Short chain fructooligosaccharides (scFOS) – ADULTS: Numerous studies have been performed in healthy human volunteers demonstrating the significant enhancing effect of daily scFOS administration on increasing numbers of beneficial microflora. For example, the effect of scFOS intake (1, 3 & 5 g/day) on the intestinal microflora was studied in 27 healthy volunteers. Testing was conducted for six weeks divided into 3 periods; (i) 2 weeks before scFOS intake, (ii) 2 weeks during scFOS intake and (iii) 2 weeks after scFOS intake. Fecal sample results are presented graphically in the image below and demonstrate a significant increase in Bifidobacterium numbers for scFOS intake period at all three dose levels but all returning to base line values after 2 weeks off the treatment.
Oligofructose-enriched Inulin – ADULTS: Similar dose response studies have been conducted with inulin samples of varying degrees of polymerization (DP) but the lowest dose included in the studies was 5 grams per day. One study evaluated the bifidogenic efficacy of 5 and 8 grams oligofructose-enriched inulin daily during a 2-week intervention trial in healthy human adults in a double-blind, placebo-controlled, crossover human study. The results showed that bifidobacteria levels increased significantly upon ingestion of both low and high doses compared to placebo.
EGCG (Green tea extract) – ADULTS: The beneficial effects of green tea catechins on fecal microflora were demonstrated in a study involving 15 elderly subjects (average age 70.3 years) in a long-term care facility. All subjects received the same daily diet supplemented with 100 mg green tea catechins immediately before each meal (daily catechin intake 300mg – ~100mg EGCG). The protocol was continued for a period of 21 days at which time the supplement was discontinued for a 6-day period. Fecal samples were collected at 0, 7, 14, 21 and 27 days for fecal microbial analyses and the results demonstrate significant increases after only 7 days administration for bifidobacteria and after 21 days for lactobacilli numbers. Significant decreases were also observed in clostridia and Enterobacteriaceae numbers (see image below) which demonstrates the select antimicrobial action of catechins, especially EGCG the only catechin to reach the colon virtually intact.
In vitro studies have demonstrated the antibacterial activity of EGCG against known pathogens such as Helicobacter pylori and E. coli and Staphylococcus aureus strains. In the latter study EGCG was found to exhibit both pro- and antioxidant activities, depending on both pH and oxygen content of the surrounding medium.
 Togunaga T et al (1993) Effects of fructooligosaccharides on the intestinal microflora and defecation in healthy volunteers Bifidus 6:143-150.
 Kolida S et al (2007) A double-blind placebo-controlled study to establish the bifidogenic dose of inulin in healthy humans. European Journal of Clinical Nutrition 61:1189-1195.
 Goto K et al (1998) The influence of tea catechins on fecal flora of elderly residents in long-term care facilities. Annals of Long-Term Care 6(2):1-6.
 Mabe K et al (1999) In vitro and in vivo activities of tea catechins against Helicobacter pylori. Antimicrobial Agents and Chemotherapy 43(7):1788-1791.
 Arakawa H et al (2004) Role of hydrogen peroxide in bactericidal action of catechin Biological and Pharmaceutical Bulletin 27(3):277-281.