Most of us believe we are what we eat. But have you ever thought you could ‘feel’ what you eat? As Fiona Godlee, editor of the BMJ, says, mood can improve as the result of eating foods that reduce inflammation and support the gut microbiome, the trillions of bacteria and viruses in the gut.
Improving what and how we eat helps not only protect our physical health but our mental health too, proposes Joseph Firth and colleagues in the same edition of the BMJ.
Indeed, they point out that the Mediterranean diet, rich in fruit, veg and legumes with only occasional red meat, is linked to a lower risk of depression. On the other hand poor mental health tends to result from our unhealthier eating patterns.
Eating highly refined carbohydrates with a high glycaemic index can raise the risk of obesity and diabetes.
Glycaemic index is a way to rank carbohydrate in foods according to how quickly it’s digested, absorbed by the body, enters the blood and raises insulin levels.
Diets with a high glycaemic index containing large amounts of refined carbohydrates and sugar may undermine your psychological wellbeing.
Progressively more refined carbs in your diet can lead to more depressive symptoms. Even diets with a high glycaemic load given to healthy volunteers can markedly increase depressive symptoms. These days when we discuss food and mood we can’t ignore the gut microbiome because it interacts with the brain in both directions, via nerves, inflammation and hormones.
Altered interactions between the brain and gut microbiome affecting mental health have been studied in animals and are illuminating.
Emotional behaviour changes are seen in animals with changes in the gut microbiome. This is paralleled with major depression in people with alterations of the gut microbiome.
Moreover, transfer into animals of faecal gut microbiota from patients with depression appears to induce depression-like states in those animals.
Conversely, consuming the Mediterranean diet, high in fibre, polyphenols and unsaturated fatty acids, can promote gut microbial activity which results in anti-inflammatory substances.
Furthermore, a recent study found that the ingestion of probiotics by healthy people, which target the gut microbiome, can alter the brain’s response to become more attentive and may ease symptoms of depression.
Oh well, you might say, these studies don’t amount to much on their own.
But when viewed together, they suggest the gut microbiome could modulate emotions in the human brain. Now that’s a startling assertion, though no cause and effect has been proven so far.