The use of cinnamon goes back thousands of years. This culinary spice has a sweet, pungent flavour that makes it a long-standing favourite among cooks, but there is also an ongoing interest in its possible health benefits.
What is cinnamon?
The bark of several species of South-east Asian plants that all belong to the genus Cinnamomum is used as the spice commonly known as cinnamon or cassia. Only one of these species, C. zeylanicum (or C. verum), sometimes called Ceylon cinnamon, is technically the 'true' cinnamon. Cassia refers to one of the related species, with C. aromaticum (or C. cassia) being the one most commonly sold, often as cassia cinnamon or Chinese cinnamon.
Cinnamon is a popular sweet, pungent spice used to add flavour in baking and cooking, but it has also been used in traditional Chinese medicine and other traditional medicines, for centuries. Cinnamon bark is made into powders, teas, liquid extracts and capsules. The spice sold as cinnamon in most supermarkets is usually a combination of both cinnamon and cassia.
Are there benefits linked to cinnamon or cassia cinnamon?
There is some laboratory evidence suggesting that cinnamon might have anti-inflammatory, antioxidant and antibacterial properties, but research is limited.
There is also inconclusive evidence that cassia cinnamon, or C. aromaticum, may help improve blood glucose and cholesterol levels in people with type 2 diabetes. Studies of cinnamon on animals indicate anti- diabetic activity in both 'true' cinnamon and cassia cinnamon. However, further research is needed in human studies before recommendations can be made.
Are there any risks associated with cinnamon?
When used as a spice in part of a normal diet, it is unlikely that cinnamon will have any adverse reactions.
Cinnamon as a spice within a normal diet normally has no side effects. However heavy consumption may cause irritation of the mouth and lips, leading to sores. Some people have experienced allergic reactions to cinnamon when applied to the skin.
Cinnamon contains coumarin, a compound in warfarin, which is a medicine taken to prevent blood clotting, so seek medical advice about cinnamon supplements if you are already prescribed blood thinners.
Cassia cinnamon has more coumarin than 'true' cinnamon, which has led the German Federal Institute for Risk Assessment in 2006 to warn against consuming large amounts of cassia cinnamon.
Coumarin might worsen or cause liver disease, so people with liver disorders should avoid taking cassia cinnamon and cinnamon supplements. Patients with cancer affected by hormone levels, such as breast cancer, should use caution in taking cinnamon as it has shown oestrogenic and anti-oestrogenic effects in some studies.
Because chemicals in cinnamon can interact with other medications, if you take any regular medication, talk to your GP before taking cinnamon supplements. Supplements could interact with antibiotics, blood thinners and heart medicines, and diabetes medication, along with other medication.
If you are taking cassia cinnamon and will be scheduled for surgery, stop taking it at least two weeks before the operation because it may interfere with blood sugar control.
Never use cinnamon as a replacement for conventional medicine, especially in cases of diabetes.
Dietitian reviewed by Catherine Collins RD.