I have seen various varieties of pro-biotic yoghurt drinks on the shelves in supermarkets. For those unfamiliar - they are claimed to contain bacteria that is beneficial to the human body and specifically the digestive system.
There is evidence to suggest that the contents of the gut/intestine are relevant to the digestion and processing of nutrition. Such as: http://ofid.oxfordjournals.org/content/2/1/ofv004.full
However what sets my skeptic running is when I see claims: http://activia.us.com/probiotics-benefits/digestive-health
may help reduce the frequency of minor digestive issues like bloating, gas, discomfort and rumbling, when consumed twice per day for four weeks as part of a balanced diet and healthy lifestyle.
(Emphasis mine). There are many things that may help you, as part of a healthy and balanced diet.
Miguel Freitas, PhD, medical marketing manager for Dannon Co., says the benefits associated with probiotics are specific to certain strains of these "good" bacteria. Many provide their benefits by adjusting the microflora (the natural balance of organisms) in the intestines, or by acting directly on body functions, such as digestion or immune function.
But is there any research to substantiate the general claim that 'probiotic yoghurt drinks improve health' and for bonus points - any research indication which ones actually make a difference, given different bacteria in each?