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Functional foods

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

Also called “nutriceuticals” or “biotherapeutics”

Examples:

Prebiotics

Probiotics

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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

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KEY POINTS

Live micro organisms

Can affect the intestinal flora

Promoted as food supplements

Huge market potential

Many health claims…

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History

Fermented foods rich in probiotics are popular since prehistoric era eg: yoghurt,pickled vegetables..
Metchnikoff – 1907 – yogurt with Lactobacilli

prolongs life

Parker – 1974 – 1^stto use the term probiotics
Fuller – 1989 – defined probiotics

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Common organisms

Lactobacillus

Bifidobacillus

Saccharomyces cerevaciae..

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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

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Criteria for probiotics

^.▪Able to colonize the intestine

Protect the cells against invasion by pathogens

▪Antagonize carcinogenic and pathogenic flora

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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 !

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The gut microflora

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Symbiosis of gut flora

Specially adapted commensals.. Beneficial to the host

Stimulates immune function Produces antimicrobial substances Trophic effect on intestinal epithelium

Maintains the enterohepatic circulation

Involved in metabolic processes

(i.e., fermentation) in the colon

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Factors affecting normal flora

A n y a c t i o n t a k e n t o k i l l „ b a d ‟

Antibiotics

Infections

Diet (highly processed, low-fiber foods)

Chronic diarrhea

Stress

b a c t e r i a	e s s e n t i a l l y	k i l l s	„ g o o d ‟
b a c t e r i a	a s w e l l .

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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

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Actions of probiotics

Alter host immune responses

stimulate IgA production

↓ proinflammatory cytokines

Produce β-galactosidase,so digest lactose

↓ production of carcinogenic metabolites

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Probiotic Products

Wide range of products

No legal definition

No universal standards

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Prebiotics

•

^.term introduced by Gibson who exchanged

❖The

“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

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Probiotics	Prebiotics
Live microbes	Inert chemicals
Act on gut flora	Act as cofactor for probiotics
Eg:lactobacillus	Eg:lactulose

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Examples

Lactulose

Galactosaccharides

Fructo-oligosaccharides

Isomalto-oligosccharides

Lacto-sucrose

Gentio-oligosaccharides

Xylooligosaccharides

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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

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