More Evidence for
on Blood Sugar
Study in prediabetic men and women shows
reduced glucose levels and systolic blood pressure
By Will Block
f you’re an American, you can count yourself lucky in more ways than you can count. In this great land of liberty (guard it well!), we still have freedoms and opportunities that most people in the world can only dream of.* It’s no wonder that so many of them want to come here and try to realize the American dream for themselves.
One thing that many foreigners notice when they come here is how terribly overweight we are as a society (just look around the next time you’re out and about). Not that they’re immune to obesity, especially if they’re from Europe or other prosperous, industrialized regions, but compared with us, they’re lightweights. As in so many other things, we Americans lead the way in the corpulence sweepstakes—and it’s killing us.
The Dark Side of Food
Obesity is by far the greatest risk factor for type 2 diabetes, the scourge that used to be called adult-onset diabetes until it started appearing in alarming numbers in our increasingly pudgy youngsters. Unless you’re unlucky in your genetic makeup, you can almost certainly avoid diabetes just by not becoming “supersized,” to use the junk food industry’s term for their calorie-bloated fare.
The trouble is that many of us don’t avoid becoming overweight. Putting on the pounds is the price we pay for the amazing abundance and attractiveness of our food—much of which is detrimental because of too much sugar and unhealthy fats—and the almost irresistible temptations it represents. But where excess food is the culprit, other foods—a spice and an herb in this case—can be saviors of sorts. More on those below.
Insulin Resistance—Key Factor in the
Before diabetes, in the physiological scheme of things, comes insulin resistance, a condition in which our cells gradually lose their sensitivity to insulin, the pancreatic hormone that regulates our glucose (blood sugar) levels. This can result, eventually, in hyperglycemia (chronically elevated glucose levels), the hallmark of diabetes. It’s also the primary cause of the many diabetic complications that damage tissues and organs throughout the body, including the nerves, blood vessels, heart, brain, kidneys, and eyes.
Insulin resistance is one of five medical conditions of which any three or more, if found together in the same person, constitute an even more pernicious condition called the metabolic syndrome. (It’s sometimes still called by the obsolete name syndrome X.) Think of the metabolic syndrome as a degenerative state that constitutes a fast track to serious, chronic diseases. It can be defined as a group of five major risk factors that are linked to insulin resistance and an increased risk of diabetes and cardiovascular disease. (For more on this subject, see
“Cinnamon and Chromium Counteract the Metabolic Syndrome” in the April 2008 issue.)
More than 50 Million Have the Metabolic Syndrome
Besides insulin resistance, the other four conditions that can contribute to the metabolic syndrome are: (1) visceral (abdominal) obesity; (2) high triglycerides (fats); (3) low HDL-cholesterol (the “good cholesterol”); and (4) hypertension (high blood pressure). Many people—not just older folks but also middle-aged and young adults—have all five of these conditions. And the metabolic syndrome is on the rise even among teenagers. Yikes!
Part of a crowd of about 50,000.
Imagine 1000 times as many, or 50,000,000.
According to the American authors of a recent study on the effects of cinnamon on the metabolic syndrome, the incidence of the syndrome in the United States is more than 26% of adults, or more than 50 million people. The authors also cite evidence that this dangerous condition increases the risk for atherosclerosis and cardiovascular disease up to 3-fold, and the risk for type 2 diabetes up to 5-fold.
Water-Soluble Cinnamon Extract Tested
Now let’s see what these researchers learned about the effects of cinnamon. First of all, they used a water-soluble cinnamon extract, not whole cinnamon powder, because the latter contains certain chemical compounds that can be deleterious in large amounts; those compounds are not soluble in water, so they’re absent from the extract. The subjects in the study were 22 prediabetic men and women, aged 30 to 60 (average: 46), who had features of the metabolic syndrome. After matching for age, fasting blood glucose levels, systolic blood pressure, and habitual physical activity levels, they were randomized into two groups for the double-blind, placebo-controlled trial.
For 12 weeks, the subjects were given 500 mg/day of either the cinnamon extract or placebo. According to the manufacturer, 500 mg of the extract is equivalent in biological activity to about 10 g of whole cinnamon powder and contains at least 1% by weight of procyanidins (type A), the compounds to which the biological activity is attributed. These compounds, which belong to a certain class of flavonoids, mimic some of insulin’s functions in important ways.*
Cinnamon Improves Glucose Regulation
At baseline (the beginning of the trial) and again after 12 weeks, the researchers took blood samples for comprehensive tests of metabolic function. They also measured the subjects’ body composition using a technique called dual-energy x-ray absorptiometry (DEXA), in which x-ray scans of the arms, legs, and trunk are digitized and fed into a computer for analysis. The computer calculates fat mass, lean mass, and bone mass; the percentage of body fat is then obtained by dividing the fat mass by the total scanned mass.
During the 12-week period, the subjects were instructed to maintain their usual diet and their current level of habitual physical activity so that the effects of the cinnamon extract would not be confounded by any changes in these factors. The results observed indicated modest but significant improvements in various measures. Systolic blood pressure was reduced by 3.8% (from 133 to 128 mmHg) in the test group, whereas it increased by 6.8%, for no apparent reason, in the control group. There were no changes in diastolic pressure or heart rate.
Most importantly, glucose regulation was significantly improved in the test group. After 12 weeks, their fasting blood glucose levels had decreased by 8.4%, while the control group showed an insignificant increase of 1.0%. Many other components of the subjects’ blood, including cholesterol and triglycerides, were also measured, but none of them showed any significant changes.
Four Trials in Four Countries
The improvement in glucose regulation observed in this study was significant in and of itself, but it was also significant vis-à-vis the results of other studies of a similar nature. In a recent article (“Cinnamon Improves Glucose Tolerance and Insulin Sensitivity,” January 2008), we discussed the impossibility of replicating clinical trials exactly, a problem that almost inevitably leads to somewhat different results, and sometimes to contradictory results, depending on how the many variables involved affect one another.
In that article, we summarized four clinical trials on the effects of cinnamon on blood glucose levels. The first, conducted with diabetic adults in Pakistan and published in 2003, showed good results with whole cinnamon powder in dosages of 1, 3, and 6 g/day; the authors concluded that the two higher dosages were no more effective than the lowest dosage. The second trial, conducted with diabetic adults in Germany and published in 2006, showed less pronounced, but still noteworthy, results with a water-soluble cinnamon extract that was equivalent to 3 g/day of whole cinnamon powder.
The third trial, conducted with postmenopausal diabetic women in the Netherlands and also published in 2006, showed no effects at all with 1.5 g/day of whole cinnamon powder. But the fourth trial, conducted with healthy young men in England and published in 2007, showed a distinct glucose-lowering effect in the oral glucose tolerance test with a 5-g capsule of whole cinnamon powder; the cinnamon was administered on a one-shot basis, in contrast with the previous studies, all of which entailed prolonged daily administration of cinnamon.
Improving the Cinnamon Statistics
Thus, three of the four trials showed a marked insulin-mimetic effect of cinnamon powder, resulting in improved blood glucose regulation. Only one of them, the Pakistani study, showed beneficial effects on cholesterol levels; the German and Dutch studies did not, and the British study did not measure cholesterol levels.
Now we can add to this list the study described above (conducted with prediabetic adults in the United States and published in 2006), which showed beneficial effects of cinnamon on blood glucose levels but not on cholesterol levels.
That brings our “cinnamon statistics” to four out of five studies that have shown positive results—or it would, but for the fact that a sixth study, conducted with diabetic adults in the United States and published in 2007 (and not discussed in our January 2008 article), showed no effect of cinnamon on blood glucose or lipid levels. The authors speculated that this might be because most (77%) of their subjects were taking antidiabetic medications, whereas the subjects in the successful Pakistani study were not. They neglected, however, to cite the successful German study, in which all of the subjects were on antidiabetic medications. Thus, the situation is still somewhat muddled, but the cinnamon statistics—four out of six studies showing positive results—are clearly favorable.
Plasma and Serum—What’s the Difference?
In the cinnamon study described in the accompanying article, the authors used samples of the subjects’ blood plasma and blood serum for purposes of measuring the levels of numerous chemical compounds. Their reasons for stipulating both plasma and serum are not important from our point of view, but let’s just ask a question: Do you know what the difference is between those two?
You probably know that when a blood sample is placed in a centrifuge to separate out the solid matter (red blood cells, white blood cells, and platelets), what remains above the solids in the centrifuge tube is a clear yellowish liquid called plasma.
Blood plasma is an aqueous (water) solution of hundreds of dissolved chemical compounds, both organic and inorganic. Among these are: nutrients, such as glucose, amino acids, and fatty acids; vitamins and minerals; hormones, such as insulin, corticosteroids, and catecholamines; innumerable proteins, carbohydrates, and lipids (including cholesterol); and metabolic waste products, such as carbon dioxide, urea, and lactic acid.
Now pay attention: plasma contains a number of soluble proteins that are involved in the process of coagulation, or clot formation—and that is what distinguishes plasma from serum. If coagulation occurs, the resulting clots precipitate out of the plasma, leaving . . . serum.
Thus, serum is the simplest form of the blood fluid (note the s’s, to help you remember which is which). If to serum you add the proteins involved in coagulation, you have plasma (note the p’s). And if to plasma you add the blood solids, you have whole blood. In your arteries and veins, of course, there’s just whole blood, so there the distinction between plasma and serum is moot; it becomes significant, however, in the laboratory.
When scientists refer to the concentration of a dissolved substance in your blood, they generally eschew the term “blood level” in favor of “plasma level” or “serum level,” both of which reflect the fact that the substance in question is dissolved in the liquid part of your blood, not in the solid part (red and white blood cells and platelets). Since there’s no meaningful difference between plasma and serum inside your circulatory system, the terms plasma level and serum level are essentially synonymous in that context.
Did you notice, by the way, that both the terms liquid and fluid were used above? Is there a difference between those two? Not in medicine, where they’re used interchangeably. In the physical sciences, however, there is a difference: all liquids are fluids, but not all fluids are liquids, because gases are also fluids (substances that flow). In medical parlance, the term fluid virtually always means liquid, and gases are called gases.
- Ziegenfuss TN, Hofheins JE, Mendel RW, Landis J, Anderson RA.
Effects of a water-soluble cinnamon extract on body composition and features of the metabolic syndrome in pre-diabetic men and women. J Int Soc Sports Nutr 2006;3(2):45-53.
Could Your Body Composition Stand Any Improvement?
An additional, unique feature of the American study with prediabetic adults was measurement of body composition (muscle vs. fat), as mentioned above. Here the results with cinnamon showed a small but statistically significant increase, by 1.1%, in lean mass compared with the control group, and a decrease in fat mass by 0.7%. That may not be enough to make members of the opposite sex gasp in admiration, but every little bit helps when it comes to improving our bodies.
The authors stated,
Based on the results of this study, [the cinnamon extract] may play a beneficial role in ameliorating the effects of several chronic diseases of modernization. Although speculative, because subjects in this study were not required to follow any specific diet or exercise program, it is possible that combining [the cinnamon extract] with a nutrient-dense diet and/or a regular exercise program may lead to even greater health benefits.
Mulberry Leaf Works in Asia . . .
As readers of this magazine surely know, cinnamon is not the only natural substance that is beneficial against insulin resistance and diabetes. There are a number of herbal products and chemical compounds that are helpful. Here we will mention some new evidence in support of one of them: mulberry leaf (Morus alba), which is probably best known for being the favorite food of silkworms. As mentioned in a previous article (“Mulberry Helps Control Blood Sugar, and More,” November 2004), some researchers use leaves of the closely related species Morus indica; both are considered to be beneficial.
A recent paper by scientists in Minnesota begins with the forthright statement, “In Asia, type 2 diabetes is treated with mulberry leaf.” It’s reasonable to assume that this is done because the treatment works. Naturally one wants to know how and why it works, or at least to verify via controlled clinical trials that it does indeed work. So the Minnesota researchers designed a study (presented in very sketchy form in their paper) to augment those that had gone before.
The idea here was to test the effects of mulberry on blood glucose levels in diabetic patients and healthy controls who were given a 75-g dose of sucrose (table sugar). Sucrose consists of one molecule each of the simple sugars glucose and fructose joined by a chemical bond. In the intestines, that bond is broken by the enzyme sucrose α-D-glucosidase, yielding the individual glucose and fructose molecules, which traverse the intestinal wall and enter the general circulation.
The researchers recruited 10 diabetic patients (who were taking antidiabetic medications) and 10 healthy controls. For the test, the fasting subjects were given the 75 g of sucrose (dissolved in hot water) and 1 g of mulberry leaf extract (oddly, the species was not identified) or placebo.
. . . And Here Too
Gratifyingly, the results showed that mulberry significantly reduced the increase in blood glucose levels typically seen in this kind of test. It also increased the levels of hydrogen gas in the patients’ breath, a telltale sign that it had inhibited the action of sucrose α-D-glucosidase, thereby causing sucrose malabsorption. That this was the likely mechanism of mulberry’s action was suggested by another recent study, by Japanese scientists, using samples of intestinal tissue taken from both humans and rats. The mulberry they used was Morus alba.
Yet another study, this one by scientists in India, indicated that mulberry (Morus indica in this case) has beneficial effects in rats, both on blood glucose levels and on the levels and activities of certain liver enzymes that play important roles in gluconeogenesis, the synthesis of glucose from noncarbohydrate sources, such as proteins and fats. The rats used in this study had diabetes that was induced by a drug called streptozotocin, and the beneficial effects of mulberry exceeded those of an antidiabetic drug called glibenclamide.
How Lucky Do You Feel?
As Dirty Harry, Clint Eastwood memorably asked a hapless punk, “Do you feel lucky?” It’s probably hard to ignore a question asked of you when you’re staring down the barrel of a really big gun. What you, dear reader, are staring at, just by virtue of being an American (or a citizen of another industrialized country), is an increased risk for the metabolic syndrome, or worse. Lucky for you, however, you have the freedom to make wise lifestyle—and nutritional supplement—choices that can nearly eliminate that risk. Choose well.
- Ziegenfuss TN, Hofheins JE, Mendel RW, Landis J, Anderson RA. Effects of a water-soluble cinnamon extract on body composition and features of the metabolic syndrome in pre-diabetic men and women. J Int Soc Sports Nutr 2006;3(2):45-53.
- Blevins SM, Leyva MJ, Brown J, Wright J, Scofield RH, Aston CE. Effect of cinnamon on glucose and lipid levels in non-insulin-dependent type 2 diabetes. Diabetes Care 2007;30:2236-7.
- Mudra M, Ercan-Fang N, Zhong L, Furne J, Levitt M. Influence of mulberry leaf extract on the blood glucose and breath hydrogen response to ingestion of 75 g sucrose by type 2 diabetic and control subjects. Diabetes Care 2007;30(5):1272-4.
- Oku T, Yamada M, Nakamura M, Sadamori N, Nakamura S. Inhibitory
effects of extractives from leaves of Morus alba on human and rat small
intestinal disaccharidase activity. Br J Nutr 2006;95:933-8.
- Andallu B, Varadacharyulu NC. Gluconeogenic substrates and hepatic gluconeogenic enzymes in streptozotocin-diabetic rats: effect of mulberry (Morus indica L.) leaves. J Medicinal Food 2007;10(1):41-8.
Will Block is the publisher and editorial director of Life Enhancement magazine.