By Dr. Harold Gunatillake – Health Writer
Our alimentary system or the bowel is inhabited by millions of good and bad bacteria. The good micro-organisms may help with digestion and offer protection from harmful bacteria, just as the existing “good” bacteria in your body already do to improve the intestinal microbial balance.
According to the adopted definition by FAO/WHO probiotics are: “Live micro organisms which when administered in adequate amounts confer a health benefit on the host. The most common types of bacteria used as probiotics are lactic acid bacteria and bifidobacteria, and certain yeasts and other bacilli may also be helpful”. Probiotics are available as nutritional supplement which can be added to your diet or found in foods such as yoghurt, fermented and unfermented milk, miso and some juices and soy drinks.
Probiotics may help and there is encouraging evidence that their beneficial effects on the following diseases:
• Treat diarrhoea, especially following treatment with certain antibiotics
• Prevent and treat vaginal yeast infections and urinary tract infections
• Treat irritable bowel syndrome (IBS)
• Reduce bladder cancer recurrence
• Prevent colon cancer
• Lowering cholesterol
• Lowering high blood pressure
• Improving immune function and prevent infections
• Reduce inflammation
• Improving mineral absorption
• Speed treatment of certain intestinal infections
• Prevent and treat eczema in children
• Prevent or reduce the severity of colds and flu
In addition, some believe that probiotic supplements may improve general health. There are no side effects taking probiotics, but it is a good idea to check with your physician that they will not interfere with your medication.
History of Probiotics
The idea of the positive role played by certain bacteria in the bowels was first introduced by Russian scientist and Nobel laureate Eli Metchnikoff, during the early 20th century. He suggested that the gut friendly bacterial inhabitants (flora) can destroy the harmful microbes, thus preventing diseases. He further said that the aging process results from the activity of putrefactive microbes producing toxic substances in the bowel.
Toxin producing bacteria
Bacteria such as clostridia, forming a part of the gut flora produce toxins such as indols and ammonia from the digestion of proteins in foods. According to Metchnikoff these toxins cause “intestinal auto-intoxication”, which would be responsible for the physical changes as one ages.
He also found that milk fermented with lactic acid bacteria inhibited the bacteria that caused toxins because of the low pH produced by the fermentation of lactose. This was the reason attributed to Bulgarians and Russians who lived largely on milk fermented by lactic acid bacteria exceptionally lived longer. These beneficial bacteria found in the gut more likely produces the desired effect in the gut.
In 1935 certain strains of Lactobacillus acidophilus were found to be very active when implanted in the human digestive system. These organisms were used for the relief of constipation. It was a scientist by the name of Kollath who introduced the term “Probiotics”. He pointed out that probiotics stimulated the growth of other micro organisms. In 1989 Roy Fuller suggested a definition of probiotics which has been widely used: “A live microbial feed supplement which beneficially affects the host animal by improving its intestinal microbial balance”.
Lactic acid bacteria actively converts lactose into lactic acid, ingestion of certain active strains may help lactose intolerant individuals tolerate more lactose than what they would have otherwise.
Health benefits of certain strains of Lacto-Bacillus
Prevention of colon cancer
In laboratory trials some strains of Lactobacillus have demonstrated anti-cancer effects thought to be due to their ability to bind with heterocyclic amines, which are carcinogenic substances formed in cooked meat.
Animal studies have demonstrated the efficacy of a range of lacto-bacillus to be able to lower serum cholesterol levels, presumably by breaking down bile in the gut, thus inhibiting its re absorption, which enters the portal blood stream as cholesterol. Human trials have shown that dairy foods fermented with lacto-bacillus can produce reduction in the total and LDL cholesterol levels.
Lowering of blood pressure
Some clinical trials have shown that consumption of milk fermented with strains of lacto-bacillus may result in modest reduction in blood pressure.
Improve immune functions
Lacto-bacillus may protect against pathogens by means of competitive inhibition (i.e. by competing for growth), and there is evidence to show that they may improve immune function by increasing the number of IgA- producing plasma cells, increasing phagocytosis (killing pathogens by certain white blood cells), as well as increasing the T lymphocytes. There are many other health benefits, such as decreasing the incidence or respiratory tract infections, dental caries in children, treatment and prevention of acute diarrhea and many others detailed earlier.
Yoghurt and other supplements
The manufacturers of probiotic yoghurt claim their products can help relieve digestive irregularities and boosts the immune system. Probiotic expert Professor Bob Rastall, head of Food and Nutritional Sciences at the University of Reading in the UK, firmly believes probiotics are useful for health.
He stresses that probiotics are considered by some as “functional foods” — products which have ingredients or components in them that can improve health or reduce disease risk in humans. “But they’re not drugs — they don’t prevent or cure disease,” he warns.