Probiotics Aren't Great For Everyone, According To New Research

    There's a lot of research that you may not know about.

    Probiotics are thought to keep your gut bacteria balanced and healthy, but new studies of these over-the-counter supplements indicate they may not be as effective in boosting gut health as some people think.

    Probiotics are pills of living bacteria or yeast that are thought to balance your gut bacteria (microbiome) when there is a depletion of "good" bacteria, such as after a course of antibiotics.

    "Good bacteria" are the species that live in the human gut, breaking down foods and regulating immune function.

    The human microbiome has been dubbed the "forgotten organ" because of its ability to modulate hormonal and immune responses in the body. Depression, anxiety, chronic fatigue syndrome, alcoholism and restless leg syndrome have all been linked to imbalances in the microbiome.

    Two studies published in September suggest that it may be misguided for many consumers to consume generic probiotic pills in order to maintain "good" bacteria levels in the microbiome.

    The studies, from the Weizmann Institute of Science in Israel, found that the effects of the same probiotics vary from person to person, and that some people's microbiomes can even resist the introduction of new bacteria entirely.

    Probiotic supplements also appear to have different effects at various points along the intestinal tract for different people.

    The first study observed the effects when 14 people were given a standard cocktail of bacterium in a probiotic pill twice a day for four weeks.

    Both of the studies conclude that swallowing generic probiotic pills containing live strains of bacteria such as Lactobacillus or Bifidobacterium may not be universally beneficial.

    The concept of probiotics was first proposed by Elie Metchnikoff, a Russian zoologist, in 1910, who observed that Belgians were living longer due to their high intake of fermented milk products.

    Probiotics have a number of proven benefits and are often recommended for bacterial gut infections that cause diarrhea.

    Probiotics have also been shown to balance the microbiome after taking antibiotics that indiscriminately kill "good" and "bad" bacteria in the gut. They have also been shown to reduce blood pressure, improve blood cholesterol levels and assist in diabetes control.

    These results have led to a strong interest in probiotics and consumers who are otherwise healthy have begun taking the bacterium capsules.

    There has been limited research conducted about the potential harms of probiotics, and one of the Weizmann studies indicates that probiotics might actually hinder the regrowth of "good" bacteria in the gut after taking antibiotics.

    Dr Nural Cokcetin, a researcher in prebiotics and probiotics from the University of Technology, Sydney, told BuzzFeed News that the composition of a microbiome can vary markedly from country to country, depending on the diet consumed.

    Researchers are unsure of why the microbiome varies, but Cokcetin said genetics, environmental factors, exercise, and diet all seem to play a role, and that because of this variance, it follows that the benefits of probiotics vary as well.

    Cokcetin said consumers should continue to take probiotics if it makes them feel better as they're "probably not going to do any harm".

    Dr Hannah Wardill, a microbiologist from the University of Adelaide, told BuzzFeed News that the lack of regulation and understanding around probiotics made consuming them a matter of individual experimentation.

    Cokcetin and Wardill believe the probiotic market is moving towards a more personalised approach. Private companies to test individual microbiomes – at a cost to the consumer of about $300 each – are being established, including uBiome in the US and Microba in Australia.

    Wardill believes the probiotics market will move away from generic capsules and begin to tailor to a person's individual gut bacteria colonies.

    Cokcetin says prebiotics may be another key to balancing the individual microbiome. Prebiotics are the foods that humans can not digest, meaning that they reach the lower gut and can be used as a food source by our "good" gut bacteria.

    While foods we recognise as probiotic such as yoghurt and kombucha may not necessarily help to balance everybody's microbiome, Cokcetin believes these products can have a prebiotic effect that allows "beneficial bacteria to start kicking in".

    She says the increasing interest in probiotics could be a good thing for our personal understanding of human health.

    "I think the message is to have this diverse microbiome – and we can do that by eating lots of good foods, especially prebiotic foods," she said.