Eating tomatoes just a few times a week could halve the chances of suffering depression, a study claims.
Researchers analysed the mental health records and diet habits of just under 1,000 men and women aged 70 or over.
The results found those eating tomatoes two to six times a week were 46 per cent less likely to suffer the blues than those eating them less than once a week.
But other fruits and vegetables do not have the same benefits, the study found.
Eating healthy foods like cabbage, carrots, onions and pumpkins appeared to have little or no effect on psychological well-being.
Up to 20 per cent of people suffer depression at some point in their lives, with women affected more than men.
The elderly are at high risk because of the effect on mood from declining health, bereavements and loneliness.
Tomatoes are rich in antioxidant chemicals that are thought to protect against some diseases.
They are a particularly good source of lycopene, an antioxidant that gives them their deep red colour and has been linked with reducing the risk of prostate cancer and heart attacks.
British consumers get through half-a-million tonnes of tomatoes every year – the equivalent of 19 pounds per person a year.
However, this is still much less than in some Mediterranean countries.
A team of researchers from China and Japan, led by Dr Kaijun Niu from China’s Tianjin Medical University, wanted to investigate preliminary reports that lycopene might also promote psychological and well as physical health by reducing oxidative stress, or damage to healthy brain cells.
They analysed the mental health records and dietary habits of just under 1,000 elderly Japanese men and women aged 70 or over.
The results, published in the Journal of Affective Disorders, found those eating tomatoes two to six times a week were 46 per cent less likely to suffer depression than those eating them less than once a week.
Eating tomatoes every day slashed the risk by 52 per cent.
But there was no obvious advantage to mental health from other vegetables.
The researchers said they cannot be sure if lycopene in tomatoes directly affects the mind, or whether it simply protects against the depression caused when people develop potentially fatal diseases like cancer.
In a report on the findings they said: ‘These results suggest that a tomato-rich diet may have a beneficial effect on the prevention of depressive symptoms.
‘In contrast, no relationship was observed with intake of other kinds of vegetables.’