March 6, 2006
A University of Michigan Health Minute update on important health issues.
Probiotic microbes could be a key to good health
ANN ARBOR, MI – Medical researchers are finding that one of the keys to good health could be living in our guts – specifically, in the world of microbes that live in our digestive tracts.
Researchers are discovering that this “good” bacteria helps not only to stimulate digestive health, but may stimulate a healthy immune system. These probiotic bacteria may even be a key to understanding obesity. Gary Huffnagle, Ph.D., of the University of Michigan Health System, is one of the country’s leading researchers into the world of probiotics.
“Current research into this microbial world is uncovering many benefits to eating a diet rich in probiotic nutrients,” Huffnagle says.
He says that until we are born, we are completely sterile of microbes. Once outside the womb, we are bombarded by microbes and soon we have 10 times more microbes in our body than the number of cells that make up the human body.
Good microbes and bad microbes
It is the bad microbes that cause disease. Good microbes work with the body’s immune system to keep the bad microbes at bay by crowding them out. In the symbiotic relationship between good and bad microbes, recent research has uncovered the importance of these good microbes.
“The good microbes – and this is where probiotics come in – keep the bad microbes in small numbers. But they also stimulate the immune system and improve our digestive function. That’s the subject of research that has been going on for years,” Huffnagle says.
Probiotics are bacteria that we eat and they’re good for our health. They are found in a number of foods that are readily available in the supermarket, and they taste good. You can support probiotic growth by increasing the amount of cultured dairy products you eat, such as cheeses and yogurt, and the foods that encourage probiotics from these dairy products to multiply even further: spices, tea, red wine, berries, apples and beans.
Huffnagle says that most of these good microbes exist within our body in the digestive tract, with the largest number occurring in the small and large intestines.
“It’s the job of these good microbes to stimulate our immune system, and the other job they do is to stimulate good digestive health,” he says.
Historically, until about five years ago, probiotics were considered only within the realm of complementary and alternative medicine. As our understanding of the immune system and how it works has expanded, so has the understanding of the importance of probiotics and probiotic microbes in the gastrointestinal track in regulating the immune system.
“Today, the world of probiotics is emerging on the cutting-edge of mainstream medicine,” Huffnagle says.
Antibiotics and probiotics
We inadvertently kill off the good microbes in our body with antibiotics. Since antibiotics are necessary for killing the bad microbes that cause some diseases, they are important for helping to keep people healthy. However, the side effect to taking antibiotics is the elimination of the good microbes within our body along with the bad ones.
“We’re now finding that eliminating all the good microbes from our body results in a weaker immune system, which we believe is leading to problems such as increased incidence of chronic disease, including allergies like asthma,” Huffnagle says. “Once you take antibiotics as your physician prescribed, follow it with some form of probiotic supplement to get the microflora in your gut back to where it should be. Your recovery and your health will be much greater.”
Since probiotic microbes do not cause disease, there’s no such thing as having too much of them. And Huffnagle points out that foods rich in probiotics taste good.
New products are coming on the market to specifically support probiotic health. Typically, these are fermented dairy products in which companies have added one or two types of highly concentrated probiotic bacteria.
At the U-M Health System, Huffnagle’s research focuses on one of the greatest unknown questions about probiotics: How do they work?
“We are examining how microbes in the gut communicate with the immune system. Many diseases have an immunologic basis, so we want to understand the good communication that goes on between the microbes and the immune system,” he says.
Probiotics and obesity
Another emerging topic of research examines a possible link between probiotics and obesity, and a number of researchers around the country are starting to look at this connection.
“We should have known that probiotics and the gut microflora play a role in metabolism – it’s a connection that’s been known in the agriculture industry for years,” Huffnagle says.
Agriculture experts quickly noted that sick livestock gained weight when dosed with antibiotics, leading to the industry practice of routinely rotating various low-dose antibiotics in livestock feed. Huffnagle says the antibiotics actually change the metabolism of the animals, creating something called “enhanced feed efficiency” – an improved ability to retain fat.
“We take the antibiotics to recover from a microbial illness, but the trade-off is that fat we eat may be staying with us instead of being metabolized and converted to energy,” Huffnagle says.
He says that antibiotics are important for fighting disease and should always be taken according to physician recommendations. However, making a point of eating dairy products rich in probiotic microbes and foods that provide nutrition for the probiotics will help these microbes prevent immune system and metabolic problems.
For more information, visit these Web sites:
Food & Agriculture Organization of the United Nations
U.S. Probiotics: Products with probiotics
Yale-New Haven Health: Probiotics
Nature: Probiotics get a boost
Written by Mary Beth Reilly
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