The chatty coffee-shop employee's comment confused me. I had paused at the condiment station to add a sprinkle of cinnamon* to my cappuccino, and he was wiping down the counter in front of me.
"Ah, yes, for your eyes?" he asked, gesturing at the cinnamon shaker.
"My...eyes?" I fumbled in response. "No, for my coffee..."
He gave me a pitying smile, informed me that "everyone knows" cinnamon is good for ocular health, and went back to cleaning.
As a bit of Googling revealed, he's not the only one who believes in cinnamon as a health product. It's sold in many nutritional supplements and homeopathic remedies, marketed with claims that range from boosting metabolism to controlling blood sugar to, yes, enhancing vision.
I don't see (pardon the pun) hard evidence for most of those claims, but a 2006 German study reported that cinnamon could help stabilize insulin levels for people with Type 2 diabetes, and a study published this year in the Journal of the American College of Nutrition supports the idea that dietary cinnamon compounds "could reduce risk factors associated with diabetes and cardiovascular disease."
Today, cinnamon was in the news again as the USDA's Agricultural Research Service (ARS) reported that it may help prevent or reduce brain swelling.
When the brain is temporarily deprived of oxygen and food (glucose)—as in the case of a traumatic injury or stroke—brain cells tend to swell, which can cause permanent neurological damage. But in a lab experiment conducted by scientists at the ARS Human Nutrition Research center in Beltsville, Maryland, isolated brain cells that were exposed to a cinnamon polyphenol extract did not swell.
However: "The researchers caution that table cinnamon compounds may accumulate in the body and should not be ingested consistently as more than a spice over long periods of time."
In other words, I should stick to just sprinkling it on my cappuccinos and apple crisp for now. But, as a scientist I interviewed a while ago about pepper-based fungicides for wine grapes said, nature may hold the answers to many human and plant health problems—right under our noses.
*Like most of the ground cinnamon sold in supermarkets, this was probably cassia, not Ceylon cinnamon, which some people call "true cinnamon." I just checked with one of the ARS researchers, Richard Anderson, and he says they've tested several types of cinnamon, including cassia, and all proved effective.