Do you get your daily dose of bacteria? If the answer is ‘yes’, the chances are that is because you have yoghurt for breakfast. It may be a fancy ‘probiotic’ brand, with some supposedly extra-beneficial bacteria added, or just bring you regular yoghurt-making cultures.
Either way, you and millions of others are picking up on outdated advice. Pioneer microbiologist Elie Metchnikoff singled out milk-fermenters (lactobacilli) as ‘good’ bacteria over 100 years ago, without much evidence. His recommendation to eat them has survived on one side of our contradictory attitudes to microbes. On the other, we fear germs, and attack them with antibiotics and disinfectants.
Both views are about to shift, as new science sheds light on the intimate connections we all have with a vast, complex community of microbes. Your colon, for example, which Metchnikoff regarded as a ‘vestigial cesspool’, is home to a teeming ecosystem, which contributes to digestion, to production of vitamins, and to fine-tuning of the immune system.
As researchers discover more about the microbes that live in us – in our guts, mouths, genitals, and elsewhere – new ways of managing this vital community come to the fore. And they will lead to new, more scientifically sound products. Drugs that zap pathogens will still be life-savers, in their place, but we will probably be less prone to wage total war on our microbes for lesser ailments. Broad-spectrum antibiotics are like napalming a rain forest because all that foliage shelters predators. We will move to more subtle approaches, cultivating our own preferred mix of microbes. With one firm of analysts forecasting a human microbiome (the term for the total complement of microbes) market worth $650 million dollars worldwide in 2023, what might be in store?
One medical application under development is microbial profiling for diagnosis and personalised treatment. DNA-based analyses of gut microbes are becoming fast and cheap. The species composition they reveal may help assess risks of a range of conditions, including inflammatory bowel disease and cancers, and judge which drugs might work best. French start-up Enterome Bioscience is developing diagnostic profiling for patients with Crohn’s disease and metabolic disorders. Metabiomics Corporation in the US promises a similar approach to spotting incipient colon cancer.
There will be medical products based on beneficial microbes, too. At the moment the best-validated microbial treatment is a total faecal microbial transplant – yes, that means what it says – as a simple remedy for patients who have a colon riddled with harmful strains of the bacterium Clostridium difficile. It works, but is a blunt instrument: just transfer the whole damn ecosystem! There will be better ways of repopulating the colon of someone whose normal microbiome has been depleted, using less complex mixes of bacteria.
Expect to see more products that supply helpful bacteria for other parts of the body, too. Anti-dandruff treatments (more a fungal than a bacterial problem, but the principle is the same) are under development. Chewing gum that helps prevent tooth decay is a serious possibility. There are already genetically engineered bacteria that colonise the surface of teeth and help prevent them becoming a home to Streptococcus mutans, which transforms sugar in the mouth into acid that corrodes tooth enamel, but turning them into a product has not yet overcome regulatory hurdles.
An alternative route, a mouthwash that contains a specific antimicrobial peptide that targets S. mutans, might be a better bet. Meanwhile, US shoppers can already buy oral probiotics for humans and, if they wish, their pets. Health claims are largely ruled out by the regulations on marketing probiotics as food products, so the pitch here is mainly cosmetic, even for pets. Sprinkle a patented blend of three microorganisms in powder form on your dog or cat food once a day, and the beast will have fresher breath and whiter teeth.
The next step is products that supply the right bacteria to anoint yourself with. A spray-on for skin care, intended as a substitute for soap and deodorant, is already under development and has been tried by a few intrepid journalists. The company bringing it to market, AOBiome, says that its patented ammonia-oxidising bacteria, “have been shown in a cosmetic clinical trial to improve the appearance and feel of people’s skin.” It quotes a price of $99 for a month’s supply, but has yet to scale-up production so has a near threemonth waiting time for orders in the US.
Further ahead, we have to speculate. But imagine a future in which we spray our homes with bacteria instead of disinfectant, bring home-fermented foods into hospital to strengthen a loved-one’s recovery, or dab a cunning mix of bacteria behind each ear to boost our pheromones before a date.
Entrepreneurs are speculating freely, too. Gilad Gome, founder of a California start-up called Personal Probiotics, begins prosaically but then gets more fanciful in an interviewvon the website Motherboard. He suggests that a woman could protect herself from urinary tract infections and pathogens by taking a probiotic, and that the bacterial strains used might also be modified so that “if she wants she can hack into her microbiome and make her vagina smell like roses and taste like diet cola”. Whether or not this is a serious proposition, it is an effective way to get attention for a new company.
Meanwhile, there will be a large number of, er, less ambitious probiotic formulations that, unlike most of the old-school probiotics on the shelves, will be tested well-enough to allow their makers to make specific health claims. This June, Cultured Care probiotic gum, on the market as a mouth-freshener for some years, was approved by Health Canada. The makers, Prairie Naturals of Vancouver, can now advertise that the benefits of the bacteria the gum is loaded with – Streptococcus salivarius – include fighting bad breath and improving oral health. It is likely to be the first of many such products. - Jon Turney
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