A few years ago I wrote about coumarin content in cinnamon, which has proven to be a very popular blog post. Noting that I didn’t really talk about “what cinnamon is good for”, I thought I’d write a companion piece to describe why you should use cinnamon liberally in your life (besides the fact that it just tastes great!)
Medicinally, cinnamon boasts a long list of health benefits, from anti-microbial (cinnamon is sometimes used in breads as a preservative), a digestive stimulant, and even some early evidence of inhibiting melanoma (cancer) cells in animal trials (Braun and Cohen, 2015). What I want to focus on in this article is the growing evidence of using cinnamon for healthy blood sugar.
Clinical Trials on Cinnamon
With the prevalence of Type 2, or insulin-resistant, diabetes in the United States today (37.3 million, or 11.3% of the US population per the Diabetes Research Institute Foundation, 2022), there is quite the interest in studying cinnamon’s traditional use to lower blood sugar. Allen, et al (2013) completed a meta-analysis of 10 randomized controlled trials (RCTs) with a total of 543 adults with Type 2 diabetes. They concluded that taking cinnamon (Cinnamomum cassia) at doses ranging from 120 milligrams up to 6 grams daily for 4-18 weeks reduced fasting blood glucose by an average of 25 mg/dL. As a bonus, improvements in cholesterol, triglycerides, and LDL (“bad”) cholesterol levels were also reported. What’s not to love?
Unfortunately, the review further concluded that cinnamon did NOT have a significant impact on HbA1c – the blood marker that characterizes the long term (3-4 month) picture of glucose present in the blood. Allen, et al (2013) suggest that this may be because many of the trials included lasted less than 12 weeks, which may not have been enough time to influence the A1c.
The above study was 12 years old, so I went looking for something more recent. I found another meta-analysis from 2019 (Deyno, et al) that reviewed cinnamon for healthy blood sugar. Guess what? This paper concluded that cinnamon significantly reduced fasting blood glucose as well as something called “HOMA-IR”, which stands for Homeostatic Model Assessment for Insulin Resistance. HOMA-IR is a mathematical model that approximates insulin resistance.
Like the Allen, et al (2013) study, Deyno, et al (2019) also concluded that cinnamon did not significantly reduce HbA1c. Doses used in the 2019 meta-analysis ranged from 1 gram up to 14.4 grams/day (averaging about 3.3).
Herbalist’s Aside
It is important to note a distinct difference between how RCTs are necessarily conducted and how herbs are used clinically.
One of the foundations of a RCT is to “control the variables”. This means that typically a single substance (drug, herb, etc) is tested against a control group that gets a placebo (an inert substance). Participants are unaware whether they are receiving the test substance or the placebo, and scientists measure results. By limiting the variables and comparing to a “non-treatment”, it is thus easier to pinpoint the cause of any benefit (or harm) of the substance.
Herbal medicine, in practice, rarely uses an herb in isolation. We herbalists are trained to combine herbs to produce a synergistic effect. Simply put, an increased response can be obtained by combining herbs for a therapeutic purpose. The concept of “synergy” even goes so far as to say that the effect of a combination of herbs is greater than the sum of the effect of using the herbs individually. Isn’t that neat?
All that to say is that, even though RCTs may show only a modest improvement with the use of cinnamon alone, effects are often magnified when using in conjunction with other herbs (or drugs). Unfortunately, conducting a clinical trial on multiple substances at once adds complications, which is why it is not often done.
(Slight) Caution about Cinnamon
Cinnamon is so tasty, though, so what do you have to lose by shaking some on your oatmeal in the morning? Both meta-analyses reported that cinnamon was well-tolerated in most of the studies included.
Please do prepare your cinnamon shaker, but continue reading for some additional clarifications and caveats.
Both meta-analyses tended to use a particular species of cinnamon – Cinnamomum cassia, also known as cassia cinnamon. Cassia cinnamon is readily available on the market, but it does come with a slight warning that it contains a small amount of coumarin – a natural blood thinner – that, in high doses, can cause liver damage. This was the subject of my aforementioned cinnamon/coumarin post.
C. verum, also known as true cinnamon or Ceylon cinnamon, contains only negligible amounts of coumarin. However, in terms of blood sugar regulation, the evidence is not as strong for Ceylon cinnamon as it is for cassia cinnamon. Natural Medicines (2020), a subscription-based database of “just about any medicinal herb you can think of” summarizes that the clinical research currently does not support efficacy of Ceylon cinnamon to significantly lower blood glucose. Still, Natural Medicines reports fewer studies using Ceylon cinnamon as compared to cassia cinnamon, so this may just be a case of lack of evidence.
Use Cinnamon!
Nevertheless, warming cinnamon is a safe herb for culinary use. For general health I recommend adding it liberally to flavor foods from baked goods to your breakfast cereal to vegetables (it’s particularly good sprinkled on winter squash or carrots before roasting).
If you are looking to use cinnamon for healthy blood sugar (or some other, specific medicinal purpose), it is also generally safe to use at appropriate therapeutic doses. Please consult with your local herbalist if you have any concerns or questions about how much to take (and what kind) for your particular situation and need.
Allen, R., Schwartzman, E., Baker, W., Coleman, C., & Phung, O. (2013). Cinnamon Use in Type 2 Diabetes: An Updated Systematic Review and Meta-Analysis. The Annals of Family Medicine. 11(5) 452-459. DOI: https://doi.org/10.1370/afm.1517
Braun, L. & Cohen, M. (2015). Herbs and Natural Supplements: An Evidence-Based Guide. 4th Ed. Elsevier.
Deyno, S., Eneyew, K., Seyfe, S., Tuyiringire, N., Peter, E., Muluye, R., Tolo, C., Ogwang, P. (2019). Efficacy and safety of cinnamon in type 2 diabetes mellitus and pre-diabetes patients: A meta-analysis and meta-regression. Diabetes Research and Clinical Practice. 156(2019). 107815-107828. DOI: https://doi.org/10.1016/j.diabres.2019.107815
Diabetes Research Institute Foundation (2022). Diabetes Statistics.
Natural Medicines (2020). Cassia cinnamon monograph. Retrieved from: https://naturalmedicines.therapeuticresearch.com/
Natural Medicines (2020). Ceylon cinnamon monograph. Retrieved from: https://naturalmedicines.therapeuticresearch.com/