The friendly bacteria

Bacteria are commonly considered as harmful agents for our body. But not all bacteria do cause diseases. There are some good bacteria known as probiotic bacteria when administered in adequate amount confer a health benefit on the host.
These good bacteria are normally consumed in fermented food products such as yogurts or yogurts drinks. In recent years, probiotic bacteria are also available in supplements as capsules, sachet, liquid and chewable. These bacteria are well known for their role in fermenting of host’s indigestible carbohydrates and extracting energy. There are many different strains of probiotics, but the most common strains are Lactobacillus and Bifidobacterium.
Probiotic bacteria live on host’s non-digestible carbohydrates. They are not only digest and extract energy for themselves but also supply energy and other micro nutrients including vitamins to the host. Without these bacteria there is about 30% more calories required to maintain normal body mass.
There is growing concern that sedentary lifestyle and dietary change, most notably the high-fat/high-sugar, can change the genetic composition and metabolic activity of our resident microorganisms. In the developed world such diet-induced rapid changes of our gut-microbial communities are now suspected of contributing to growing epidemics of chronic illness such as obesity, diabetes, inflammatory bowel disease and cancer.
Experiment has been shown that there was a substantial difference between gut bacteria composition of young twins when one was obese and the other slim. When faecal microbes of these twins are transplanted into microbes-free mice, the mice were shown to develop a similar obesity pattern of their human counterpart that is the mice with the microbes from the obese twins became obese too.
In recent year, study has shown that probiotic bacteria can improve the moods and alleviate symptoms like stress, anxiety and depression in both animal and human subjects. These microbial induce brain modulatory mechanisms are believed to be due to their direct action on the peripheral nerves as well as release of chemicals which interacts and regulates our physiological mechanisms. Spermidine, a polyamine, produce by some probiotic bacteria, has been shown experimentally to have beneficial effects on ageing associated memory impairment in human.
There are lot of evidence which suggest that probiotic bacteria not only control host’s metabolism but also plays an essential role in regulating host’s immune system as well as influencing development and maturation of organs and maintain their functionality. These bacteria are our real friend.

The writer is a Senior Lecturer in Human Biology, School of Science & Engineering, Teesside University and Honorary Lecturer, Institute of Ophthalmology, University College London. E-mail: [email protected]