Probiotics- Using bacteria for improving health
Ajmila Islam
Research Assistant
University of Minnesota, USA
Contact: isla0010@tc.umn.edu

More or less people are familiar with the term “Bacteria”, which is responsible for different diseases of human. However, these bacteria could bring a health promoting benefit of human is not yet known to the people. There is currently growing interest in certain bacterial strains that have been suggested or shown to provide specific health benefit when consumed as food supplements or as food components. The concept of ingesting bacteria for the purpose of improving one’s intestinal health and general well being can be traced back in the beginning of the 20th century. This practice is now referred to as “Probiotics” and is the subject of intense scientific research directed toward obtaining effective probiotic bacteria and establishing their health benefits.

How do probiotics work?
The actual mechanisms of probiotics have not yet been fully elucidated. Based on a number of in vivo and in vitro studies, it has been speculated that the probiotics i.e. these “good bacteria” benefit the host by several ways-

1) The intestinal pathogens could adhere to the gut wall if they are to colonize the gut and produce disease. Probiotics strains have the ability to adhere to the epithelial wall and thus compete with pathogens for adhesion receptors, ultimately prevent disease.
2) Probiotics strains are thought to stimulate the macrophage activity and natural killer cell activity, thus enhance immunity.
3) They also might have the effect of reducing number of viable pathogenic strains or of affecting the metabolism or toxin production of the intestinal bacteria.

Which bugs work?
The bacteria most commonly used as probiotics fall under the general heading of lactic acid bacteria. These bacteria feed on sugars and produce lactic acid, which is part of the reason they are so useful in the food industry: by generating acid and lowering the amount of sugar, they make food like yogurt, cheese, sauerkraut inhospitable environments for disease-causing organisms. The bacterial strains tested most often belong to the Lactobacillus and Bifidobacterium genera.

Beneficial effects of probiotics:
Documented examples of the beneficial effects of the probiotics include their use in the treatment of various types of diarrhoea, the alleviation of lactose intolerance, the relief of constipation, and the general balancing and stabilization of intestinal integrity.

More recent claims for some strains include immune enhancing and vaccine-adjuvant effects as well as an ability to lower serum cholesterol levels to affect cancer-related parameters. Although there are claims for beneficial effects of probiotics in stimulating immune response, ulcerative colitis, cancer and heart disease they will not be dealt with here because the evidence is almost exclusively from laboratory animals and this is not always conclusive. What are worth describing are examples where the evidence for a positive beneficial effect in human is very good.

Studies on the treatment of acute infant diarrhoea have been successfully carried out with Lactobaccilus GC, and on the treatment of rotavirus diarrhoea using Bifidobacterium bifidum has been found to be successful. Traveller’s diarrhoea has also been successfully prevented in a study using probiotic mixture L. acidophilus, B. bifidum, S. themophilus and L. bulgaricus. Numerous probiotic agents have been studied for the management of diarrhoeal disease in pediatric patients, in particular, the prevention and management of acute viral disease, the treatment of recurrent C. difficile diarrhoea, as well as the control of antibiotic-associated diarrhoea seem to be the areas of significant potential benefit. Several competent clinical studies appear to suggest that the specific probiotic bacteria can alleviate or prevent diverse intestinal diarrhoea-including disorders such as lactose indigestion and cause prophylaxis of intestinal infection.

Future perspectives:
While there is no doubt that gut flora can protect the host against disease, we lack good evidence from controlled clinical trials that the bacteria are currently being used as probiotics are those which are responsible for the beneficial effects of the gut flora. What we needed at this moment is more information on the way that probiotic supplements act. When we have this sort of information it may be possible to improve the strains by genetic manipulation, which would bring together the ability to survive in the gut with the ability to produce the metabolites responsible for the probiotic effects.

Researchers and companies are competing to show that their particular bacteria strain works best. Some are placing their bets on combinations. Their constant works are to answer a question, “Is probiotic a myth or a mystery?”