Chapter 1
Getting a Handle on the True Nature of Bacteria
In This Chapter
Exploring the discovery of bacteria and their role in health
Looking at the connection between bacteria and brain development
Investigating bacteriaās role in mood and anxiety
The United States, the world leader in so many other areas of health and medical science, is considered an āemerging marketā in the development and use of probiotics; such supplements are far more popular in Europe and Asia, and probiotic-rich foods (see Chapter 11) are staples in many cultures around the globe.
Interestingly, according to the National Health Interview Survey conducted by the National Institutes of Healthās National Center for Complementary and Alternative Medicine (http://nccam.nih.gov
As in other countries, yogurt manufacturers in the United States have long touted the benefits of live cultures of bacteria in their products. More recently, companies like Dannon have begun aggressively marketing yogurt and its friendly bacteria as a way to regulate your digestive system ā and they back up their claims by financing or conducting clinical studies.
The National Center for Complementary and Alternative Medicine also has made probiotic research a high priority for funding projects. The center supports research on using probiotics to alleviate or prevent various gastrointestinal disorders in infants and children; treating and preventing antibiotic-related diarrhea (see Chapter 4); and improving the efficacy of flu vaccines.
Government and privately funded research is turning up lots of evidence that probiotics can do more than regulate your digestive system. I provide information on various health applications for specific probiotic strains throughout this book. But researchers also are uncovering fascinating links between the bacteria in your digestive system and your brainās development, as well as mental health issues like anxiety and depression, which I discuss later in this chapter. First, though, the next section provides a brief overview of the theories and discoveries about bacteriaās role in sickness and health.
Exploring the History of Bacteria Theories and Practices
Centuries before the invention of the microscope enabled researchers to observe living organisms that are invisible to the naked eye, some scientists theorized that tiny creatures spread disease among animals and humans. Ancient Hindu texts, for example, refer to living agents as causing disease. In 36 BC Marcus Terentius Varro warned against building homes and farms near swamps because such areas breed ācertain minute creatures, which cannot be seen by the eyes, which enter the body through the mouth and nose and there cause serious diseases.ā
Even so, conventional wisdom discounted the idea that organisms like bacteria, or germs, caused illness. The prevalent theory was that disease generated spontaneously. Even Anton van Leeuwenhoek, considered the father of microbiology, didnāt connect the organisms he saw under his microscope with disease. And the idea that human contact could transmit harmful microorganisms met with massive resistance among the medical and scientific communities.
In the following sections, I provide a brief overview of how the germ theory of disease developed and the history of using probiotics, or good bacteria, to promote good health.
Understanding germ theory
Although it forms the basis of medical treatment and hygiene practices today, germ theory ā the idea that microorganisms are responsible for causing and spreading illness ā was quite controversial for centuries. Before the invention of the microscope, most people (including most doctors and scientists) believed that disease either arose spontaneously or was spread through ābad air,ā or miasma.
Ignaz Semmelweis, a Hungarian obstetrician working at a Vienna hospital in 1847, noticed that when doctors and medical students attended births, new mothers were far more likely to die of puerperal fever, commonly known as childbed fever, than women who delivered their babies at home with the aid of a midwife. Semmelweis observed that doctors and medical students at the hospital often delivered babies right after performing autopsies, and he insisted that doctors wash their hands in a chlorinated solution before examining pregnant women. This elementary technique lowered the childbed fever death rate at the hospital from nearly 1 in 5 to about 1 in 50.
English physician John Snow added evidence supporting the germ theory when he traced the origins of a cholera outbreak in London in the 1850s. Snow noticed that the homes of people affected by the outbreak all got their water from the same pump, and he identified that water as the mechanism for spreading the disease.
In the 1860s, Louis Pasteur conducted experiments that proved that living organisms in freshly boiled broth came from outside the broth rather than spontaneously generating within it. A decade later, Joseph Lister (for whom the Listerine brand mouthwash is named) developed procedures for sterilizing surgical instruments and wounds in hospitals.
Although some physicians and scientists proposed some version of germ theory for centuries, the idea didnāt gain wide acceptance until the late 19th century, when Robert Koch demonstrated that anthrax was caused by specific bacteria. Since then, germ theory has led to development of antibiotics and hygiene standards, and it remains a foundational element of both modern medicine and microbiology.
Discovering probioticsā benefits
For more than a century, germ theory (see...
