Friendly yes, necessary no

THE Food Standards Agency is to investigate those "healthy bacteria" probiotic drinks and yoghurts that fill the supermarket shelves, amid concerns that their health benefits are being exaggerated.

We all carry about 2kg of "friendly bacteria" in our bowels, where they are thought to aid digestion, neutralise toxins and boost immunity, so it makes sense to look after them.

But ready-made probiotic drinks may not be the best way to do it.

These drinks contain tens of billions of "friendly bacteria" but that is a drop in the ocean compared to the number already in the bowel. Or, to put it another way, expecting a

probiotic drink to significantly alter the bacterial make-up of your bowel is like expecting to be able to notice 10 extra people on Oxford Street on a busy Saturday afternoon.

So, if probiotic drinks are not necessarily the best solution, what is?

Most experts believe we should concentrate more on looking after the healthy bacteria already living inside us, rather than worrying about introducing new ones.

And the simplest way to do this? Just feed them with a diet rich in the fibre found in cereals, fruit and vegetables.

Most fruit and vegetables come naturally impregnated with their own probiotics, including lactobacilli plantarum, the bacterium used in some of the bestselling probiotic drinks.