For women older than 65, drinking that extra cup of joe may protect thinking and memory skills, according to a new study published Monday in the journal Neurology.
Women who drank more than three cups of coffee -- or the equivalent amount of tea -- per day showed less decline in performance over time on memory tests than women who drank only one cup or less of coffee.
"We looked at the relationship between coffee drinking and cognitive decline, and we found that there was a relationship," said Karen Ritchie, an epidemiological and clinical researcher at La Colombiere Hospital in Montpellier, France. "It was clear -- the more coffee, the less the decline. We then had to adjust for other factors, and we found that the more we adjusted, the greater the effect."
The study observed 7,000 people over age 65 whose memory skills and caffeine consumption were monitored for four years. Since most people get their daily dose of caffeine in a cup (or three) of coffee, the number of times participants enjoyed this beverage daily was used as a measure of how much caffeine they took in daily -- though the chemical also exists in tea, soda, chocolate and other foods in smaller amounts.
The researchers found that not only did heavy coffee-drinkers have less memory decline, but the benefits increased with age. Women over the age of 80 who drank four or more cups of coffee were 70 percent less likely to have a decline in memory.
The benefits of increased coffee intake are significant for women, but caffeine's mind-preserving effects were not seen in men, causing researchers to wonder why.
The researchers said that although they are not sure exactly how caffeine, a stimulant, seems to decrease memory loss, they think it may put the brakes on the chemical changes in the brain that are thought to eventually lead to Alzheimer's disease.
This study observed 7,000 people over age 65 for four years. Since this is a huge number of sample and a long time period study, there might be a lot of participants who forgot to record their consumption of coffee daily and correctly. Also, there is no control group. They just compared people's memory skills and caffeine consumption in the same sample. They need to observe those who do not drink any kind of caffeine at all for more concrete result. They don't explain why women show more significant benefits than men and why the benefits increased with age. They need to conduct more experiments with men group and different age groups so that they can infer the reason why the benefits are different according to sex and age.