According to new research released this week, mental health is linked to diet and changes to diets over the last 50 years may hold the key to the rise of mental illness.
The findings support a growing body of evidence that food can have an effect upon a person’s mental health and behaviour that is both immediate and long lasting because of the way it affects the structure and function of the brain.
Food campaigners Sustain and the Mental Health Foundation say the way food is now produced has altered the balance of the key nutrients people consume.
The report 'Feeding Minds', published by the Mental Health Foundation (MHF) and Sustain, suggests that some foods damage the brain by releasing toxins or oxidants that harm healthy brain cells.
It says that an unbalanced diet that fails to include adequate amounts of complex carbohydrates, essential fats, amino acids, vitamins and minerals and water can lead to mental ill-health.
Over the last five decades the UK population has eaten less fresh food and more saturated fats and sugars, this say the researchers leads to depression and memory problems.
However not all experts agree and some regard the research as inconclusive, while others agree that diet has an affect on physical health.
Some experts say that addressing mental health problems with changes in diet was showing better results in some cases than using drugs or counselling.
The report says the balance of minerals, vitamins and essential fats consumed has changed in the past five decades.
According to the researchers the industrialisation of farming has introduced pesticides and has altered the body fat composition of many animals due to the diet they are now fed.
As an example, the report points out that chickens reach their slaughter weight twice as fast as they did 30 years ago, increasing the fat content from 2% to 22%.
Their diet has also altered the balance of vital fatty acids omega-3 and omega-6 in chickens, which the brain needs to ensure it functions properly.
In direct contrast, consumption of saturated fats has steadily increased with the availability of readymade meals and access to fast food; saturated fats are known to slow down the brain's working process.
The researchers say that unequal intakes of the two different types of fat are implicated in mental health problems, and suggest that the Western diet now includes too much omega-6 and insufficient omega-3.
The report says people are now eating 34% less vegetables and two-thirds less fish, the main source of omega-3 fatty acids, than they were 50 years ago.
The study says such changes could be linked to depression, schizophrenia, attention deficit hyperactivity disorder (ADHD) and Alzheimer's disease.
They urge people to adopt healthier diets, with more fresh vegetables, fruit and fish, and are calling on the government to raise awareness about the issue.
The report makes 14 key recommendations aimed at government departments and a range of other stakeholders which are in line with recommendations for good health advocated by all health professionals.