Researchers suggest that all adults, not just
diabetics, may benefit from its health effects
By Aaron W. Jensen, Ph.D.
Scientists and consumers alike are discovering that there is a tighter link between diet and health—especially in aging populations—than was previously suspected. Although it has long been known that fruits, vegetables, and grains are excellent sources of the vitamins and minerals that are so essential to good health, we continue to learn about the importance of supplementing our diets (no matter how healthful they may be) with additional amounts of certain nutrients.
The objectives of nutritional supplementation are fourfold:
- To compensate for the declining ability of our aging digestive systems to make certain dietary nutrients available to the rest of our bodies—thus preventing potentially harmful deficiencies.
- To compensate for our aging bodies’ declining ability to produce certain nutrient substances on their own—thus preventing potentially harmful deficiencies.
- To achieve above-normal levels of some nutrients so as to extract as much health benefit from them as possible—thus helping to prevent chronic diseases.
- In some cases, to benefit our bodies with valuable nutrients they would otherwise never encounter—thus enhancing our health, and perhaps even our longevity, in various ways.
It’s not just vitamins and minerals that occupy the spotlight of nutritional supplementation, but also certain amino acids and hormones, and a growing list of exotic phytochemicals—plant-based compounds that have beneficial effects on various aspects of our physiology. Many such compounds are found in the fruits, vegetables, and grains that we eat routinely, but many more are found in herbs and spices that we may eat only occasionally, or not at all. Antioxidant properties are a strikingly common feature in phytochemicals; they therefore play an important role in inhibiting aging processes related to oxidative damage caused by free radicals.
Cinnamon Mimics Insulin Function
Much scientific research has focused recently on the health benefits of herbs and spices. Some of these benefits are broad-based, but others are specific to one or a few physiological functions in the body. A good example is cinnamon, which may be of great value in maintaining healthy blood sugar levels, and cholesterol levels as well.
Because type 2 diabetes, or adult-onset diabetes, is a major public health concern (and not just for adults, but for children as well), Dr. Richard A. Anderson and his colleagues at the Human Nutrition Research Center of the U.S. Department of Agriculture screened extracts of a number of commonly consumed plants to see how well they could mimic the effects of insulin, a protein hormone that is responsible for regulating our blood sugar levels. From a selection of 49 culinary and medicinal plants, they found in laboratory tests that cinnamon was far more effective than any other plant in fulfilling insulin’s appointed role.1
It’s the MHCP in Cinnamon That Does It
Further research by Dr. Anderson’s group established that the active component in cinnamon responsible for its insulin-like activity is a water-soluble chemical compound called methylhydroxychalcone polymer, or MHCP. They found that MHCP was highly effective, providing essentially the same biological activity as insulin itself.2 It was effective not only in increasing the uptake of glucose (blood sugar) by cells, but also of stimulating the synthesis of glycogen, a polymeric form of glucose that is stored primarily in the liver and muscle tissues for use at times of peak energy demand, such as exercise. And MHCP turned out to be synergistic with insulin in these actions, providing a net effect greater than the sum of its parts.
The research in question was performed not on human beings, however, but on human adipocytes (fat cells) isolated in the laboratory. That’s a far cry from cells residing in a living, breathing—and perhaps diabetic—person. Would MHCP be as effective in a clinical trial with actual people?
Too Much Cinnamon May Be Unwise
That was the question addressed recently by a team of researchers in Pakistan, working in collaboration with Dr. Anderson in Maryland. They recruited 60 patients with type 2 diabetes (30 men and 30 women, average age 52, with an average disease duration of 7 years) to participate in a clinical trial.3 The patients were randomized into two groups: one for placebo and one for treatment with cinnamon, in daily amounts of 1, 3, or 6 grams. The duration of treatment was 40 days.
Oddly, the cinnamon used was not an aqueous extract of cinnamon bark (which would contain the MHCP as well as other water-soluble components), but rather whole powdered cinnamon bark, which of course contains MHCP along with every other component of the bark, water-soluble or not.* It’s odd because cinnamon contains significant amounts of coumarin, a well-known anticoagulant (blood thinner). Consuming relatively large (multigram) amounts of whole cinnamon on a daily basis could pose a health risk for some people, especially those who are already taking coumarin by prescription for therapeutic purposes. Consuming an aqueous extract of cinnamon poses no such risk, however, because coumarin is lipid-soluble, not water-soluble, and thus remains behind when the water-soluble components are extracted from the bark.
*The cinnamon used was derived not from the bark of the true cinnamon tree (Cinnamomum verum), but from the bark of the more abundant cassia tree (Cinnamomum cassia), which is the most commonly sold (and less expensive) form of cinnamon. It too contains MHCP as well as some of the same aromatic oils as true cinnamon, and thus has a similar flavor.
Despite the researchers’ claim that there were no problems (in this group of patients, at any rate) associated with the consumption of up to 6 grams per day of whole cinnamon powder, it seems unwise to consume that much cinnamon in the long term (not that many people would want to anyway, because too much of a good thing can soon wear thin). And MHCP’s availability as a nutritional supplement makes it convenient to obtain all the benefits without the potential liability of consuming too much cinnamon.
Cinnamon Sharply Reduced Blood Glucose Levels
But what are those benefits in human beings? That’s what the Pakistani-American study was designed to find out, so let’s see what the results were. The researchers measured the patients’ blood glucose and lipid levels (under fasting conditions) at the beginning of the study, and again at 20 days, 40 days (the end of the treatment), and 60 days (i.e., after a 20-day “washout” period following the cessation of treatment).
The results were dramatic: all three cinnamon doses had a strong impact on blood glucose levels—and on blood lipid levels as well, as we will see shortly. By contrast, the placebo had no significant effect on either measure. The glucose levels were reduced by 18–29% following 40 days of treatment. Whereas the highest dose (6 g/day) produced the most rapid response, the lowest dose (1 g/day) produced the most sustained response, i.e., a continued reduction in glucose levels even at the 60-day point; the reduction observed was 16%. The two higher doses produced slightly lower sustained responses, and they were judged not to be statistically significant.
How Does Insulin Work—and Not Work?
In type 2 diabetes, high blood sugar levels occur when glucose is prevented, to a significant degree, from entering cells of the body, notably liver, muscle, and fat cells. This is caused by a “short circuit” in the insulin signaling pathway, a cascade of highly specific chemical reactions that allow insulin to fulfill its role as the facilitator of glucose transport through the cell walls. Insulin is produced by the pancreas in response to elevated blood glucose levels; once it enters the blood, it signals the body’s cells to take up the excess glucose until normal levels are restored.
When insulin molecules bind to the insulin receptors on cell walls, tiny molecular “gates” open up and allow glucose molecules to pass through. If this system is impaired, the gates don’t respond adequately to the insulin signal, thus preventing the glucose from entering the cell. This condition, which is a common consequence of obesity, is called insulin resistance, and it’s both a harbinger and a symptom of diabetes. With insulin resistance, glucose levels in the blood remain high, a very dangerous condition in the long run. The pancreas tries to compensate by making more insulin, but this works only for so long. Eventually, the pancreas becomes overburdened and starts making less insulin. That’s when things go from bad to worse.
MHCP Increases Insulin Sensitivity
And that’s where cinnamon—or MHCP, to be specific—comes in. MHCP makes cells more responsive to insulin, i.e., it increases insulin sensitivity, the opposite of insulin resistance. Researchers in Japan found recently that when an aqueous extract of cinnamon (containing MHCP, of course) was given orally to laboratory rats, the insulin receptors on their skeletal muscle cells became more responsive.4 Enhanced insulin sensitivity means more glucose going into the cells, so the blood glucose levels fall, and biochemical order is restored.
Cinnamon Also Reduced Blood Lipid Levels
It turns out, as mentioned above, that cinnamon reduces blood lipid levels as well as blood glucose levels. In that same Pakistani-American study,3 the researchers measured the patients’ lipid levels, with the following results: total cholesterol was reduced by 12–26%; LDL-cholesterol (“bad cholesterol”) was reduced by 7–27%; HDL-cholesterol (“good cholesterol”) was unchanged; and triglycerides (fats) were reduced by 23–30%. All three doses of cinnamon were effective in reducing the levels of total cholesterol, LDL-cholesterol, and triglycerides, and all three showed remarkably sustained activity at the 60-day point (20 days after the treatment had stopped).
More Is Not Always Better
Despite individual differences in the effects produced by the different cinnamon doses at different time points, a striking fact emerged from all the data in this study: the 3-g/day and 6-g/day doses were no more effective, overall, than the 1-g/day dose in reducing blood glucose and blood lipid levels for the sustained period. Thus, it appears that the 1-g/day dose is not only sufficient to achieve the optimal benefits of cinnamon, it may be more than sufficient. Further research is planned to determine whether even lower doses are also effective.
An important point must be noted here. Whereas it seems almost certain, from Dr. Anderson’s own prior research, that MHCP was responsible for the reductions in blood glucose levels in this study, there was no indication of what component of the cinnamon powder was responsible for the reductions in blood lipid levels—not even whether it was a water-soluble or a lipid-soluble component. It would be interesting to know.
In any case, the researchers had the following to say:
In conclusion, cinnamon reduced serum glucose, triglyceride, total cholesterol, and LDL-cholesterol levels in people with type 2 diabetes. Because cinnamon would not contribute to caloric intake, those who have type 2 diabetes or those who have elevated glucose, triglyceride, LDL-cholesterol, or total cholesterol levels may benefit from the regular inclusion of cinnamon in their daily diet. In addition, cinnamon may be beneficial for the remainder of the population to prevent and control elevated glucose and blood lipid levels.
Spice It Up!
That’s a powerful endorsement for a common spice that is used the world over for its delightful flavor. Thanks to modern science, we have finally learned about some of the remarkable health benefits of this ancient substance, and the “secret ingredient”—MHCP—it has been harboring in its fragrant bosom for millennia. Although “methylhydroxychalcone polymer” may not roll trippingly off the tongue, it is a substance that probably belongs in every person’s larder of nutritional supplements. So spice up your life with a daily ration of MHCP. Your blood sugar will thank you for it.
References
- Broadhurst CL, Polansky MM, Anderson RA. Insulin-like biological activity of culinary and medicinal plant aqueous extracts in vitro. J Agric Food Chem 2000 Mar;48(3):849-52.
- Jarvill-Taylor KJ, Anderson RA, Graves DJ. A hydroxychalcone derived from cinnamon functions as a mimetic for insulin in 3T3-L1 adipocytes. J Am Coll Nutr 2001 Aug;20(4):327-36.
- Khan A, Safdar M, Khan MMA, Khattak KN, Anderson RA. Cinnamon improves glucose and lipids of people with type 2 diabetes. Diabetes Care 2003 Dec;26(12):3215-8.
- Qin B, Nagasaki M, Ren M, Bajotto G, Oshida Y, Sato Y. Cinnamon extract (traditional herb) potentiates in vivo insulin-regulated glucose utilization via enhancing insulin signaling in rats. Diabetes Res Clin Pract 2003;62:139-48.
Dr. Jensen is a cell biologist who has conducted research in England, Germany, and the United States. He has taught college courses in biology and nutrition and has written extensively on medical and scientific topics.
