It’s no wonder consumes are confused about what to eat or drink to stay healthy. Consider the following two headlines, which recently appeared side by side on the front page of the Health section of cnn.com: "Study: A little wine may keep mind sharp" and "Study: Even one drink can impair thinking."

Both studies examined the effects of alcohol on the brain, but while the first looked at the long-term effects of drinking a little wine each day, the second examined the acute effects of even a single drink.

Beginning in the 1970s, researchers at the Institute of Preventive Medicine at Kommunehospitalet in Copenhagen, Denmark interviewed 1,700 people about their eating and drinking habits. After 15 years, study participants were checked for Alzheimer's disease and other forms of dementia. They concluded that people who drank just one glass of wine per day were less likely to develop dementia than those who did not drink wine. The same was not true of beer drinkers, however, who actually had a higher risk of dementia.

Still, researchers urge caution. “These results don't mean that people should start drinking wine or drink more wine than they usually do," said Dr. Thomas Truelsen, lead researcher, in a written statement.

In the second study researchers at the University of Amsterdam and Leiden University put sensors on the scalps of 14 men to track brain changes that occur after drinking one or several drinks or a placebo. The volunteers then took a computer test requiring quick thinking and instinctive reasoning.

After drinking the placebo, the average error rate for the test was less than 5 percent. After just one drink, the error rate increased to nearly 20 percent and the time it took to answer each question also increased. Researchers concluded that even small amounts of alcohol were enough to diminish one's ability to make quick decisions and detect errors.