Victorian researchers are conducting what is believed be the world's first clinical study of whether an improved diet can help people suffering from major depression.

Scientists at Deakin University, St Vincent's Hospital and Barwon Health are recruiting 200 people in Melbourne and Geelong to take part in the study.

Associate Professor Felice Jaka says the researchers will look at whether a Mediterranean and red meat diet can alleviate depressive symptoms.

"Diet quality seems to be related to the risk of depression and anxiety," she said.

"But of course a different question is if you're already depressed, does improving your diet actually help?

"The Mediterranean diet is very healthy and that's one that has lots of plant foods and vegetables and fruits, wholegrains and fish but our research has indicated that red meat may also be important."

However, Associate Professor Jaka says it is unlikely a change of diet would form the primary treatment of depression.

"Anti-depression medications are very helpful to many people and very important to take but for some people they're not effective so we certainly wouldn't see this as an either-or," she said.

"We would see this very much as supporting any other sort of therapy that people may be on but for some people it actually may be enough in and of itself.

"It's one of the things we'll be looking at."