investigate the dose-response effect of increasing doses of Bifidobacterium animalis ssp lactis (BB-12) and Lactobacillus paracasei ssp paracasei (CRL-431) on the immune response, blood lipids, gut microflora, recovery from feces and overall tolerance in healthy young adults.

The study included seventy-one healthy young vounteers, and was designed as a double-blind placebo controlled dose-response trial based on a 2 wk run-in period, a 3 wk intervention and 2 wk wash-out period. The subjects were randomly assigned into 5 groups of 15 subjects each, who were supplemented with 0, 10E8, 10E9, 10E10 or 10E10 CFU/d, respectively, og a mixture of BB-12 and CRL-431. Blood samples were collected 4 times and fecal samples 3 times. Diary reporting bowel habits and weel being was kept for all 7 weeks.

There are very few articles concerning the issue dose-response effect of probiotics.The aim of the study was to investigate the dose-response effect of increasing concentrations of probiotics on the immune response, blood lipids, composition of the gut microflora, recovery from feces and the overall tolerance.

The hypothesis was that the increasing dose would influence the immunresponse (eg incresae phagocytosis), improve blood lipid profile (eg.lower HDL-cholesterol), would be recovered in increasing concentrations in feces, would change the intestinal microfloraprofile and would be well tolerated even in high doses.

Inclusion Criteria:

• Healthy young individuals

Exclusion Criteria:

• GI-disease
• Colosomi
• Pregnant or lactating women
• Allergy
• Individuals receiving the following medicine: antacid, antibiotics, steroids, medicine with influence the intestinal function.