He added, “And look, it’s chocolate. Who’s going to complain about chocolate?”

The findings support recent research linking flavanols, especially epicatechin, to improved blood circulation, heart health and memory in mice, snails and humans. But experts said the new study, although involving only 37 participants and partly funded by Mars Inc., the chocolate company, goes further and was a well-controlled, randomized trial led by experienced researchers.

Besides improvements on the memory test — a pattern recognition test involving the kind of skill used in remembering where you parked the car or recalling the face of someone you just met — researchers found increased function in an area of the brain’s hippocampus called the dentate gyrus, which has been linked to this type of memory.

“Boy, this is really interesting to see it in three months,” said Dr. Steven DeKosky, a neurologist and visiting professor at the University of Pittsburgh. “They got this really remarkable increase in a place in the brain that we know is related to age-related memory change.”

There was no increased activity in another hippocampal region, the entorhinal cortex, which is impaired early in Alzheimer’s disease. That reinforces the idea that age-related memory decline is different and suggests that flavanols might not help Alzheimer’s, even though they might delay normal memory loss.

But unless you are stocking up for Halloween, do not rush to buy Milky Way or Snickers bars. To consume the high-flavanol group’s daily dose of epicatechin, 138 milligrams, would take eating at least 300 grams of dark chocolate a day — about seven average-sized bars. Or possibly about 100 grams of baking chocolate or unsweetened cocoa powder, but concentrations vary widely depending on the processing. Milk chocolate has most epicatechin processed out of it.