tractable pediatric diarrhea (caused by administration of antibiotics) dramatically improved stool frequency and appearance within 3-7 days in all patients (Hotta et al., 1987). (3). "Omniflora," a medicine made up of a lyophilized preparation ofBiftdobacte-rium longum, Lactobacillus gasseri, and E. coli, is being prescribed for stomach and intestinal disturbances in Germany CRenner and Munzner, 1991). (4) A well-recognized fact that breastfed infants are anti-infective and healthier than those fed by formula is attributed to the difference in bifidobac-tena count in total intestinal bacteria, the former 99% and the latter 50% or less (Haene!, 1970, Frisell, 1951; Mata et al., 1969; Roberts et al., 1985; Benno and Mitsuoka, 1986; Kurmann and Rasic, 1991).
• Prevention of Constipation. Through production of high levels of short-chain fatty acids, bifidobacteria also prevent constipation by stimulating intestinal peristalsis (Hosono, 1990) and by increasing fecal moisture with osmotic pressure (Shimoyama et al., 1985; Takahashi et al., 1986; Sumihara, 1987; Ito et al., 1990; Takasoye et al., 1990; Matsunami et al., 1992; Wada et al., 1991; Mutai, 1978; Tanaka and Shimosaka, 1982). In human tests, daily ingestion of 3.0-10.0 g of oligosaccharides achieved an anticonstipation effect within a week. However, the effect was not observed in some heavily constipated patients.
• Protection of Liver Function. The reduction of toxic metabolites by the ingestion of oligosaccharides or bifidobacteria alleviates the detoxifying load of the liver. For example: (1) Dosages of 3.0 g/day of soybean oligosaccharides to a liver cirrhosis (non-A, non-B) patient age 69 who had hepatic comatose and constipation symptoms improved both symptoms in about 5 days (Takasoye et al., 1990). (2) Twelve patients with chronic hepatitis or liver cirrhosis without portal hypertension and 8 patients with liver cirrhosis with severe portal hypertension were treated for about 80 days with milk
•containing a high concentration of B. bifidum (as "Engalan forte" in powder form). In both groups, the serum and urinary toxic metabolites decreased significantly to normal or near-normal ranges, and the improvements in the patients' general well-being were no-
-iceable through increased appetite, ""increased protein tolerance, and an average increase of 2.6 kg in body weight (Muting etal., 1968).

• Reduction of Serum Cholesterol. Reduction in serum cholesterol levels by oligosaccharide ingestion has been shown in human tests (Hata et al., 1983; Yamashita et al., 1984; Hidaka, 1985; Takahashi et al., 1986). Ingestion of 6-12 g of oligosaccharides/ day for 2 wk-3 mo reduced total serum cholesterol by 20-50 dL. It has been shown that lactic acid bacteria, including bifidobacteria, or milk fermented with them, reduce total serum cholesterol (Mann and Spoerry, 1974; Hepner et al., 1979), suppress the increase of serum cholesterol (Aoeh et al., 1986), and increase the ratio of HDL-choles-terol to total cholesterol in females but not in males (Bazzarre et al., 1983).
The serum cholesterol reduction is considered due to the changes in intestinal microflora (Hidaka, 1985). Meanwhile, 12 strains of Lactobacillas aci-dophilus of human origin have been shown to assimilate cholesterol in in-vitro studies (Gilliland and Walker, 1990), and L. acidophilus 2056 is reported to have an inhibitory effect against cholesterol micelles absorption through the intestinal wall (Suzuki et al., 1991). The niacin (nicotinic acid)-forming ability of bifidobacteria (described later) may also be contributing to this phenomenon.
• Reduction of Blood Pressure. Ingestion of oligosaccharides is reported to reduce blood pressure. For example: (1) Administration of 11.5 g/ day of fructooligosaccharides for 5 weeks to 46 hyperlipidemic patients reduced average diastolic blood pressure by 6 mm Hg. The fasting blood sugar was also decreased but not significantly (Hata et al., 1983). (2) Administration of 3.0 g/day of soybean oligosaccharides for a week to 6 healthy adult males age 28-48 decreased average diastolic blood pressure by 6.3 mm Hg. There was a significant negative correlation between the diastolic blood pressure and the ratio of fecal bifidobacteria to total bacteria counts (Masai etal., 1987).
• Anticancer Effect. A considerable number of reports describe the anticancer effects of bifidobacteria in small animal tests (Atsui et al., 1977; Kohwi et al., 1978, 1982; Yasuda et al., 1981, 1983; Taketomo et al., 1983; Fujiwara et al., 1990; Kanbe, 1992b). These anticancer effects are due to immunity enhancements by the cells, cell wall components, and extracellular components of bifidobacteria (Hirota, 1990; Kanbe, 1992b).
• Production of Nutrients. Bifido-

bacteria produce the vitamins B-l, B-2, B-6, B-12, nicotinic acid, and folic acid (Mutai, 1978; Kanbe, 1992a). Bifidobac-teria-fermented dairy products also improve lactose tolerance, calcium absorbability, and digestibility (Hughes and Hoover, 1991). Bifidobacteria, however, cannot produce vitamin K.
Dosages and Side Effects
The effective daily doses of oligosaccharides (pure form) are 3.0 g of fructooligosaccharides, 2.0-2.5 g of galacto-oligosaccharides, 2.0 g of soybean oligosaccharides, and 0.7 g of xylooligo-saccharides. The maximum non-diarrhea-causing doses of soybean oligosaccharides are 0.64 g/kg for men and 0.96 g/kg for women (Hata et al., 1989), and the minimum dose of fructooligosaccharides required to induce diarrhea is 44 g for men and 49 g for women (Spiegel et al., 1994). The acute toxicity of galac-tooligosaccharides is LD50>15 g/kg in rat tests, and nonacute, chronic toxicity tests showed that continuous daily oligosaccharide doses of 4.0 g/kg for 35 and 180 days are safe. Subchronic and chronic toxicity and carcinogenicity studies of fructooligosaccharides in rats revealed no significant adverse effects at doses up to 2.17 g/kg/day (Tokunaga et al., 1986; Clevenger et al., 1988).
The fear of flatulence, even in the case.of soybean oligosaccharides (raffi-nose and stachyose), seems to be unnecessary (Hata et al., 1989; Wada et al., 1991; Matsunami et al., 1992). Daily ingestion of 100 mL of a carbonated soft drink containing 3.0 g of soybean oligosaccharides for 2 weeks caused neither flatulence increase nor diarrhea compared with the baseline (Quaker Oats Co., 1993). This appears to be due to the smaller oligosaccharide dosages used (3.0 g/day) and the absence of synergistic components, such as other bean carbohydrates, which may increase flatulence (Galloway et al., 1971; Murphy et al., 1972; Wagner et al., 1977; Nowak and Steinkraus, 1988; Reddy etal., 1984).
Oligosaccharides vs Dietary Fiber
The fact that oligosaccharides are indigestible by human digestive juices may qualify them to be called low-molecular-weight, non-viscosity-building, water-soluble dietary fibers. The health benefits of oligosaccharide ingestion also resemble those attributed to dietary fiber. However, oligosaccharides do not possess the physical effects of dietary fiber, such as viscosity-increase,

OCTOBER 1994—FOOD TECHNOLOGY   63