For the last decade, food companies have been priding themselves on adding probiotics to everyday nutritional staples like yogurt, cereal and even dark chocolate. And the public has been gobbling them up.
On paper, probiotics are a tough sell, especially when described as live microbes that are meant to be ingested by the billions. But their positive effects have been widely and actively reported, thus allowing them to infiltrate the mainstream market easily and quickly.
In a 2012 Ipsos-Reid survey, 98 per cent of respondents said they had purchased some kind of functional food or beverage product over the past year, including probiotic-fortified yogurt. And the North American probiotic market is expected to increase to more than $6.5 billion US by 2023.
Probiotics claim to sustain healthy gut bacteria, and aid in digestive issues as wide-ranging as minor cramping and bloating to colitis and irritable bowel syndrome by preventing bad bacteria from growing and adhering to the lining of the digestive tract. This in turn enhances the immune system and helps to maintain general health. Suffice to say, they have been positioned as a valuable addition to a healthy lifestyle.
“I recommend probiotics to most of my clients for digestive health, especially if they have been on antibiotics recently or if they have digestive issues such as IBS, Crohn’s or colitis,” says Christy Brissette, dietitian and president of 80 Twenty Nutrition, a food consultancy and communications company.
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But a study published in May in the journal Genome Medicine is painting a less flattering picture of probiotics. Oluf Pederson, a professor of medicine at the University of Copenhagen and director of the Novo Nordisk Foundation Centre for Basic Metabolic Research, conducted the study that calls into question what effects, if any, probiotics can have on an otherwise healthy digestive tract. In examining hundreds of reports on the subject, and narrowing them down to seven that fit certain criteria, he and his colleagues discovered that while some strains of probiotics have been shown to help in the management of irritable bowel syndrome, ulcerative colitis and traveller’s diarrhea, only one showed any shift in the gut bacteria of healthy adults.
“This came as a surprise to us that there is no scientific evidence that probiotics do have an impact on the gut microbiology,” Pedersen said to the Washington Post. “The problem is many people think there is a benefit.”
It’s not just consumers, either. Physicians have long been prescribing probiotics to patients not only for controlling their gut bacteria, but also for addressing health issues as disparate as upper respiratory tract infections and atopic eczema. But they are quick to point out that there’s no one magic probiotic (they come in hundreds of different strains that address different issues) and they don’t work on everyone equally.
“Each person’s microbiome contains over 100,000 billion bacteria, hence there will be some variability from person to person,” says Dr. Sapna Makhija, gastroenterologist and co-founder of the GI Health Centre.
While Makhija is reluctant to stop recommending a daily probiotic to her patients, she does recognize that further studies need to be done to determine exactly how much benefit they can bestow on the healthy gut. And she also advises patients to consider the source.
“The majority of patients we see have seen a naturopath before us and were put on various forms of probiotics,” she says. “Naturopaths tend to sell their own promoted products and some of these probiotics don’t undergo the same scrutiny as other medications would.”
She suggests consulting a medical professional first and making sure there’s a high enough concentration of the probiotic in the supplement. The recommended dose varies from person to person, and can range anywhere from one to 10 billion CFUs (colony-forming units) over three or four doses.
It’s doubtful that Pederson’s study will do much to curb probiotic consumption, though doctors are eager to correct the promises espoused by the natural health community. Especially since probiotic supplements aren’t heavily regulated by Health Canada – as of 2009, only 16 species had been approved for inclusion on food labels.
On the plus side, there are few side-effects associated with probiotics, aside from some initial bloating or gas. (Brissette advises cancer patients to steer clear of them since their immune systems are compromised.) So it’s unlikely that even those who don’t stand to benefit from them will avoid them.
“Any therapy can have a placebo effect,” Makhija says. “Patients report a subjective improvement, so it’s hard to measure. But if it makes them feel better, even psychologically, it’s having a beneficial effect.”