Recent research suggests that the classic Western diet with its many industrially-processed, fatty foods causes an increasing number of depressive and anxiety disorders. Unhealthy eating promotes inflammatory processes in the body and may contribute to a range of neurological and psychiatric disorders. A study conducted at the University of Pittsburgh with 247 participants showed that with a diet consisting mainly of tuna, salmon, olive oil, avocado and sweet potatoes, the participants showed far fewer depressive symptoms than the other group of test subjects, most of whom preferred industrially-processed foods.
More and more neuroscientists are recognizing the complex ways in which our food intake is related to brain health. A large number of studies have already been conducted and the list of foodstuffs that are supposed to be the right “food” for our brain is getting longer and longer – fish and the Omega 3 fatty acids, for example, are at the top of the list when it comes to preventing psychoses and depression. Lactic acid bacteria in fermented foods such as yogurt, pickles and sauerkraut appear to help alleviate anxiety and worry, while foods rich in antioxidants such as green tea and fruit can help keep dementia and Alzheimer’s at bay. One or two comparative studies are of course still required to clarify and supplement these findings. However, the most certain evidence to date is that the so-called Mediterranean diet of fruit, vegetables, fish, lean meat, olive oil and a glass of red wine every now and then is refreshment for the brain. In Western cuisine, on the other hand, frozen pizza, packaged soups and canned food are often on the table. According to a representative survey by the German Federal Ministry of Food and Agriculture, 20% of German households cook their own meals “actually never” or “at most once a week” – and 47% of German men and 22% of German women eat meat every day, which the experts also regard as being problematic.
In a study published in 2015, scientists even found evidence that poor nutrition “shrinks” the brain. The psychiatrist Felice Jacka, together with colleagues from Deakin University and the University of Melbourne in Australia, analyzed data from a longitudinal Australian study on mental health. At the start of the study, the subjects were between 60 and 64 years old, gave detailed information about their eating habits and underwent a brain scan. Their brains were scanned again four years later, and the focus was on the hippo-campus – which is considered the center of our memory. We also know that the hippo-campus shrinks with increasing age. The study results clearly showed that the left hippo-campus had become much smaller in the test persons who preferred hamburgers, steaks, french fries and soft drinks and declined fruit and vegetables, compared to those of test persons of the same age group who mostly preferred Mediterranean food.
The researchers are still not quite sure exactly which mechanisms are behind these findings. According to science, inflammatory processes could be one of the triggering factors. A high sugar content diet in particular promotes metabolic changes and inflammation in the body and several studies have shown that these inflammatory processes play an important role in brain diseases.
Epidemiologist Martha Morris and her team at Rush University in Chicago established similar relationships between nutrition (Mediterranean and low-salt) and cognitive decline in old age. In the observational study, 960 older people were asked about their eating habits and their mental fitness was regularly checked. Five years later, participants who said they often ate vegetables, berries, nuts and olive oil and little fried, fast food and red meat were less frequently diagnosed with Alzheimer’s disease. In the mental test, they also scored as well as subjects who were 7.5 years younger, but who had eaten unhealthy food.
Conclusion: A healthy diet combined with exercise and mental activity can help keep the “grey matter” fit longer in old age.
1. Jacka, F.N. et al.: Western Diet is Associated with a Smaller Hippocampus: A Longitudinal Investigation. In: BMC Medicine 13,215, 2015
2. Morris, M.C. et al.: MIND Diet Associated with Reduced Incidence of Alzheimers’s disease. In: Alzheimers’s & Dementia 11, P. 1007-1014, 2015
3. Sarris, J. et al: Nutritional Medicine as Mainstream in Psychiatry. In: Lancet Psychiatry 2, P. 271-274, 2015