It seems there is no end to the health benefits that can be gained from following a Mediterranean style diet. Not only has the diet been linked to decrease risk of conditions such as heart disease, Type 2 Diabetes, some cancers, obesity and stroke, but also with improved mental health.
The Med diet is based on the traditional eating style of the people of the Mediterranean coast in countries such as Italy, Spain and Greece. The diet is rich in fruit, vegetables, legumes, grains, nuts, seeds and fish. It also promotes the use of olive oil and moderate wine consumption. The diet is high in vitamins, fibre, minerals, healthy unsaturated fats and antioxidants and is thought to one of the healthiest diets in the world.
Studies have shown that the Med diet may have beneficial effects for a number of mental health conditions, including depression, Alzheimer’s and dementia.
Diet and Mental Health
Although we are well aware of the physical effects of a healthy or unhealthy diet on the body, the effects on the brain are still on their way to being completely understood. It is thought that the change in dietary intake over the last 50 years in western countries may be a key factor in deteriorating levels of mental health and development of conditions such as Alzheimer’s, Schizophrenia and ADHD.
Changes in industrial farming, such as increased fat content in chickens, have altered the balance of omega- 3 and omega- 6 fatty acids present in our diets, and it is thought that these are essential for brain function. Saturated fat intake has also increased dramatically, which researchers feel may be negatively associated with brain function. We are also eating 34% less vegetables and two thirds less fish than 50 years ago, (the main source of omega-3 fatty acids) which could be linked to ADHD, schizophrenia and particularly depression, according the a study carried out by the Mental Health Foundation in the UK.
Schizophrenia sufferers have been shown to have lower levels of polyunsaturated fatty acids, whilst some studies have suggested that high vegetable consumption can protect against Alzheimer’s disease. Children with ADHD have also frequently been shown to have low iron and fatty acid levels. It seems that there is a clear link between dietary intake and mental health, particularly with foods that are the basis of the Mediterranean diet such as fish, vegetables and olive oil.
The Med diet and depression
In 2009, a study carried out by the University of Navarra in Spain found that there was an association between eating a healthy Mediterranean diet and reduced development of depression. Over 10,000 Spanish subjects, all of whom were free of depression at the start of the study, were followed for four and a half years. At the start of the study the participants filled in a food intake questionnaire and were assigned a score according to how close their diet was to a Med style eating plan. Those who reported a diet most similar to the Med diet were found to be more than 30% less likely to develop depression.
The study suggested that the foods that were linked to a lower risk of depression included nuts, legumes, fruits and a high level of monounsaturated fats (such as those found in olive oil), compared to saturated fats (found in butter). However, it is thought that the overall diet composition is more important than individual foods. It is possible that the combination of omega three fatty acids from fish, along with other unsaturated fats and antioxidants from olive oil and nuts, flavanoids from fruit and large amounts of B vitamins may contribute to a protective effect.
It is not completely clear why this association was found, however it is believed that a deficiency of essential vitamins and other nutrients in the diet may prevent the body from synthesising the neurotransmitters in the nervous system correctly. As the membranes of neurons are made of fat, it is also possible that the type of fat has an influence on the formation of these membranes. The Med diet, being high in essential nutrients and unsaturated fats could prevent these deficiencies. Another theory is that antioxidants, that repair cell damage caused by free radicals, may also help fight depression.
The Med Diet, Alzheimer’s and Dementia
A number of studies have shown that people following a Med style diet are less likely to develop Alzheimer’s disease. In 2006 , a study performed by Columbia University Medical Centre suggested those with eating patterns more similar to the Med diet have about 40% less risk of developing Alzheimer’s. Similar findings were reported in a French study, where men and women were both found to have slower age related decline in cognitive function when they followed a Med style eating pattern. It was also found that exercise played a part in reducing the risk of Alzheimer’s by up to 67%. This is also in line with the Mediterranean philosophy which promotes physical activity.
Again, it is unclear why this effect is seen. However, it is speculated that controlled blood sugar levels, decreased inflammation in the body, healthier blood vessels and reduced levels of unhealthy blood cholesterol , all of which are associated with the Med diet, may all play a part in the slowed progression of dementia.