Benefits of Probiotics
What are probiotics?
World Health Organisation defines Probiotics as "Live microorganisms which when administered in adequate amounts confer a health benefit on the host". Probiotics are generally fermented foods like yoghurt and dairy products fortified with active live cultures of beneficial microorganisms. Generally Lactic Acid Bacteria(LAB) and Bifidobacteria are popular probiotic cultures. However some yeasts and bacilli are also used.

Advent of Probiotics:
Russian scientist and Nobel laureate Eli MetchinKoff observed that some rural populations in Bulgaria and the Russian steppes had an increased life span. Their staple diet was milk fermented by lactic-acid bacteria. With these observations Metchnikoff suggested that ingestion of fermented milk resulted in the colonization of the intestine with lactic-acid bacteria which lowers the intestinal pH and reduces the population of proteolytic bacteria like clostridium which break down proteins and in the procedure release some toxic substances. Metchnikoff himself benifited by consuming milk fermented with the bacteria which he named "Bulgarian Bacillus".
Later Henry Tissire isolated Bacillus bifidus which was later renamed to the genus Bifidobacterium from breast fed infants. Clinical observation revealed that Bifidobacterium enhanced the treatment of diarrhea in infants.
In the year 1935 trials with certain strains of Lactobacillus acidophilus showed that this organism was effective in treatment of chronic constipation.
The term Probiotics was first suggested by Kollath in 1953. In 1989 Roy Fuller defined a probiotic as "A live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance". Examples of popular probiotic microorganisms are Lactobcillus rhamnosus, and L.casei

Benefits of Probiotics
Earlier it was thought that probiotics only reduced the growth of intestinal pathogens and helped in striking a microbial balance in the intestine. Recent research has suggested that, probiotics, can be helpful in chronic intestinal inflammatory diseases, play a role in prevention and treatment of allergic reactions, certain infectious diarrhea and urogenital infections.
Experiments at molecular level are analyzing the role of Lactobacillus as, an anti-cancer agent and a biomedicine in some cases of traveler's diarrhea, pediatric diarrhea, and irritable bowel syndrome. However the benefits are strain specific and vary among different strains of Lactobacillus. Some scientists even consider it a an alternative form of medicine.
Clinical trials conducted with probiotics show that they do have certain beneficial effects on health. However more research is required.

Benefits of probiotics on gastro intestinal relaled problems:

Infectious diarrhoea :

Certain probiotics help in prevention of gastroenteric infections. Consumption of probiotics, decrease the duration of illness and also help in bringing down the frequency of stools. Probiotics also help in reducing the severity of rotaviral diarrhea in children.

Antibiotic associated diarrheas

One of the side effects of prolonged antibiotic intake is imbalance in the intestinal flora. This alteration can also result in over population of certain like harmful bacteria Clostridium difficile.
Sometimes a change in the intestinal flora leads to problems in carbohydrate metabolism and fat absorption causing osmotic diarrhea. In such cases probiotics can help in reducing the severity of AAD. However the efficiency depends on strain and the dosage of the probiotic.

Role in prevention of colon cancer

Certain LAB strains have found to prevent colon cancer in mice while human trials have shown that these strains can reduce the activity of Beta-glucurinidase which has the ability to produce carcinogens in the digestive system. Certain strains of LAB also have the ability to bind with carcinogenic substances like heterocyclic amines seen in cooked meat.

Lowering cholesterol and blood pressure
Animal experiments have shown that some LAB strains breakdown bile thus preventing its re-absorption in the gut. This helps in reducing cholesterol levels as otherwise the re-absorbed bile is taken up by blood in the form of cholesterol. How far this theory is true in hyperlipidemic cases is still being researched.
Some strains of LAB are able to produce ACE inhibitors as a byproduct of fermentation which may help in reducing blood pressure.

Role of probiotics in enhancing immunity:

Research shows that certain LAB have profound beneficial effects on the immune system. Clinical studies indicate that probiotics can reduce the incidence dental and respiratory tract infections in children. Certain strains of LAB seem to enhance the functioning of the immune system by the following methods
• Prevent colonization of pathogens by competing for growth.
• Enhance the production of IgA producing B-cells.
• Enhance the production of phagocytic T cells and Natural killer cells.

Irritable Bowl syndrome

Clinical trials have shown that Bacillus.infantis and Lactobacillus plantarum help to reduce the symptoms associated with Irritable bowl syndrome.

Reducing inflammation

LAB seems to regulate the functions of cytokines which in turn reduce the intensity of allergic and inflammatory reactions. They have been found to reduce the frequency of irritable bowel syndrome. Researchers believe that this could be due to desensitization of T-cells to allergens, though this theory is yet to be proved.

Though Probiotics have gained popularity in the recent years and many clinical trials have proved its benefits, it is also suggested that they can lead to infection in immunocompromised individuals. Lot of Research is still going on in this field.

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