Dietary changes over the last 50 years may be fuelling the rise of mental illness, new research has claimed.
The Mental Health Foundation along with food campaigners Sustain said the way food is now produced alters the balance of key nutrients.
The last 50 years has also seen people eating less fresh food, and more saturated fats and sugars, all of which is leading to depression and memory problems, their study claimed.
Dr Andrew McCulloch, chief executive of the Mental Health Foundation, said: "We are well aware of the effect of diet upon our physical health. But we are only just beginning to understand how the brain as an organ is influenced by the nutrients it derives from the foods we eat and how diets have an impact on our mental health."
He said that addressing mental health issues with diet was having better results than drugs or counselling, in some cases.
The report, Feeding Minds, pointed out the delicate balance of minerals, vitamins and essential fats consumed had changed in the past five decades.
According to the research, the intensification of farming and production had introduced pesticides and altered the body fat composition of animals.
The report said people were eating 34 per cent less vegetables and two-thirds less fish - the main source of omega-3 fatty acids - than they were 50 years ago.
Such changes, the study said, could be linked to depression, schizophrenia, attention deficit hyperactivity disorder (ADHD) and Alzheimer's disease.
The two groups urged people to adopt healthier diets, with more fresh vegetables, fruit and fish, and called on the government to raise awareness about the issue.
However, food experts said the results of such research were subjective and the study of nutrients effect on mental health was still in its infancy, making it difficult to draw any conclusions.