This piece was written by one of our contributors; nutrition-trained chartered psychologist Kimberley Wilson.
Depression is the leading cause of disability worldwide. This means that more people suffer a reduced quality of life due to the depression than any other illness. Furthermore, despite effective anti-depressant medication being available since the 1950, rates of depression continue to rise as do levels of ‘treatment resistant’ depression – depression that doesn’t respond to medication. The growing levels of depression and poor treatment response rate have led to a much-needed and long-overdue rethink of the causes of depression and the factors that affect brain health more generally. One of these factors is nutrition.
For decades studies have shown a relationship between a consistently healthy diet and reduced risk of depression in the general population and in women. Until recently this research had been correlational; it showed a relationship but could not say what caused what. It could be, for example, that depressed people are more likely to eat a poor diet. All of that changed in 2017 with the publication of the SMILES Trial, a randomised controlled trial that effectively used dietary improvement as a treatment for depression. In this study 30% of the participants, who all had an established diagnosis of depression at the start of the trial, went into remission i.e. they were no longer considered depressed. Since then other research teams around the world have replicated the finding. Improving nutrition appears to play an important role in improving brain health and mental health outcomes. Why might this be?
Well, the simple answer is that your brain is an organ. And in the same way that your heart relies on healthy diet to provide the nutrients it needs to work properly, your brain needs to be properly nourished to function well. But your brain isn’t just any organ. It is the most important organ in your body and the hungriest. Despite being only around 2% of your total body weight, your brain makes up 20%-25% of your daily energy requirement. So your brain punches well about its weight in terms of energy and nutrient need. And when it doesn’t get those nutrients it starts to suffer.
Poor nutrition has been linked to increased risk of a range of mental health conditions including depression; stress and PTSD; psychosis and schizophrenia; and dementia. In addition, certain nutrients have been shown to improve cognitive function in areas such as focus, attention, processing speed, decision-making, and memory. So, it is clear that good nutrition is good for the brain yet few people know what to eat to help protect brain health and function.
Some key foods for brain health…
Oily fish and seafood 🐟
- herring (including kippers and bloaters)
Oily fish contains particular types of unsaturated fats called ‘essential fatty acids’. They are called ‘essential’ because the body is unable to synthesise them. You must get these fats from the diet. But why are they so important
Two kinds of essential fats – eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) – play particularly important roles in the brain because they form the cell membranes. They act like the exterior walls of a house, keeping what should be on the inside in, what should be on the outside out and only letting in desirable guests. If you are not getting enough of these fats in your diet it is as if, bit by bit, the bricks are being taken out of the walls. The house will be able to stay upright for a while but eventually it will start to break down.
DHA also helps to supports cell signalling, allowing brain cells to communicate with each other, while EPA reduces inflammation.
Berries have both immediate and long-term effects on the brain because the help to keep the tiny blood vessels that feed the brain flexible and healthy. In one trial 200g of fresh blueberries resulted in improved word recall in children, and improved their accuracy on tests. In adults, blackcurrants improved attention during a long, tiring task and cherries are linked with better mental flexibility, the ability to switch from one task to another. Another trial found that pomegranate anthocyanins (the compounds that makes them red) protected against memory deficits.
- wholegrains such as wholewheat bread
- pot barley
- whole oats
- brown rice.
- Legumes such as black beans, broad beans , chickpeas and lentils.
- Cooked and cooled carbs such as potato salad and pasta salad from the deli counter.
Cooked and cooled carbs such as potato salad and pasta salad from the deli counter. For lots of reasons, that I don’t have space to go into here, a healthy gut is crucial for a healthy brain. A broad range of fibres is essential for feeding the trillions of microorganisms that make up the gut microbiota. In turn the produce various compounds including vitamins, hormones and short-chain fatty acids that support brain health.
B vitamins are so important for brain health that a deficiency in them can cause nerve damage and even mimic the symptoms of dementia. B vitamins are found predominantly in animal foods such as meat, milk and offal so it is crucial that people vegans of people who rarely eat these foods take a good quality B complex supplement to ensure they are not missing out on these important brain health nutrients.