An apple a day keeps the doctor away. It may also keep your depression at bay, according to a new study. New research from the University of Warwick's Medical School shows that eating five portions a day of fruits and vegetables is associated with happier moods.

The research study was published on September 19 in the journal BMJ Open. It followed approximately 14,000 adults over the age of 16, about half male and half female. All participants in the study lived in England. The study tracked the participants' mood and psychological state using the Warwick-Edinburgh Mental Well-being Scale. The researchers also tracked the diet, BMI and smoking intake of the participants.

Things like having too high of a BMI, smoking more and eating fewer portions of fruits and vegetables were associated with worse moods and poor mental well-being, the study showed. The study found, however, that although obesity and moderate alcohol consumption were associated with low mental well-being, there was not a correlation between BMI or alcohol consumption and high mental well-being.

The lifestyle factors that contributed the most to happiness included eating more portions of fruits and vegetables, and not smoking. This was consistent for both genders, in men and women. About a third of the participants with high mental well-being ate five or more portions of fruits and vegetables a day. Only about 6 percent of those with high mental well-being ate one or fewer portions of fruits and vegetables daily.

"The data suggest that higher an individual's fruit and vegetable intake the lower the chance of their having low mental well-being," said Dr. Saverio Stranges, the lead author of the study.

This means that if you want to keep away those blues, you should consider eating more fruits and vegetables, Dr. Stranges said. There is already a lot of evidence from past studies that fruit and vegetables are also associated with good physical health.

"Our findings add to the mounting evidence that fruit and vegetable intake could be one such factor and mean that people are likely to be able to enhance their mental well-being at the same time as preventing heart disease and cancer," said Professor Sarah Stewart-Brown, a co-author on the paper.

Another study published earlier this week showed that eating a diet high in whole foods like fruit, vegetables and legumes, was one of the major factors in preventing heart attacks in men. So eat those extra brussel sprouts at dinner - it'll help keep that smile on your face and your mental and physical health in good shape.