The Good Bugs!
Probiotics are live bacteria and yeasts that are good for your health. They are extremely complicated, and have been the subject of intense research for the last 20 years, as they impact on virtually all diseases.
The body is full of bacteria, both externally and internally, both good and bad. The average healthy human consists of micro-organsisms and human cells, and is made up of 90% micro-organisms and 10% human cells. (see footnote for greater detail)
Stress, interactions with other people, poor diet, change of diet, antibiotics, prescribed medicines, antibacterial washes, travel, and alcohol can all lead to changes in the micro-organisms on and in our body. This in turn will cause changes in our body, sometimes good, sometimes bad.
Probiotics can be used to prevent or treat many conditions. They have been known to help eczema, boost immunity, reduce allergies, improve irritable bowel syndrome or inflammatory bowel disease, improve cholesterol levels, treat diarrhoea and improve urinary and vaginal health.
In humans, virtually any disease from brain cancer to arthritis will cause a distinct difference in the makeup of the bowel bacteria. Although research is currently ongoing, so far the practical applications are limited to the conditions mentioned above.
Interesting studies have been done with mice, looking specifically at the healthy bugs in the bowel. Transferring the healthy bugs from diabetic mice to healthy mice caused diabetes in the healthy mice. Transferring healthy bugs from the bowel of healthy mice to diabetic mice appeared to normalise the diabetic mice (diabetes seemed to stop). Transferring healthy bugs from obese mice to normal mice caused obesity in the normal mice, and the reverse also happened, transferring healthy bugs from the bowel of normal mice to obese mice caused normalisation of the weight of the previously obese mice.
The DNA in the probiotics that live in the body talk to the body's own DNA and they both turn various genes on and off in the body.
It appears the importance of a healthy gut bacteria cannot be over emphasised.
Fibrous foods (especially raw onion and raw garlic) feed the healthy bugs in the bowel and are called prebiotics - essentially probiotic food.
Some interesting articles:
Footnote: The original calculations that came up with 90% micro-organisms and 10% human were done in the 1970's and by today's standard were quite roughly done. They assumed an alimentary tract volume of 1000ml and assumed the concentration of micro-organisms to be constant throughout. Today it is estimated that the vast majority of the micro-organisms occur in the bowel, and it has an effective volume of around 400ml. Taking that into account alters the equation radically to around 1:1. However, the normal definition of a cell includes a nucleus, and the majority of "cells" counted in a human consist of red blood cells, which in fact do not have a nucleus and have been described as "bags full of hemoglobin". If you exclude the red blood "cells", then the ratio of micro-organisms to human cells stays at 90% to 10%. For a more complete discussion see