Short answers, pulled from the story.
Ceylon cinnamon comes from Cinnamomum verum and uses only the thin inner bark, giving it a lighter color, finer texture, and more delicate flavor that fades during cooking. Cassia cinnamon, which includes Chinese, Indonesian, and Vietnamese varieties, uses all bark layers, producing a harder, thicker, more pungent product. Most cinnamon sold internationally is cassia, not Ceylon cinnamon.
According to Pliny the Elder, a Roman pound (327 grams) of cinnamon cost up to 1,500 denarii, the equivalent of fifty months of labor. The price was driven by a deliberate trade secret: merchants in the Mediterranean world concealed the spice's true origin for centuries to protect their monopoly as suppliers.
In 2023, world cinnamon production totaled 238,403 tonnes, with China, Vietnam, Indonesia, and Sri Lanka together accounting for 98% of the total. China alone produced 39% of the world's supply.
Cassia cinnamon typically contains well over 1 mg of coumarin per gram, sometimes up to 12 times that amount. The European Food Safety Authority set a maximum tolerable daily intake of 0.1 mg of coumarin per kilogram of body weight in 2008, because coumarin causes liver and kidney damage at high concentrations. Ceylon cinnamon (C. verum) contains only trace amounts of coumarin.
In March 2024, the US Food and Drug Administration recommended a voluntary recall on six brands of cinnamon apple sauce after 500 reports of child lead poisoning across the United States. The FDA determined that cinnamon in pouches manufactured by AUSTROFOOD S.A.S., using cinnamon from Negasmart, both of Ecuador, had been adulterated with lead chromate. Both suppliers were placed on a Red List.
A 2023 meta-analysis of six prior meta-analyses found modest but significant decreases in fasting plasma glucose and haemoglobin A1C from cinnamon supplementation. However, the 2012 Cochrane review concluded there is insufficient evidence to support using cinnamon for type 1 or type 2 diabetes, and the U.S. National Center for Complementary and Integrative Health stated in 2017 that studies in people do not support using cinnamon for any health condition.