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Friday, November 28, 2014

Benefits of Prebiotics



·         Increase good bacteria & reduce harmful bacteria in the gut.
Gut probiotics inhibits growth of harmful microbes.

·         Modulates & enhance immune system.
The enhanced immune system help maintains a disease-free state

Short-chain fatty acids (SCFAs) protect and strengthen mucosa lining. Without the SCFA (butyrates) for energy, colon cells will die.

·         May reduce intestinal infections

·         Reduced abnormal bacterial leakage through the gut wall when taken in        moderation.

·         Synthesize certain vitamins.

·         Increase mineral absorption, leading to stronger bones and increased bone density.

·         Reduce blood triglyceride level.

·         Better weight & appetite management.

·         Alleviate constipation with improved bowel regularity.

·         Reduced flatulence with lessened or no bad smell.

·         Certain SCFAs can prevent allergy.

·         Epidemiological evidence has shown that dietary fiber is beneficial in the clinical management of obesity, diabetes, cancer, and cardiovascular diseases.

·         Dietary fiber improves short chain fatty acid (SCFAs) production, and reduces glycemic response.

·         Moreover, although glucose may serve as the main metabolic fuel, SCFAs produced by colonic bacterial fermentation of dietary fiber furnish a significant portion of daily energy requirement.

·         Reduce risk of inflammatory diseases such as arthritis, IBS etc. due to anti-inflammatory property.

BOOST IMMUNITY

The gut and immune system form a complex integrated structure that has evolved to provide effective digestion and defence against ingested toxins and pathogens indirectly via a healthy population of symbiotic microbes. [Pathology and Neuroscience, University of Dundee, 2004]

In the gut, prebiotics boost immunity in two ways: through intrinsic properties of its compounds and by favoring growth of beneficial bacteria.

Fermentation by colonic bacteria on the food mass produces gases and short-chain fatty acids. It is these short-chain fatty acids—butyric, lactic, acetic (ethanoic), propionic, and valeric acids that lower the pH of the colon enabling inhibition of pathogens growth.

Microbiota (Bifidobacteria and Lactobacilli) provide a barrier by producing antimicrobial substances and/or stimulating mucosal immunity thus reducing chance of infection (Servin, 2004). 

Lactobacilli not only do not produce carcinogen, it inhibits several bacteria that produce carcinogenic enzymes.

A 2002 study found probiotics also secrete biosurfactants that inhibit infections of surgical implants in rats [Gan et al.]

Prebiotics modify the activities of bacteria that are involved in carcinogenesis through substituting their food source from protein metabolism to carbohydrate metabolism. So when you eat more prebiotic food than protein, you are shifting metabolism of Clostridia and Bacteroides towards more benign end products.

Studies indicated   FOS and Oligosaccharides confer the degree of fermentation selectivity towards Bifidobacteria but could not be utilized efficiently by pathogenic ones such as E-coli, Salmonella, and Helicobacter spp.

Certain types of prebiotics such as β-glucans and oligosaccharides stimulate the immune system by interacting with immune cells and through producing antimicrobial substances in the fermentation process leading to inhibition of pathogenic bacteria.

Researchers have shown that certain types of prebiotics (GOS) can prevent allergy and reduce infectious diseases as well as reduce antibiotic use in infants. Human breast milk naturally contain oligosaccharides and are believed to play an important role in the development of a healthy immune system in infants by increasing the body’s immune cells such as T helper cells, macrophages, and neutrophils.

FOS increases butyrate concentrations in the large intestine; in the liver it plays a role in lipid and glucose homeostasis.  It may destroy colonic cancer by stimulating them to commit suicide (apoptosis).

Researchers found that a class of bacteria called Firmicutes can control candida albicans, a yeast infection. Some people proposed it as a supplement for treating yeast infections.

LOWER DISEASE RISK

Scientists speculated Biomarkers that change with fiber intakes, in particular short chain fatty acids and probiotics may play a role in alleviating digestive and inflammatory conditions such as inflammatory bowel disease, irritable bowel syndrome (IBS), systemic anaphylaxis, arthritis,   rashes, allergic rhinitis and asthma). The lower pH reduces peptide degradation and the resultant formation of toxic compounds such as ammonia and amines which can contribute to aforesaid diseases.

Propionate is a microbial fermentation metabolite that lowers liver production of cholesterol by interfering with its synthesis. This resulted in lower risk for coronary heart disease and lower blood pressure. Water-soluble fibers (beta-glucan, psyllium, pectin) as well as resistant starch (gum Arabic, tara gum, locust bean gum/ carob bean gum) were highly effective for lowering serum LDL cholesterol concentrations, without affecting high density lipoprotein (HDL) concentrations.

Test results on the effect of fiber on diabetes were mixed. A comparison of five week controlled diet using oat beta-glucan (5 g) against barley beta-glucan (5 g or 10 g) showed the oat diet was effective in reduced postprandial glucose and insulin responses whereas the barley diet was not. Large-scale cohort studies indicated insoluble fiber was more effective in reducing risk of developing type II diabetes than soluble fiber.

NUTRITION

Bacteria synthesize B and K Vitamins, which are absorbed through the gut.

Researchers found probiotics Lowers pH in the large intestine, leading to better calcium and magnesium absorption in both animal and human studies.  The higher acidity draws out more minerals from food making them available to move from the gut into the bloodstream. This lead to more efficient absorption of calcium and increased bone density.

Interestingly, your body absorption of calcium only occurs when calcium intake is low or calcium requirement is high. This indicates the prebiotic, inulin, enables your body to absorb the amount of calcium it requires, not more than it needs.

WEIGHT LOSS & OBESITY

Howarth et al estimated that increasing fiber intake by 14 g per day was associated with a 10% decrease in energy intake and a 2 kg weight loss over about a 4-month period. This study was based on analysis of more than 50 other intervention studies. Fiber-rich food gives a sense of fullness (satiety), leading to less food being consumed. A nine week study using wheat dextrin conducted by the Chinese found that a significant decrease in caloric intake was seen from week 2 to the end of the 9 week study for those groups taking dextrin compared to controls.

Studies suggested microbiota in the gut may play a role in controlling obesity. Obese people have more firmicutes than bacteroidetes, while in lean people the bacteroidetes predominate. Tests with germ-free mice found that when these mice had “obese mice microbiota” transplanted into their gut, their total body fat significantly increase than colonization with a 'lean microbiota'. [Turnbaugh et al]

IMPROVE LAXATION

All fibers alleviate constipation. Insoluble fiber give bulk to stools, the water held by the fiber and increased bacterial mass from fermentation contributes to larger and softer stools thus increasing the ease of defecation.


Wednesday, November 26, 2014

What is in prebiotic?



Compounds in the non-digestible fiber of food provide the ‘fuel’ that stimulates the growth and/or activity of beneficial bacteria in the colon. The increased activity of these health-promoting bacteria results in a number of health-related benefits both directly by the bacteria themselves or indirectly by the organic acids they produce via fermentation.

Good bacteria use both resistant starch as well as non-starch polysaccharides compounds in prebiotic food such as cellulose, hemicellulose, inulin, galacto-oligosaccharide (GOS), fructooligosaccharides (FOS), xylooligosaccharides (XOS), polydextrose and   oligofructose. Arabinogalactan can be found in certain vegetables. Pectin, the soluble fiber in your apple also has prebiotic potential.

Researchers distinguish between long chain, short chain, and full spectrum prebiotics. Inulin is a long chain prebiotic fiber and is digested more slowly.  Long chain prebiotics contain 9 to 64 links per saccharide molecule, providing food for bacteria in the large intestine. Oligofructose can be digested more quickly. It is a short chain prebiotic, containing 2 to 8 links per saccharide molecule that is non-digestible only in the upper gut by humans. Full spectrum prebiotics is food that contains both long chain and short chain fiber.

Inulin is the most easily available commercially in the market. It has specific technological advantages, being soluble upon heating and bland in taste. It can be blended into a large number of different food products which retain their intrinsic flavor without alteration of texture and appearance. Inulin helps to provide body, good mouth-feel and appearance, thus it can be used as a fat replacer for the emerging sector of lower energy food products [Franck, 2002]. 

When we eat food with prebiotic compounds, this is what happens when the food travel from the mouth down the GI tract:
·         Mouth- Not broken down by enzymes, minimal bacterial breakdown
·         Stools- No prebiotic excretion
·         Stomach- Not broken down by stomach acids, no absorption
·         Small intestine- No enzymatic hydrolysis, no absorption
·         Colon- Probiotics such as Lactobacilli and Bifidobacteria ferments the prebiotic fibers for fuel, producing acids such as lactic acid, acetic acid, butyric acid etc., which inhibits or kill harmful microbes. The fermentation process does not produce toxicity, carcinogenicity or genotoxicity.

Next time you tuck into a fiber rich meal, you know that you are giving both yourself and your friendly tenants in the gut a healthy, good meal.