Many of you have probably heard of the research that suggests taking cinnamon can lower your blood sugar. It could even be a helpful supplement for people with type 2 diabetes and pre-diabetic states such as metabolic syndrome, but there is still quite a degree of controversy. Not all clinical trials have been positive and some reviewers are either negative about its value,1 or unconvinced.2 Of particular relevance was the 2008 meta-analysis (this is where the data from several clinical trials are pooled and re-analysed) by Baker and team that found (using results from four clinical trials) cinnamon did not improve blood sugar control in patients with type 2 diabetes (T2D).1
As a result, I was neutral in my view of the value of cinnamon, awaiting more evidence. That evidence has now arrived!
Getting the right form of cinnamon is the key
The first thing we should do is clarify which cinnamon we are talking about. The cinnamon typically used as a spice in cooking is Ceylon or sweet cinnamon (Cinnamomum zeylanicum). It can be quite expensive, and a better quality product comes as rolled up pieces of bark known as quills. Studies on this form of cinnamon in terms of controlling blood sugar levels are few and have largely been negative.3,4 The most studied form of cinnamon in T2D, and the one that has generated the positive data, is the cassia or Chinese cinnamon (Cinnamomum cassia, also known as C. aromaticum). This traditional Chinese herb is not as commonly used as a spice, although it can appear as a cheap (sometimes undeclared) substitute for Ceylon cinnamon. In any case, it is readily available as a dietary supplement.
Looking now at the recent clinical trials, a 2011 meta-analysis by US scientists found a positive effect for cassia cinnamon.5 The meta-analysis included eight studies: four were in T2D patients, three in patients with pre-diabetes and one in healthy controls. Results confirmed that the herb significantly lowered fasting blood glucose (FBG). Some trials used cassia cinnamon bark extract and others the powdered bark, with the effective dose of herb appearing to be around 3g of herb per day. Of note, the percentage decline in FBG was similar to the amount achieved by the drug metformin (at around 6%).
Analysis reveals that cinnamon helps with blood-sugar control
This was followed up by a 2012 systematic review and meta-analysis that included the six best clinical trials to date (in the opinion of the authors).6 All of these trials were of cassia cinnamon and dated from 2003 to 2010. The total number of patients was 435 and the trials lasted 40 days to four months using doses ranging from 1g to 6g/day. The meta-analysis found significant decreases in FBG and HbA1c (glycosylated haemoglobin, a longer-term measure of blood sugar control).
Here are some of the features of the more recent trials that were included in this meta-analysis. A 2009 US study tested 1.8g/day of cassia cinnamon over 90 days in 109 patients with T2D (randomised, controlled trial, no placebo).7 Cinnamon reduced mean HbA1c from 8.5% to 7.6% (p < 0.01). A 2010 UK study used 2g/day in 58 patients with T2D over 12 weeks (randomised, placebo-controlled, double blind trial).8 Not only did cinnamon significantly reduce mean HbA1c (from 8.22% to 7.86%, p < 0.005), there was a small but significant (p < 0.001) reduction (about 4mm Hg) in both systolic and diastolic blood pressures.
Lowered fasting blood sugar by 11 per cent!
Finally, a 2012 three-month Chinese study examined the impact of either 120mg/day of cassia extract (from 2.4g of bark) or 360mg/day in 66 patients with T2D (randomised, double blind, placebo-controlled trial).9 This trial has not yet been plugged into any meta-analyses because it is too recent. While both doses were found to be effective, there appeared to be no advantage from using the higher dose. The 120mg/ day extract significantly lowered FBG by 11% (versus a decrease of 2% in the placebo group) and triglycerides by 27% (against a small rise in placebo). HbA1c values were also significantly lowered by this dose of cassia cinnamon extract: from 8.90 to 8.23%, versus no change in the control group.
This is all rather convincing evidence of the value of cassia cinnamon in helping to regulate blood sugar. I suggest a dose of about 1g (as the powdered herb, or the equivalent amount in extract form) before each meal. A word of caution though in the case of T2D: cassia is just one of the supplements to take. It should not be relied upon on its own unless the T2D is very mild and it won’t be a substitute for modern drugs: it should be viewed more as an add-on treatment. Be sure to talk to a doctor skilled in natural medicine before adding it to your routine.
And it could be an add-on treatment with additional value. A German group investigated the impact of a combination of cassia (4g as a single dose) and acetic acid (the main component of vinegar) on a single meal (milk rice sweetened with glucose) in 27 healthy people. The combination significantly improved blood glucose and satiety (feeling of fullness) immediately after the meal. Another recent clinical study found that cassia cinnamon for 12 weeks exerted a clinically relevant and significant antioxidant effect on 22 people with pre-diabetes.To your better health,
Nutrition & Healing
Volume 7, Issue 3 – March 2013
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