It is well known that what you eat can have an impact on your overall physical health. But in recent years, scientists have discovered that our diet can also play a key role in our mental and brain health.
Latest research – the SMILES trial
The SMILES trial – the first RCT (randomised controlled trial) investigating dietary pattern and depressive symptoms found subjects following a diet based on the Mediterranean diet, one of the most researched dietary patterns and known for its positive impact on our physical health, had significant improvements in their depressive symptoms compared to subjects receiving social support alone. As a reminder, the Mediterranean diet involves high intakes of vegetables, fruits, wholegrains, healthy fats, oily fish and lower intakes of highly processed and sugary foods and less meat.
The results which have been published in an international journal, found those following the Mediterranean diet had a much greater reduction in their depressive symptoms over the three-month period, compared to those in the social support group. It is also important to highlight that the trial was conducted over a three-month period and that the benefits or improvement in depressive symptoms were noticed after this time period.
Link with inflammation
Evidence also demonstrates many mental and brain states are linked to our immune systems and inflammation, which is a chronic activation of our body’s immune system. You may already be familiar with the terms ‘gut health’ and ‘gut microbiome’ both of which have been linked to mental health with several overlapping mechanisms involving the gut microbiome, the central and enteral nervous systems and our immune systems. Research has also shown that chronic low-grade inflammation may lead to an increased risk of depression and that inflammation may be a possible link to cognitive decline.
But what causes inflammation?
Inflammation can be caused by several factors – psychological stress, which is usually resolved by our bodies, could in periods of prolonged stress lead to a chronic inflammatory state. Periods of sleep deprivation have also been associated with impaired functioning and inflammation. Along with other modifiable factors, poor diet can significantly contribute to the state of inflammation. Evidence from large population-based studies shows that consumption of Western dietary patterns (those that are high in processed foods, saturated fats, sugars and salts) is linked to a greater concentration of blood inflammatory markers such as the C-reactive protein, which is produced by the liver in response to inflammation, infection or injury. Based on this, we should be looking at ways to reduce inflammation within our bodies, particularly during stressful periods of our life. At the moment as we're in lockdown 2.0, this could be easier said than done.
How can we reduce inflammation?
Dietary patterns such as the Mediterranean diet that I talked about earlier, have been associated with a decrease in pro-inflammatory response and may support cognitive function. Intervention studies have also shown that inflammatory states improve when diet is improved and fruit and vegetable intake is increased. But why is this? If we are following a diet with high levels of plant-based foods we will be consuming a diverse range of fibre. The gut microbiome loves this diversity and produces a range of metabolites from breaking down the fibre and these are thought to play a significant role in regulating inflammation.
So what should you do differently?
Overall, the take home message is that we should ideally be consuming 'nutrient dense', minimally processed diets to protect our physical and mental health. Try and up your intake of plant-based items per week, aim for diversity (around 30 different types) and explore new options when out shopping/ordering online. Also remember to carve time out of your day for your own self-care, try to manage stress levels and prioritise sleep. As I said before, easier said than done at the moment but give it your best shot.
Photo credit: Tayla Jeffs @unsplash