Apparently so, in a small but very good randomized controlled trial. 40 days of cinnamon (Cinnamomum cassia) in 1, 3 and 6 gram doses–that’s 1/5 teaspoon, 2/3 teaspoon, and 1.2 teaspoons respectively–was taken as medicine, in capsules.
Cholesterol and triglycerides dropped significantly in all three groups at day 40 (23 to 30%; p < 0.05). Cinnamon now joins other foods that lower cholesterol, as reported in, remarkably, The Wall Street Journal. It's clear that certain herbs and spices are anti-inflammatory, and have high levels of antioxidants, and can be part of an anti-inflammatory diet. And that certain diets influence the immune system and response either positively or negatively.
Diabetes may actually be predicted by antioxidants in the diet. Other supplements–specifically psyllium, fenugreek, and glucomannan–are promising for type 2 diabetes as well. Search for recipes for diabetes here.