A common spice already enjoyed by many Americans appears to lower blood sugar and cholesterol, a potential boon to millions of people with diabetes and millions of others with high cholesterol.
The spice is cinnamon. In a paper published in December in Diabetes Care, researchers from the Beltsville Human Nutrition Research Center in Maryland, part of the US Department of Agriculture, reported on a small, but encouraging study of 60 people with Type 2 diabetes in Pakistan.
It showed that as little as one gram a day of cinnamon -one-fourth of a teaspoon twice a day – can lower blood sugar by an average of 18 to 29 percent, triglycerides (fatty acids in the blood) by 23 to 30 percent, LDL (or “bad”) cholesterol by 7 to 27 percent and total cholesterol by 12 to 26 percent.
Although some scientists suspect that cinnamon may be toxic at very high doses, at the small doses used in this study, the spice appears to be safe, said Richard Anderson, (CQ) the lead scientist in the Beltsville lab and senior author of the paper.
To be sure, one small study on 60 people and a handful of other studies on the biochemistry of cinnamon in cells in lab dishes provide far too little data to recommend that Americans immediately start wolfing down large quantities of the spice. On the other hand, the USDA study was “impressive,” said Melinda Maryniuk (CQ) , a senior dietician at the Joslin Diabetes Center in Boston. Cinnamon “can’t harm in small doses, it may help, and it’s not adding calories,” she said.
She warned, however, that people with Type 2 (or adult-onset) diabetes should monitor their blood sugar more frequently if they take cinnamon because it could intensify the effects of diabetes medications, including insulin.
Alice Lichtenstein (CQ), a professor of the Friedman School of Nutrition Science and Policy at Tufts University, added another caveat: Don’t use the news on cinnamon to indulge regularly in calorie-laden cinnamon buns or muffins.
Scientists already have a pretty good, albeit incomplete, idea of how cinnamon may work, at least in diabetes, said Don Graves (CQ) , an adjunct professor of biochemistry at the University of California in Santa Barbara and a guest investigator at the Sansum Diabetes Research Institute, also in Santa Barbara.
An active, water-soluble ingredient in cinnamon, proanthocyanidin (cq) , part of a family of chemicals called polyphenols that are often found in plants, somehow worms its way inside cells.
Once inside, it helps to phosphorylate, or activate, the part of the insulin receptor that sticks into the cell. (The other end of the receptor sticks out through the cell membrane into the bloodstream to catch molecules of insulin, which escort sugar to cells.)
Then, once the receptor is activated, whether by insulin or proanthocyanidin, a cascade of chemical reactions occurs so that the cell can use energy from sugar. Cinnamon, in other words, does much “the same thing as insulin,” said Graves.
“Cinnamon makes insulin more efficient,” added Anderson of the USDA. In diabetes, the problem is that insulin no longer does a good job of escorting sugar into cells. Cinnamon “makes cells more sensitive to the insulin that is available. And if you improve insulin sensitivity, you improve blood lipids. Insulin is the driver.”
Dr. Frank Sacks (CQ), a physician at Brigham and Women’s Hospital and professor of nutrition at the Harvard School of Public Health, is cautious. “There are certainly substances in plants that have very strong biological effects, so the concept is fine,” he said. And plant derivatives “are being intensively researched at many places – that’s a hot topic.”
But people should not rely on cinnamon to replace statin drugs, used by 20 million Americans to lower cholesterol. “Cinnamon is a lot less effective than statins,” he said. Statins were tested in rigorous studies on 70,000 people for five years or more.” Compared to that, the research on cinnamon is weak. It’s also curious, he said, that the USDA study found that the beneficial effects of cinnamon lasted for at least 20 days after people stopped taking it. “I don’t know of any drug or product whose effects persist for 20 days.”
On the other hand, Dr. Andrew Greenberg, director of the obesity metabolism laboratory at Tufts, has reviewed the existing literature on cinnamon and is impressed enough to be starting a collaboration with Anderson, whose preliminary findings he described as “very exciting and promising.”
One note of caution is that coumarin, a substance found in cinnamon, may trigger cancer in animals. Cinnamon also contains cinnamaldehyde, which is toxic. But these toxic components are fat-soluble, while the beneficial ingredient, proanthocyanidin, is water-soluble. Water-soluble extracts of cinnamon are available in which “all the bad components are left behind,” said Anderson. (Ground cinnamon does allow both water- and fat-soluble components to be absorbed, but at the doses recommended, it does far more good than harm, he said; cinnamon sticks placed in hot water release only water-soluble components.)
It’s easy to add cinnamon to the diet, by sprinkling at bit of powder on cereal or coffee or soaking a cinnamon stick in a cup of tea. In fact, noted Anderson, one of his colleagues who did not have diabetes was able to lower his blood sugar just by using a cinnamon stick regularly in tea.
There may be an indirect health benefit to be had from cinnamon, too, according to Taiwanese scientists writing in the July 14 issue of Agriculture and Food Chemistry. Cinnamon oil, they found, kills mosquito larvae more effectively than DEET, a common pesticide and mosquito repellent. The next step is to test it against adult mosquitoes.