Probiotic drinks, brain-boosting superfoods, gut-healthy snack bars: every day we’re bombarded with information about what and what not to eat. Some foods move abruptly between these categories depending on who you ask: if a gut-healthy snack bar is ultra-processed, does that cancel out its benefits? You’d be forgiven for thinking that every food choice you make has immediate, direct consequences for your health. And, increasingly, your brain. Does broccoli make you brighter? Can a pickle really act as a pick-me-up?
There is some scientific truth to this magic. By now you may have heard that people with poorer mental health, such as those experiencing depression or anxiety, have a different balance of bacteria in their gut – a reduction in the richness and diversity of their microbiomes. This fits neatly with elegant (albeit slightly gross) experiments in the lab in which transplanting faeces from people with depression into rats induces “depression-like” behaviours. How is this possible? It’s because your gut sends signals to your brain via the vagus nerve, your immune system, and other means, passing on information about how things are going down there. And so, the theory goes, a less-diverse microbiome might be the cause of a depressed or anxious brain. Maybe a gut-healthy snack bar really would help?
