Are you a victim of a marketing scam which has duped almost 60 percent of UK households? Have you succumbed to those probiotics adverts, where a woman endorses her daily fix of bacterial yoghurt as a cure for everything? And if so, have you paused to consider the science behind it?
Probiotics are a ‘functional food’, supposedly providing health benefits alongside nutrients. The carefully scientific-sounding name describes yoghurts or beverages that contain billions of bacteria. These friendly bacteria are of the Lactobacillus strain, which, according to Activia’s bright packaging, ”help regulate your digestive system”. (1)
But hang on; these friendly bacteria reach the intestines via the oesophagus and stomach. Stomach acid does a pretty nifty job of killing microbes that enter it in order to prevent disease. And those nice ones in your yoghurt aren’t marked with a ‘handle with care’ tag.
Haven’t the manufacturers ensured their probiotic bacteria survive? Unfortunately not according to various independent studies, most notably a commission by the Food Safety Authority (FSA) which found that many bacteria couldn’t survive stomach conditions. Even the most resistant were wiped out by the upper intestine. (2)
But what would happen if they somehow were to reach your gut? Not a lot, unfortunately. The same FSA analysis found that “addition of probiotic did not affect significantly the total number of bacteria growing… Little difference was also seen on the levels of main bacterial species.” Another report by the European Food Safety Authority last year found that of 12 Yakult studies which claimed health benefits for probiotics (such as increased immune defence against colds), precisely none had produced satisfactory evidence. (3)
So bacteria in probiotics: often don’t make it through your stomach, and even if they do, tend to be eliminated by your upper intestines; don’t alter bacterial levels in your gut; and don’t improve your health, at least not in the ways manufacturers claim.
Buying probiotics won’t kill you, but it won’t do you much good either. As the student loan dwindles depressingly quickly, it’s surely worth considering switching your Yakult for good old Sainsbury’s Basics yoghurt. It doesn’t claim to magically restore your intestinal health. But nor will it hurt your wallet.
Not-Sci is produced by BlueSci, the Cambridge University science magazine. Communicating good science accurately is hard to do. In this column, we aim to weed out the good from the bad and tackle some of the pseudoscientific scandals that plague modern society.
This week’s article was written by Beth Jones.
(1) http://www.activia.us.com/how-activia-helps/what-is-activia.aspx
(2) http://www.food.gov.uk/multimedia/pdfs/probioticreport.pdf
(3) http://www.guardian.co.uk/society/2010/oct/19/efsa-rules-probiotic-health-claims-unproven
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