How Cinnamon Controls Blood Sugar
We're not talking about sticky, sugar-laden, insulin-inducing cinnamon rolls here. This much-loved spice has actually shown evidence of lowering blood sugar.
While long used as a flavoring, current research is beginning to confirm health benefits of cinnamon, whose traditional therapeutic use included treatment of chronic bronchitis.1
Cinnamon Controlls Diabetes
In a trial of type 2 diabetics reported in 2006, an extract of cinnamon that provided the equivalent of 3 grams powdered cinnamon consumed daily for four months resulted in a 10.3% reduction in fasting plasma glucose from levels measured at the beginning of the study, compared with a 3.4% reduction in the placebo group.2 Participants with higher fasting plasma glucose levels at the beginning of the study derived the greatest benefit.
Cinnamon has also been shown to lower hemoglobin A1c, a marker of long-term glucose control. A randomized trial of 109 type 2 diabetics with elevated hemoglobin A1c levels who received usual care in addition to 1 gram cinnamon daily for 90 days resulted in greater reduction in hemoglobin A1c in comparison with usual care alone.3
Additionally, a trial of 58 poorly controlled type 2 diabetic men and women found reductions in hemoglobin A1c as well as mean systolic and diastolic blood pressures after 12 weeks of cinnamon supplementation compared with a placebo group.4
In Chinese type 2 diabetics, 120 or 360 milligram per day doses of cinnamon extract in addition to gliclazide therapy for three months resulted in a reduction in hemoglobin A1c and fasting blood glucose levels while these levels remained unchanged in the placebo group.5
In a trial that included overweight or obese subjects with impaired fasting blood glucose, cinnamon given twice daily for 12 weeks was associated with an increase in plasma antioxidant status and a decrease in malondialdehyde, a marker of oxidative stress.6
"This study supports the hypothesis that the inclusion of water soluble cinnamon compounds in the diet could reduce risk factors associated with diabetes and cardiovascular disease," authors A. M. Roussel and colleagues conclude.
Cinnamon Helps Maintain Optimal Blood Sugar Control
A trial of healthy subjects conducted by Swedish researchers found a decrease in blood glucose after eating and a delay in gastric emptying among those who received 6 grams cinnamon compared to those who did not receive it.7
A subsequent study conducted by the Swedish team that evaluated the effects of 1 and 3 grams cinnamon revealed a reduction in serum insulin and an increase in glucagon-like peptide 1 (a hormone that helps prevent high blood glucose levels) in those who received the 3 gram dose.8
Another study involving healthy participants found reductions in total plasma glucose responses to orally administered glucose and improved insulin sensitivity when 5 grams cinnamon was consumed immediately or 12 hours before oral glucose tolerance testing.9
A subsequent study conducted by the researchers in which healthy men were supplemented with 3 grams cinnamon or a placebo for 14 days resulted in reductions in glucose and insulin responses to oral glucose tolerance testing at the end of the treatment period, however, these benefits were rapidly lost once cinnamon was discontinued.10
In nonalcoholic fatty liver disease patients, daily supplementation with 1,500 mg cinnamon for 12 weeks was associated with decreases in fasting blood glucose, insulin resistance, total cholesterol, triglycerides, liver enzymes and high-sensitivity C-reactive protein, a marker of inflammation.11
Polycystic ovary syndrome (PCOS) is a condition not necessarily characterized by cystic ovaries (as its name implies) but by insulin resistance. In a pilot study involving 15 women with PCOS, cinnamon consumed daily for eight weeks resulted in significant improvement in insulin resistance compared to a placebo as indicated by fasting and two hour oral glucose tolerance test results.12
Interestingly, a recent article appearing in Food and Chemical Toxicology suggests that cinnamon inhibits the misfolding of human islet amyloid polypeptide that is regarded as a causative factor in type 2 diabetes mellitus.13 The authors of the study identified proanthocyanidins as the main anti-amyloidogenic compounds occurring in cinnamon water extract and discovered that these compounds also decreased human islet amyloid polypeptide aggregation's damaging and toxic effects.
A review published in 2007 concluded that cinnamon was well tolerated and has a "possible modest effect in lowering plasma glucose levels in subjects with poorly controlled type 2 diabetes”, and adds the usual disclaimer that diabetics should not use cinnamon in place of the proven standard of care.14
A meta-analysis of eight randomized placebo-controlled trials involving participants with diabetes and/or prediabetes published in 2011 concluded that "Cinnamon intake, either as whole cinnamon or as cinnamon extract, results in a statistically significant lowering in fasting blood glucose."15
Subsequent meta-analyses of six and ten clinical trials involving diabetics came to similar conclusions.16,17
Cinnamon has shown its value among populations who are looking to optimize their glycemic control. There appears to be a variety of valuable, recent human studies on this beloved ancient spice.
We conclude this review with a study of hyperglycemic subjects who were given a 250 mg dried water-extract cinnamon capsule twice per day or a placebo. Participants in this 2010 study showed a reduction in fasting glucose after two months.18 One should take immediate action at the first signs of hyperglycemia to lessen the chances that diabetes will develop.