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There is new evidence that a healthy diet rich in fruits and vegetables and limited to processed foods may help alleviate depression symptoms. In a group of young adults, depression decreased significantly after being medicated for three weeks Had eaten kind. Participants saw that their depression "score" dropped from the "moderate" to the "normal" range, and they also reported a lower level of anxiety and stress.
Alternatively, depression did not move in the control group of participants who did not change their diet. These participants continued to benefit more from refined carbohydrates, processed foods and sugary foods and beverages. Their depression levels remained in the "medium severity" range.
"We were pretty surprised at the results," researcher Heather Francis, a lecturer in clinical neuropsychology at Macquarie University in Sydney, Australia, told us by email. "I think the next step is to demonstrate the physiological mechanism that underlies the improvement of dietary depression," says Francis.
Scientists learn more about how poor nutrition can increase inflammation, and this can be a risk factor for depression. "Highly processed foods increase inflammation," says Francis. "If we do not eat enough nutrient-rich foods, it can lead to nutritional deficiencies that also increase inflammation," she says.
In this study, participants of the Healthy Eating arm of The Study consumed about six servings of fruits and vegetables more per week than the control group. Participants, "who had a greater increase in fruit and vegetable intake, showed the greatest improvement in depression symptoms," says Francis.
Participants were also instructed to increase the consumption of whole grains to the recommended three servings per day and three servings of lean meat, poultry, eggs, tofu and beans. In addition, they were advised to take three servings of fish per week.
For dairy products, three servings per day were recommended, unsweetened. Participants were also instructed to consume three tablespoons of nuts and seeds per day and two tablespoons of olive oil per day, and were advised to add spices, including turmeric and cinnamon.
One of the shortcomings of nutrition science is that they are often reliant on a request to remember what they have eaten in the past. Considering our faulty memories, these actions can be unreliable. However, this study included a clever way to check how many people were consuming fruits and vegetables. The participants' palms were scanned with a spectrophotometer. The device can detect the degree of yellowing in your skin that correlates with the ingestion of carotenoids that you receive from eating fruits and vegetables.
The researchers used several research questionnaires to assess participants' mental health, including one asking them how often they had symptoms of depression in the previous week.
The new study complements a growing body of research that highlights the link between nutrition and mental health. "We have a very consistent and comprehensive evidence base around the world that links healthier diets with reduced risk of depression," said Felice Jacka, professor of nutritional psychiatry and epidemiological psychiatry at Deakin University's Food and Mood Center in Australia.
A 2013 meta-analysis of 22 previously published studies found that the Mediterranean diet is associated with a lower risk of depression.
Similarly, a study from 2017 found that a diet rich in fruits, whole grains, vegetables, fish, olive oil and low-fat milk is associated with a lower risk of depression while eating a rich diet Refined cereals, sweets and high fat dairy products were associated with a higher risk of depression.
These relationships between diet and depression are independent of other disturbing factors such as "education, income, body weight, and other health behaviors," notes Jacka, who is also president of the International Society for Nutritional Psychiatry Research. And "this applies to all countries, cultures and – above all – age groups," Jacka adds in an e-mail.
"The area is certainly very exciting," says Jerome Sarris, professor of Integrative Mental Health at the NICM Health Research Institute at Western Sydney University in Australia.
Most of these studies, however, show an association and "can not imply a cause," warns Sarris. In other words, the studies do not prove that changes in diet directly cause the improvement or decrease in mood.
It's difficult to figure out how diet changes can help improve mental health. Although this new study was a randomized controlled trial considered to be the gold standard in medical research participants knew that they were part of the group that was supposed to eat healthy foods. And there are many studies that prove that people who say that they are doing something that makes them less depressed actually report less depression. This is known as the placebo effect. Unlike in a drug study, there is no way in a diet study to "dazzle" participants so they do not know if they are receiving "medicine" or "placebo."
"We need more mechanistic studies to understand how nutrition affects mental and spiritual health," notes Jacka.
In addition to inflammation, there is also some tentative evidence from animal studies that suggests that gut microbiota may affect brain function and therefore mental health – for example, by altering the neurotransmitter serotonin, which is largely synthesized by gut bacteria.
Further studies are needed to understand these relationships in humans and to develop targeted interventions for people with various mental illnesses, Jacka notes.
Nonetheless, mental health professionals should consider considering their patients' diet and lifestyle a routine part of their care. Drew Ramsey, psychiatrist at Columbia University. "We have to talk to mentally ill patients about what they eat," says Ramsey. "As people strive to look after themselves and adhere to a belief system that they believe is good for them, their mental health will improve." He teaches a medical training course for care providers who want to learn more about incorporating nutrition into their practice.
Although diet may be important to our mood and mental health, it is unlikely to be a panacea for the treatment of mental disorders, notes Sarris.
"Nutrition is certainly part of the picture, but also physical activity, good psychological care, medication (if necessary) … adequate sleep, adequate contact with nature and balanced lifestyle," he says. "My general takeaway message is about an inclusive approach."