(The Boston Globe, November 21, 2000)
The idea that billions of bacteria are swimming around in our guts can make hygiene-conscious Americans uncomfortable. Don't we use anti-bacterial soap to get rid of creatures like that?
But it's true: researchers estimate that these microbes outnumber the cells in our bodies by a ratio of 10-to-1. And, while some do make us sick, a lot more actually help us digest everything from milk to nuts, or boost our immune systems by repelling the bad bugs that ride in on our food. Now, lowly bacteria is finally getting some respect in US health food stores and supermarkets as a flood of medical research suggests that deliberately ingesting certain bacteria may be good for us.
Since 1998, major companies have launched a wave of bacteria-containing products such as Probiotica, a lemon-flavored pill that is supposed to "promote digestive health" by ferrying billions of Lactobacillus reuteri bugs to your gut.
"Every person has his or her own balance of bacteria. It's been an ancient tradition that, if you can supplement your balance with more good bacteria, this will be healthier for you," explained Dr. Sherwood Gorbach, a professor of community health and medicine at Tufts University who has pioneered research into helpful bacteria, known as probiotics.
Most Americans have never even heard of "probiotics," mainly strains of bacteria used in the fermentation process. While people in Europe, Asia, and the Middle East long have consumed fermented dairy products such as yogurt and kefir for the live bacteria cultures they contain, Americans eat less yogurt than residents of any other developed country.
"We're not just creating a new product, we're creating a whole new category," said Anna Moses of the Dannon Co., which is test-marketing a probiotic milk drink called Actimel in Denver. "Probiotics are a secret the US population has yet to learn."
As the probiotic drinks, tablets, powders and other supplements come on the market, however, they are winning converts, especially among people who are extremely health conscious. "They're convenient. I drink one with my hormones every morning," said Denver dietician Mary Lee Chin, 51, who drinks a daily 3.3-ounce bottle of Actimel. The drink has eased her lactose intolerance and she believes it has also kept her from getting sick despite a high-stress lifestyle.
Like vitamins and herbal products, most probiotics are currently sold as dietary supplements, which means that, by law, their labels can't mention specific health claims, even if there are studies backing them up. But, unlike many of today's popular alternative health products, probiotics have earned cautious support from even prominent practitioners of conventional medicine.
Dr. W. Allan Walker, chief of Harvard's Nutrition Division, said: "I think the use of probiotics is a very positive thing in society. There are so many antibiotic-resistant organisms now, we need to look at different ways" to combat harmful microbes.
The best-studied probiotic strain, called Lactobacillus GG, or LGG, appears to prevent and treat rotavirus diarrhea, a potentially serious intestinal upset that afflicts 80 percent of children by age 5.
In a European trial of nearly 300 infants and toddlers with acute diarrhea, those given oral rehydration solution containing LGG recovered about 16 hours sooner than did children given rehydration alone. Other studies suggest that at least five different bacteria either attack the microbes that cause illnesses such as food poisoning, boost the number of immune cells, or perform some other useful digestive or immune service.
At a minimum, the helpful bacteria don't seem to do any harm unless a person has a seriously depressed immune system, said pediatric infectious disease expert Dr. Larry K. Pickering, director of the Center for Pediatric Research at Children's Hospital of the Kings Daughters in Norfolk, Va. "The field is still in the data-gathering phase . . . but the future potentially looks very promising," Pickering said.
Because probiotics are largely unregulated, however, consumers have to beware of what they're getting. Researchers have been encouraged by the entrance of big companies such as ConAgra into the business partly because it promises greater quality control.
"A lot of the probiotic cocktails that you get at [the health food stores] are all dead" and useless, said Dr. Athos Bousvaros, a pediatric gastroenterologist at Children's Hospital in Boston. "There's a lot of snake oil to this."
Moreover, not every strain of bacteria can withstand the heat and acid of the gastrointestinal tract. Lactobacillus acidophilus, the main ingredient in many products sold as probiotics in health food stores, didn't survive digestion in studies by Tufts' Gorbach. Most commercially available yogurts don't qualify either, because the two starter cultures they're made with, Lactobacillus bulgaricus and Streptococcus thermophilus, don't survive in high enough quantities in the gastrointestinal tract.
Yogurt is great for people with lactose intolerance because the live cultures predigest lactose. But most yogurts don't provide additional health benefits beyond that and their nutritional value, Gorbach noted.
But the makers of at least two brands of yogurt - Stonyfield Farm and Horizon Organic - add additional live cultures that have shown probiotic potential. Consumers should make sure the product label has both an expiration date and a guarantee that at least 5 billion organisms will survive, according to Barry Goldin, director of the biochemistry and microbiology lab at Tufts. "You'll eliminate many with those criteria."
Ironically, today's probiotic movement is a return to a health care strategy that is almost a century old. The strains of bacteria involved in fermenting milk or alcohol essentially digest the material, harvesting its energy without oxygen to aid the breakdown process.
Back in 1907, Nobel Laureate Elie Metchnikoff recognized the potential health benefits of these bacteria, writing, "A reader who has little knowledge of such matters may be surprised by my recommendation to absorb large quantities of microbes, as the general belief is that microbes are all harmful. This belief, however, is erroneous. There are many useful microbes."
But it took Gorbach and Goldin of Tufts to jump-start the science of probiotics in the early 1980s. With funding from the dairy industry, the pair spent two years painstakingly searching through stool samples donated by friends and colleagues for a bacterial strain that would meet certain qualifications originally outlined by Metchnikoff: It had to be able to survive the brutal journey through the stomach's acid, attach itself to the lining of the large intestine, and multiply there. Also, it had to be able to kill bad bacteria.
In 1985, Gorbach and Goldin found the bacteria LGG (named with their initials), which met the requirements. The two patented the strain and licensed it to a Finnish company, Valio, which in turn licenses LGG exclusively in the United States to ConAgra. It's sold in capsule form under the name Culturelle, available at CVS stores and on the Internet.
LGG has proven to be something of an intestinal health bonanza. In addition to its helpfulness in easing diarrhea, it may prevent certain types of the condition in the first place, researchers say, especially diarrhea triggered by taking antibiotics. LGG could even help in certain disorders outside of the gastrointestinal tract, such as a food allergy: A small Finnish study found that LGG and bifidobacteria reduced the severity of atopic eczema, a skin condition associated with milk allergy, in infants who were switched from breast milk to formula.
But LGG isn't the only probiotic game in town. In studies conducted by Dannon, a strain called Lactobacillus casei boosted the immune response in healthy volunteers following receipt of influenza and tetanus vaccines. And a study in French day care children suggested that it, too, may reduce diarrhea.
Likewise, Lactobacillus reuteri, the featured ingredient of Stonyfield Farm yogurt and McNeil's chewable Probiotica tablets, may boost the immune system. L. reuteri produces a substance called reuterin, which kills harmful bacteria such as salmonella, E. coli, Staphylococcus, and the yeast candida.
Although no studies have looked at whether long-term use of probiotics is beneficial for healthy people, that is clearly the target audience. The products' boasts - "All-natural probiotic supplement" or helps "maintain a healthy intestinal tract" - are most likely to reach people who are quite sophisiticated about maintaining their health. But Tufts' Goldin, despite his role in pioneering probiotics, isn't so sure Americans will flock to these products the way that Europeans have.
"Much of America still looks at yogurt as something odd," he said, and it would take a huge education campaign to convince people that some bacteria is good.
Indeed, poor sales forced the discontinuation last month of Nestles' probiotic product, a powder called LC1 that contained the strain Lactobacillus johnsonii. It was on the market just eight months. But product manager Pat Pipkin attributes the low sales to the product's high cost - $32.99 for 30 packets - and to its powder format - the idea was to sprinkle it in food or cold drinks - rather than to a failure of the concept of probiotics. LC1 has sold well in Europe since 1994. And other probiotics are doing better than LC1.
"Our business is growing substantially. It's certainly trending in the right direction," Culturelle sales manager John Miedema said.
In the future, ConAgra is likely to launch new food products such as cheeses that will contain LGG. Actimel now sells at the rate of nearly 3 million bottles a day in about 15 countries. Sales have been so good in Denver since it was launched there in July 1999 that Dannon plans to bring it to other US cities, possibly including Boston, in 2001, company spokeswoman Anna Moses said.
Metchnikoff, whose book, "The Prolongation of Life," preached the life-extending qualities of fermented milk nearly a century ago, would be pleased that his ideas are thriving in the 21st century. ###
Copyright © Miriam Tucker. All rights reserved.