Should I use probiotics to improve my mood?

Pre- and probiotics are undergoing a huge boom in research and discovery at the moment, and recent developments have suggested that probiotics may be used to treat depression and anxiety, and improve sense of wellbeing.

Feed your microbiome while you feed yourself

The gut microbiome, or the community of bacteria that live in our digestive system, are not just passive parasites living off our hard work. In fact, it is practically the opposite – without our bacteria, we would barely be able to survive, and the fact is that our personalities are vastly affected by what thrives in our intestines. The bacteria inside our gut create all sorts of useful substances including neurotransmitters and hormones like serotonin and GABA that modulate brain development and activity, affecting our mood. GABA, in particular, regulates the firing of neurons in the brain, leading to a calming and relaxing effect.

Mice who were brought up in entirely sterile environments, and therefore have no detectable gut bacteria, have shown this in several studies. These germ-free mice (GF mice) have a massively exaggerated stress response that can be reversed once probiotics are administered. GF mice have abnormal brain development that causes anxiety and inability to cope, including a tendency to just “give up and die” in life-threatening situations, whereas mice on probiotics have been shown to act the same as mice on antidepressants.

The hippocampus and amygdala regions of the brain are associated with fear, anxiety and response to stressful situations. The microbiome appears to regulate the creation of neurons in these regions, as GF mice have an increased volume in both areas, causing the increased stress response compared with their normal peers. This is thought to be due to “the gut-brain axis” whereby what goes on in our gut directly affects our brain.

Mice are incredibly sociable creatures, who not only need to regularly interact with familiar mice but will also actively choose to spend time with mice they’ve never met before and bond with them. Not so with mice who are brought up germ-free. The sterility of their gut appears to make them antisocial and anxious when interacting with new mice, and less willing to interact with familiar ones. There is an ever-increasing body of research that shows how our gut bacteria affect our sociability.

One high-quality study on healthy human women showed that drinking fermented milk with 4 different types of bacteria increased mood and ability to cope with sadness, changing the women’s behaviour when faced with stress.

The microbiota of the gut produce substances that get used in the formation and maintenance of the blood-brain barrier – where ageing, stress and sedentary lifestyle can decrease it, exercise, meditation and gut bacteria can “tighten” it back up and protect the brain from roaming nasties. The use of “psychobiotics” is being investigated for the treatment of severe psychiatric disorders such as schizophrenia.

So should I take probiotics?

In short, yes, you probably could take probiotics to help improve your mood, especially if you suffer from mild depression or anxiety. Probiotics at this stage are no substitute for medication for those with more severe forms of these conditions, but it may well be worth adding them alongside medication, following advice from your doctor.

Which ones should I take?

  • From the research done so far, it would seem that those bacteria which cause an increase in production of GABA would be most helpful for improving mood, such as those of the Lactobacilis and Bifidobacterium families. A good start could be a fermented milk drink that contains these.

Why don’t I just take a GABA supplement?

  • GABA is extremely unlikely to cross the blood brain barrier when ingested orally – your body has all sorts of mechanisms to protect itself from the things you swallow, and has a fairly strict shortlist of what it will absorb from its digestive process, so the best way to get more of the stuff is to take bacteria that can create it and deliver it on the gut-brain axis.

Don’t forget to keep the bacteria alive once you’ve swallowed them!

  • Eating lots of fresh fruit and veg, and other foods high in fibre that our gut bacteria love to munch on, like potatoes, nuts and seeds, all help to maintain the population in your gut.

See the next chapter in our Gut Series to find out which foods may be of most help for feeding your gut bacteria and maintaining happiness.

If you’re interested in learning an awful lot more on the gut-brain axis, probiotics and their potential use in various treatments, I can highly recommend the free video lecture series by Dr John Cryan over at the NCCIH.