Drinking two to seven glasses of wine per week can lower depression risk in middle-aged and older people, according to a Spanish study conducted by researchers from the University of Navarra.

The researchers arrived at the conclusion after surveying 5,500 light-to-moderate drinkers of both sexes over a period of seven years. None of the drinkers, aged 55 to 80, had suffered from depression or alcohol-related problems. Wine was the main alcoholic beverage drunk by those studied.

The participants' alcohol consumption, mental health and lifestyles were observed for up to seven years through annual visits, frequent medical exams, interviews with dieticians and questionnaires.

They found that people who drank two to seven glasses of wine a week were 32 percent less likely to suffer from depression than non-drinkers or people who drink more. The findings, published in BMC Medicine were the same for men and women.

"The results show an inverse association between low to moderate alcohol consumption and new cases of depression," said lead researcher Miguel Ángel Martínez-González of the University of Navarra. "Depression and heart disease seem to share some common mechanisms because they share many similar protective factors and risk factors."

"Lower amounts of alcohol intake might exert protection in a similar way to what has been observed for coronary heart disease," senior author Professor Martinez-Gonzalez, said. "In fact, it is believed that depression and coronary heart disease share some common disease mechanisms."

However, Martinez-Gonzalez also warned that depression prevention should not be the reason to start drinking.

"If you are not a drinker, please don't start drinking," Martinez-Gonzalez said. "If you drink alcohol, please keep it in the range of one or less drinks a day and consider drinking wine instead of other alcoholic beverages."

Drinking wine in moderation also lowers the risk of heart disease, diabetes, dementia and gallstones.