Coffee may prevent depression, scientists say

Women who drink two or more cups of coffee a day are less likely to get depressed, research suggests.

Coffee must contain caffeine to have the effect, say the researchers

It is not clear why it might have this effect, but the authors believe caffeine in coffee may alter the brain's chemistry. Decaffeinated coffee did not have the same effect.

The findings, published in Archives of Internal Medicine, come from a study of more than 50,000 US female nurses.

The experts are now recommending more work to better understand the link.

And they say it is certainly too soon to start recommending that women should drink more coffee to boost mood.

Caffeine lift
The Harvard Medical School team tracked the health of the women over a decade from 1996 to 2006 and relied on questionnaires to record their coffee consumption.

More of these women tended to be non- or low-coffee drinkers rather than frequent coffee consumers.

Compared with women who drank one cup of caffeinated coffee or less per week, those who consumed two to three cups per day had a 15% decreased risk of developing depression.

Those who drank four or more cups a day cut their risk by 20%.