A glass of orange juice for… depression. And this is thanks to the juice's valuable antioxidants that support the gut microbiota and promote cognitive function and brain health. This is what emerges from a recent scientific research published in the journal Nutrients by a Korean team (Park et al, Nutrients, 2020).
Diet and depression
Depression is a condition that is accompanied by sadness, lack of motivation, fatigue and poor concentration. Diet can play a role in both worsening depression and helping to improve depression. In fact, a diet rich in sweets, red and processed meats, high-fat dairy products and low in fruits and vegetables has been observed to increase the risk of depression. Conversely, flavonoids, which are antioxidants found in fruits, vegetables, tea and cocoa, have been shown to increase blood flow to the brain, thereby improving cognitive function, and reducing the risk of depression. Juices obtained from fruit and vegetables, such as orange juice, are also rich in flavonoids, such as, for example, hesperidin and narirutin. However, the action of fruit juices, including commercial ones, on health and the brain has not yet been evaluated in depth. This is certainly a shortcoming as the juices are easy to integrate into the daily diet and are tasty.
Orange juice against depression? Here is the experiment
Therefore, in order to fill this gap, Korean scientists have developed research. They recruited 40 people, between the ages of 20 and 30. The volunteers were divided into two groups. The first group was asked to drink 380 ml of orange juice, rich in flavonoids, every day for two months. The second group took 380 ml of orange-flavored juice, low in flavonoids, every day for two months. At the beginning and at the end of the experiment, the volunteers were subjected to analyses, in order to measure the blood markers of the health of the microbiota, and to tests, in order to assess the presence of depression and any improvements.
Orange juice modifies the microbiota and fights depression
At the end of the study it was found that orange juice rich in flavonoids increased the values of the cerebral neutrophic factor or BDNF. BDNF is a protein of the neutrophin family that participates in numerous functions of the central nervous system and also in the therapeutic processes triggered by antidepressant drugs. It has been observed that those with major depressive disorders also have low BDNF values. Not only that, even the tests aimed at evaluating the presence of depression showed improvements in those who had taken the orange juice rich in flavonoids. These effects are linked to the changes made by the flavonoids in orange juice at the microbiota level. In fact, the integration of orange juice has been able to increase the values of some bacteria such as Lachnospiraceae, important producers of butyrate, which in turn is anti-inflammatory and strengthens the intestinal mucosa. And we know that the gut and the brain are connected and that a well-functioning gut is also capable of reducing the risk of depression.
The orange juice used in the experiment is of those found in the supermarket. So, orange juice, whether you buy or prepare it at home, is certainly a healthy choice to integrate into your daily diet to improve cognitive function and keep sadness and depression away.