PREBIOTICS, PROBIOTICS and SYNBIOTICS
NEW OR OLD CONCEPT?
Although the concept of prebiotics and probiotics started in the
1970’s, it was dormant until 1994 when Danone, an European dairy and
confectionary manufacturer, launched Actimel probiotic drinking yogurt in
100 ml daily-dose bottles. Actimel revolutionizes the dietary supplements
market and is now considered as the leading “immunity” yogurt brand
worldwide. Actimel earned over $1.8 billion in retail sales in 2007. The
concept of prebiotics and probiotics reached its peak in April 2008 when the
International Probiotics Association had its World Congress in Los Angeles,
CA. It was the first global prebiotics and probiotics event attended by
industry, academia and health care representatives. A world congress on
nutrients that were ignored or unheard of just 10 years ago.
Worldwide, prebiotics, probiotics and synbiotics are gaining
popularity and their claimed beneficial health effects are now accepted and
trusted by the general population. Daily intake of these supplements (i.e.,
drinking yogurt) is now fashionable among affluent families and young
generation. Consequently, these dietary supplements are now deliberately
added to many products with claims attesting to their health benefits. So, is
daily supplementation with prebiotics, probiotics or synbiotics a truly new
and innovative concept?
Definition of prebiotics, probiotics and synbiotics
Probiotics are living microorganisms, which, when ingested or
locally applied in sufficient numbers, provide the consumer with one or
more proven health benefits. The probiotic strains most commonly used are
Lactobacillus sp. (e.g., rhamnosus, acidophilus, casei, plantarum, reuteri,
etc.), Bacillus breve, Bifidobacteria sp. (e.g., lactis, longum, etc.),
lactococcus lactis and Propionibacterium freudenreichii.
The term “prebiotic” was coined by Gibson and Roberfroid in 1995
to describe ingredients that can boost the growth of beneficial bacteria
(probiotics) in the gastrointestinal (GI) tract. Prebiotics are derived from
insoluble fibers and oligosaccharides and include inulin (beta (2,1) linear
fructans), xylooligosaccharides, lactulose, galactooligosaccharides and
fructooligosaccharides. Prebiotics are thus non-digestible food ingredients
that, when consumed in sufficient amounts, selectively stimulate the growth
and/or activity of one or a limited number of bacteria in the GI tract resulting
in documented health benefits. The most well known prebiotic is inulin,
which is the major polysaccharide in many subsurface tubers and bulbs like
onions and agave. Agave is a plant in Arizona and is used extensively in the
production of tequila (a Mexican hard liquor).
Synbiotic is a mixture of pro- and prebiotics, which beneficially
affects the host by providing the survival and implantation of selected live
microorganisms in the GI tract. The market for prebiotics, probiotics or
“healthy” bacteria and synbiotics continues to grow as awareness of their
health benefits increases. Nowadays, even some manufacturers are
promoting the prebiotic effects as more useful than the probiotic bacteria
that they feed.
Claimed Health Benefits - Prebiotics
Claimed benefits of prebiotics include improved health and immunity,
reduced formation of potentially toxic or carcinogenic compounds (De
Preter et al., 2008), enhanced survival and reduced infections. The potential
of inulin to support bone health and prevent osteoporosis, which affects over
70 millions people in the US, Europe and Japan, is gaining popularity.
Currently, two approaches are being pursued to prevent osteoporosis. The
first approach is to optimize bone mass acquisition during adolescence and
the second approach is to minimize bone loss after menopause. The prebiotic
inulin works through the first approach by increasing colonic calcium
absorption during adolescence. In a study with human adolescents,
supplementation with a mixture of oligofructose and inulin is reported to
result in a higher absorption of calcium (38%) than the placebo group (32%)
(Abrams, 2005). The second approach is that of medications used for the
prevention and/or treatment of osteoporosis (e.g., Fosamax, Boniva, Evita,
etc.). These medications target the dynamic nature of bones by reducing the
rate of bone breakdown or loss. By reducing bone loss, bones can
accumulate bone minerals and increase bone density.
Researchers from Baylor College of Medicine recently discussed their
findings in the Journal of Pediatrics, indicating that a daily supplement of
prebiotics inulin and oligofructose may help adolescents maintain an
appropriate body weight and body mass index (BMI) during pubertal
growth. BMI normally increases during puberty and adolescents
supplemented with prebiotics for one year had a normal BMI of 0.7 kg per
m2 compared to the control group with a BMI of 1.2 kg per m2. The
researchers postulated that inulin and oligofructose may regulate appetite by
increasing GI peptides that modulate satiety such as glucagon-like peptide-
1(GLP-1) and concluded that prebiotics may prevent excessive teenage
weight gain.
The potential benefits of prebiotics for infant health have also gained
increasing acceptance by parents. Infants fed formula contained prebiotics
had a 6.5% lower incidence of recurring respiratory infections than placebo-
fed infants, according to a report by European researchers (Arslanoglu et al.,
2007). The authors indicated that while the exact mechanism of action is not
known, the immune modulating effect of the prebiotics via modification of
the intestinal flora was the likely reason. The study adds to an ever-growing
body of research reporting benefits of the inclusion of prebiotics in infant
formula.
As we age, the microbial flora of the intestinal tract changes with
decreases in levels of the beneficial bifidobacteria and increases in
potentially harmful clostridia, streptococci and enterobacteria. The shift in
the intestinal flora may be the etiology of constipation, colitis, irritable
bowel disease, or colon cancer in the elderly. Prebiotics can normalize the
intestinal flora as substantiated by studies conducted at Providence
University in Taiwan (Chung et al., 2008). The study consisted of elderly
subjects (average age of 78.6) who were fed either a daily supplement of