If you’re someone who likes to keep up with the latest in food and nutrition, you’ve undoubtedly heard or read about probiotics and prebiotics. You might know that they can aid digestion and reduce bloating, as touted in countless yogurt commercials on TV. But perhaps you didn’t know that they have numerous other potential health benefits. You might even be shocked to learn what probiotics really are: bacteria. Prebiotics, on the other hand, are the food that probiotics need to survive. While this knowledge might make some people squeamish at first, it is a necessary first step toward understanding the helpful role probiotics can play in the body. This article describes what probiotics and prebiotics are, how they can help you, and how they might in some cases be harmful — so that you can have a better idea whether adding them to your diet is right for you.
Probiotics are our friends
If the thought of bacteria coursing through your digestive system makes you squirm, take a deep breath and realize this: Some types of bacteria are good for us. We tend to hear much more about all of the harmful bacteria that can cause illness, such as Streptococcus pyogenes, which causes strep throat; or Escherichia coli, which can cause serious food poisoning. Often overlooked are all the good types of bacteria that help keep our bodies functioning properly and can even help ward off certain diseases.
The World Health Organization (WHO) defines probiotics as “living organisms which, when administered in adequate amounts, confer a health benefit on the host.” Microorganisms include bacteria, viruses, and yeasts — organisms that can only be seen with a microscope. While some varieties of yeast may confer a health benefit, the most common probiotics are certain types of bacteria.
Scientists estimate that about 500 different species of bacteria live in and on our bodies. In the typical human gut, there are about 100 trillion microorganisms belonging to these 500-odd species. The large intestine has the most bacteria due to its position as the “last stop” in the digestive system; here, bacteria break down certain molecules for energy that human digestive enzymes cannot. It takes several hours for digested food to travel the length of the large intestine, giving the bacteria there plenty of time to grow and thrive. The good news is that most of these microorganisms serve to protect us from harmful bacteria, as well as to aid in digestion, nutrient absorption, and immune function.
Think of probiotics as friendly bacteria. The word “probiotic” means “for life,” and as the name suggests, we all rely on these organisms to maintain optimum health.
Probiotics are nothing new; foods containing them have been around for thousands of years. Persian tradition attributes the prophet Abraham’s long life to drinking soured milk. The Romans described using fermented milk to treat intestinal gas. An early clinical account describes how Francis I of France, king during the 1500’s, suffered from diarrhea that was cured only when a doctor sent by the Ottoman sultan gave him yogurt. (Learn more about yogurt here.) Elie Metchnikoff, a scientist who won the Nobel Prize in Medicine in 1908, studied peasants in Bulgaria who lived longer than 100 years. He deduced that their good health and long lives were due to a microbe in a type of yogurt that they ate; he subsequently named this type of bacteria Lactobacillus bulgaricus. Fermented milk products, once rare outside the Middle East and southwestern Europe, have caught on in western Europe and the United States in the last century due to their introduction by immigrants and increasing knowledge of their health benefits.