New research indicates that many probiotics are ineffective and some may even cause harm. Now scientists say we should switch to prebiotics.
Over the past two decades, it seemed that our guts had never had it so good. Probiotic products claiming to rid the body of the bad bacteria that causes illness burst on to the market and two million of us now swallow their promise of improved digestive health, provided by so-called “friendly bacteria”. We spend almost £350 million a year on drinks, yoghurts, powders and capsules, in the hope of improving our gut health. But is it money well spent? A growing number of experts think not. While they do not dispute that a balance of gut flora is beneficial, many believe that probiotics are not as helpful as was once thought.
Studies supporting the use of probiotics for general wellbeing, and as an additional support for people with specific illnesses, have been plentiful in recent years. This month, for instance, Swedish researchers revealed that a course of probiotics can offer protection for those with pneumonia. But critics are now doubting their usefulness. “In some areas, there is evidence that taking a probiotic supplement can be helpful,” says Anna Denny, a nutrition scientist at the British Nutrition Foundation. “But it is not clear-cut and not all probiotics are helpful to all people.”
The Russian Nobel prize winner, Élie Metchnikoff, is credited with having discovered probiotics at the beginning of the 20th century when he discovered that Bulgarian peasants who consumed milk containing fermenting bacteria appeared to enjoy extraordinarily good health.
It is now accepted among nutrition scientists that so-called friendly bacteria account for 10-15 per cent of bacteria in a healthy adult gut and that levels become depleted through a poor, low-fibre diet, or other factors such as stress, courses of antibiotics or illness. Proponents claim that probiotic supplements, which provide a regular shot of live, beneficial bacteria, help to top-up a body's natural supplies. But even those who were once self-confessed fanatics are questioning their place and proposing alternatives.