The Forgotten Organ

[TiCam]

Weighing more than your heart, kidneys and pancreas combined, a 2-1/2 pound mass of microbes performs a function as VALUABLE as that of any other organ in the body.

Millions of bugs are writhing on your face. More than a trillion live in your mouth, multiplying so fast that you swallow trillions a day. From there on down your're hopelessly outnumbered, because the body contains 10 times more living, feeding microbes than it does human cells.

"It's been estimated that there are 100 trillion microbes in the human body and 10 trillion cells, so we like to joke that we're a minority in our own body," says Gary Huffnagle. And Huffnagle ought to know. He's a professor of internal medicine at the University of Michigan Health System in Ann Arbor.

They are our "normal flora," and they include "good" microbes that can help us and other microbes that can hurt us. Our good microbes help control bad ones, those inside us and those that invade. They also contribute to our health in ways that range from making the vitamins we need to preventing cancer.

Nowadays their roles are being superchanged by a revolution in "probiotics," beneficial bugs we can ingest through foods and supplements, according to Huffnagle, author of the recently published book, The Probiotics Revolution (Bantam, $40).

"What scientists have come to really appreciate in the last five years," he says "is that this mass of microbes that lives within us has the same function as an organ in our body. It's like a forgotten organ."

The average human body carries about 2 1/2 pounds of microbes, Huffnagle says--more mass than that of the heart, kidneys and pancreas combines.

"I call it an organ because all those microbes have DNA and make anzymes and make all sorts of chemicals, and as we eat, we also feed those microbes," he says. "Because they live right next to cells, they affect how cells in the body respond."

Probiotics include any live microorganisms that confer a beneficial health effect when ingested. The most familiar ones are the lactic-acid bacteria found in fermented dairy products such as yogurt and cheese.

"One thing they do is make lactic acid," says Huffnagle. "They love to live in acid. They can naturally survive in harsh conditions that most bacteria can't, which is why they like to live not only in the stomach but the upper part of the small intestine, where there's a lot of stomach acid and digestive enzymes."

Standard yogurt "starter cultures" in the United States are derived from bacteria that, once in our digestive system, can help maintain a healthy balance among the thousands of strains of bacteria that live there. What's new is that scientists are identifying more and more specific strains that, when eaten, confer specific health benefits.

Recent studies have shown, for example, that people taking certain probiotics:

-Have fewer gastrointestinal (GI) and respiratory illnesses.

-Are less susceptible to and recover faster from infectious diseases.

-Are more resistant to and recover faster from peptic ulcers.

-Maintain white blood cell counts in times of stress.

-Gain resistance to the viral gastroenteritis known as "stomach flu."

-Experience less severe colds.

-Have reduced oral bacteria that cause cavities and odor in the mouth.

On and on it goes, with recent studies showing potential benefits for probiotics across the medical field. One survey showed just five "probiotic" publications on the medical database Medicine before 1990, but nearly 800 from 2002 to 2004.

As more is discovered about probiotics, more food producers are adding specific strains to their products. Danon's Activia yogurt, for example, contains Bifidobacterium animalis DN-173010, believed to improve movement of nutrients through the intestines, especially for women and the elderly. The probiotic drink known as DanActive contains Lactobacillus casci DN-114001, shown to combat diarrhea, reduce the effect of stress on the immune system and increase resistance to infections. Stonyfield Farms' yogurt adds four probiotic strains to its products.

Four? Generally, "the more the better," says Huffnagle. "Someday the best probiotic will have many microbes together." Huffnagle suggests buying yogurts with the "live and active cultures" seal from the National Yogurt Association and avoiding those that simply say "made with active cultures," as they could have been heat-treated--killing the cultures--after fermentation.

When choosing supplements, he says, a good sign of quality control is that they list the genus, species and strain of bacteria. The genus Lactobacillus, for example, could have more than 20 species, and each of these could have hundreds of strains.

"If they say it contains Lactobacillus but don't say the species, then walk away," he says.

And they should clearly state the number of colony forming units (one CFU is 1 billion microbes) -- and buyer be suspicious if the label just gives weight of bacteria in grams or miligrams. "Throw that out," Huffnagle says. "It's irrelevant. You want to know how many are alive."

For general health, you want to consume at least 5 billion probiotic microbes per day, he says, which isn't difficult. A 6- to 8-ounce serving of yogurt typically contains 6 billion to 20 billion. A 2-ounce slice of Emmenthaler cheese is estimated to contain 40 billion, although Emmenthaler is a more outstanding probiotic than most cheeses.

Labeling is still uneven, and research and development has a long way to go as science learns more about the care and feeding of the forgotten organ.

"The largest proportion of the nervous system outside the brain is found in the gut," Huffnagle says, which gives an added meaning to the word "stomach-ache." There are more neurotransmitters made there than any place in the body and we're realizing that bacteria can respond to these neurotransmitters. The gut may be a central sensor for the whole immune system."

Huffnagle's lab found out, for example, that changing the types of microbes that live in the gut actually changes the way that the lungs respond to alergens.

What's more, they found that microbes are involved in the all-important anti-inflammatory process. Inflammation is the immune system's (often excessive) response to all kinds of chemical and biological trigggers. And inflammation is the immune system's (often excessively) response to all kinds of chemical and biological triggers. And inflammation can underlie problems ranging from allergic reactions to heart disease, from digestive disorders to cancer.

"When the microbes eat and digest things, they produce chemicals as waste products, and many of them are anti-inflammatory signals for the immune system to be more tolerant," Huffnagle says. "It's almost like the microbes are making their own aspirin."

Changes in gut microbes are also associated with colon cancer. "Everything you eat, no matter how healthy, has some carcinogens," he says. "The good news is that microbes in the GI tract are awesome in breaking those down to something that is not carcinogenic."

Huffnagle believes that our failure to care for our microbes is a major factor in the rise of a number of chronic diseases. One reason for that failure has been the wanton use of antibiotics, which kill the good bugs along with the bad. Another is diet, which he says since the early 1980s has included more refined foods lacking soluble fiber and has replaced spices, a rich source of antioxidants, with flavorings.

"There was a radical increase in chronic diseases--asthma, inflammatory bowel disease, autoimmune diseases--beginning around the 1980s, he says.

"Things that happen in the gut don't necessarily stay in the gut. If we actually take care of the microbes within us, it will improve our health tremendously."