Probiotics? The pros and cons

You’ve almost definitely heard about probiotics and how they’re amazing for your gut microbiota (which’ll help your overall health) and how you can get them in yoghurt and other foods or as tablets. Improving your health just by eating yoghurt instead of milk with your cereal sounds great, but the question is, do they actually help?

Firstly, your gut microbiota (that’s all the bacteria living inside your intestines) has been something we’ve been hearing a lot about recently with many scientists studying its role in health. While there’s much we don’t understand, your gut bacteria have been shown to have significant impacts on your overall health, so those news headlines aren’t exaggerating too much. Along with it, you hear that antibiotics damage your gut bacteria and that probiotics can help rebuild that gut and are better for an overall healthy lifestyle. Consequently, some doctors and pharmacists will prescribe probiotics alongside antibiotics to lessen the impact on your body’s natural bacteria (note that probiotics aren’t things that’ll help all bacteria flourish, so they aren’t counteracting the important work of the antibiotics in killing the infectious bacteria).

Probiotics are live bacteria of specific species and strains that are are beneficial to you and your digestive system. The most common ones are lactobacillus and bifidobacteria that help with digestion of certain compounds in foods. The types of gut bacteria and their proportions are also closely linked to obesity, as shown in this series of posts from the Biochemist blog.

Probiotics can now be found in many supermarket and pharmaceutical products and are estimated to be the most profitable area of the current pharmaceutical industry. However, they’ve come under widespread criticism for many reasons:

  • Many yoghurts and milk-based products that advertise probiotics have a very high sugar content that may outweigh the benefit of the probiotics.
  • The stomach acid (pH 1-1.5) kills many of the probiotic bacteria strains.
  • The amount of bacteria of a probiotic strain in a serving is several orders of magnitude below the amount in your intestines so makes very little impact (compare that to dropping 1mL of water into a 1 L jug or even a 10 L jug).
  • These strains may not be as highly adapted to the intestinal environment as the bacteria currently present.

Probiotic tablets are slightly better as they avoid the sugar issues and may have better bacterial strains, but their effectiveness is still questionable (and they’re expensive too).

Overall, this means that they don’t currently seem to be a good option. So how can you improve the health of your resident bacteria?

Prebiotics seem to be a far more promising path. They are compounds in food (or in a tablet) that help to promote the growth of healthy bacteria. Main foods that include them are fruit, vegetables, whole grains … all foods that are high in fibre. In fact, these foods are more effective overall in promoting gut health than the expensive pill-based versions due to the combination of compounds within these foods.

So prebiotics seem to be far more effective than probiotics, so don’t get caught out with clever marketing that encourages you to buy probiotic foods without doing your research first!





3 thoughts on “Probiotics? The pros and cons

  1. I’d be interested to see references for studies regarding the effectiveness of probiotics vs prebiotics if you have them.


    1. This study here ( looks at how probiotics affect general gut microbiota and this one ( looked at the effects after having taken antibiotics.

      This open-text literature review ( concluded that probiotics are seen to have some effect, but that diet and prebiotics are also an important part of maintaining healthy microbiota.

      Hope these are interesting and helpful!


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