PROBIOTICSDR SANGEETHA P

Functional foodsFunctional foods – substances or supplements administered to obtain a specific result in addition to basic nutrition.

• Also called “nutriceuticals” or “biotherapeutics”

• Examples:– Prebiotics– Probiotics

The concept of probiotics

• Probiotics (Greek) – “for life”

• WHO definition:Live microorganisms which, when administered in adequate amounts, confer a health benefit on the host

KEY POINTS• Live micro organisms• Can affect the intestinal flora• Promoted as food supplements• Huge market potential• Many health claims…

History

• Fermented foods rich in probiotics are popular since prehistoric era eg: yoghurt,pickled vegetables..

• Metchnikoff – 1907 – yogurt with Lactobacilli prolongs life

• Parker – 1974 – 1st to use the term probiotics• Fuller – 1989 – defined probiotics

Common organisms

• Lactobacillus• Bifidobacillus• Saccharomyces cerevaciae..

Criteria for probiotics. Bacteria of human origin

Resist secretions of the upper GI tract

Survive passage through the GI tract

Adhere to human intestinal cells

Criteria for probiotics. Able to colonize the intestine

Protect the cells against invasion by pathogens

Antagonize carcinogenic and pathogenic flora

A few words about the gut microflora..• Intesine is a main component of immune

system

• The gut microflora is an important constituent in the intestine's defence barrier.

• Their number is 10 times the human cells..

• Have collective metabolic activity equal to a virtual extra organ !

The gut microflora

Symbiosis of gut floraSpecially adapted commensals..

Beneficial to the hostStimulates immune function

Produces antimicrobial substances

Trophic effect on intestinal epithelium

Maintains the enterohepatic circulation

Involved in metabolic processes (i.e., fermentation) in the colon

Factors affecting normal flora

Any act ion taken to k i l l ‘bad’ bacter ia essent ia l ly k i l ls ‘good’ bacter ia as wel l .

Antibiotics Infections Diet (highly processed, low-fiber foods) Chronic diarrhea Stress

.• .

Actions of probiotics• Restore the balance b/w ‘Good’ and ‘bad’

bacteria in gut

secrete bactericidal proteins

↓ses the pH• Block the attachment & invasion of

epithelium by pathogens • Improve epithelial barrier function

↑ mucus production

↑ barrier integrity

Actions of probiotics• Alter host immune responses

stimulate IgA production

↓ proinflammatory cytokines• Produce β-galactosidase,so digest lactose• ↓ production of carcinogenic metabolites

Probiotic Products

Wide range of products

No legal definition

No universal standards

Prebiotics • .The term introduced by Gibson who exchanged

“pro” for “pre,” which means “before” or “for.”

Prebiotics : Nondigestible substances that provide a beneficial physiological effect for the host by selectively stimulating the favourable growth or activity of a limited number of indigenous bacteria

Synbiotics : Products that contain both probiotics and prebiotics

Probiotics PrebioticsLive microbes Inert chemicalsAct on gut flora Act as cofactor for

probioticsEg:lactobacillus Eg:lactulose

Examples

Lactulose Galactosaccharides Fructo-oligosaccharides Isomalto-oligosccharides Lacto-sucrose Gentio-oligosaccharides Xylooligosaccharides

Synbiotics

Summary • Microflora of the large intestine protect against pathogenic

bacteria and stimulate development of the immune system

• Probiotics and prebiotics in the diet can modify the composition and some metabolic activities of the microflora

• Do not extrapolate from one strain to another

• Many claims for the potential health benefits of prebiotics remain unproved

• Critically evaluate and use only when data supports

.

.