According the latest government statistics obesity is on the rise, there is also a link to Covid deaths with nearly 8% of critically ill patients in intensive care being obese, compared with 2.9% of the general population. The WHO has stated that being overweight and obese is the fifth leading risk for global deaths with at least 2.8 million adults dying each year.
Eating too much is clearly not good for your health but how about what you eat, how might that impact your health, in particular your brain?
Viva las Vagus
Have you ever used your gut instinct, had butterflies in your stomach or when feeling nervous had to rush to the toilet? If so then you already have some evidence of the connection and importance of your gut to the way you think and feel. The vagus nerve is the longest cranial nerve and runs from the brain stem to part of the colon in effect making the connection. The biggest influence on the levels of activity of the vagus nerve are the trillions of microbes that reside in the gut. The vagus nerve is able to sense the microbe activity and effectively transfer this gut information to the nervous system and ultimately the brain. Watch this 2-minute video that shows how this works.
Scientists refer to the relationship between the gut and the brain as the “gut brain axis”. The brain sends chemical signals to the gut through the bloodstream, one such example is the feeling of being full or hungry. But and this is the interesting part – the stomach talks back; gut bacteria send messages in the same way the brain communicates using neurotransmission. Prior blog – The learning brain.
Exactly what the messages say depends on what you eat, a gut filled with fruit and vegetables will have different microbes to one that has just consumed a Big Mac. This is a very new area and most of the research has been completed on rats but there is already some evidence to suggest that junk food impairs memory.
Hopefully this gives you some idea as to the strong connection that exist between your stomach and your brain. We can now move on and consider what specific types of foods can help when learning.
These Ted talks are well worth watching if you want to find out more – Your Gut Microbiome: The most important organ you’ve never heard of (11m), and Mind-altering microbes: How the microbiome affects brain and behaviour (6m).
What to eat when studying
The first thing to say is that I am far from an expert on nutrition and so the focus here is more on the impact food has on mood, concentration, cognition and memory. Secondly, to give this some context it might be worth thinking about what you eat in the same way an athlete does. They pay close attention to their diet to make sure their body is in the best possible condition in order to compete because if not they are reducing their chances of success. However, a good diet is no substitute for the hard work they have to put in at the gym, you have to do both. Short video on how nutrition is key to sports performance.
- Apples, berries and Citrus – The British Journal of Nutrition published research in 2010 (The impact of fruit flavonoids on memory and cognition) indicating that consuming certain fruits such as berries, apple and citrus, that are rich in flavonoids can help improve memory and cognition.
- Dark chocolate – Research published in the Frontiers in Nutrition (Enhancing Human Cognition with Cocoa Flavonoids) found that dark chocolate which also contains flavonoids improved memory in both the short and long term. But remember many types of chocolate are high in sugar, fats, and calories so it’s not all good news.
- Rosemary – Northumbria University’s Department of Psychology found that herbs such as rosemary and lavender impacted memory, with the scent of rosemary enhancing memory but lavender impairing it. Maybe Shakespeare knew what he was talking about when he said ‘rosemary is for remembrance’.
- Oily fish and walnuts (omega 3) – There is a much-published connection between omega three and the improvement in learning and memory. However, many of these claims are exaggerated to promote a particular type of food or brand with most having such small doses to make little or no difference. There is some evidence published in the medical journal of the American Academy of Neurology that found people who ate more seafood, which naturally contains omega 3, had reduced rates of decline in semantic memory. But there is little evidence to show that supplements work at all. The best advice is to eat fish and nuts as part of a balanced diet but don’t expect your exam results to improve by that much.
- Fruit and vegetables – A study conducted by Pennsylvania State University in April 2012 found an association between consuming fruit and vegetables and being in a positive mood.
- Water – Despite being the least exciting of them all, water remains one of the best ways in which you can improve brain functionality. Research published in the American Journal of Clinical Nutrition studied 101 participants to see if low water consumption impacted cognition. The result was those who had reduced amounts of water experienced poor memory, reduced energy levels and feelings of anxiety, but those drinking water experienced the opposite.
The evidence on specific foods and its impact on cognition and learning is complex and nuanced. However the connection between the stomach and the brain although still in its early stages has greater potential to lead us to a better understanding as to what we should eat to improve our mental wellbeing.
In the meantime, the best advice is to think about how your diet impacts you personally, identify when you feel best studying is it before a meal or after, pay attention to snacking and of course drink lots of water, eat your greens, all as part of a balanced diet.