I've been thinking about cutting back on coffee. Two questions I have are:
- Is there a mechanism through which coffee could interfere with insulin levels? I always thought that because black coffee is non-caloric, it doesn't spike glucose or contribute to insulin resistance. But a quick Google search seems to show that the waters are murky.
- Is coffee a bad idea for people with low COMT activity?
In a cross-over study, coffee drinking raised basal insulin levels
van Dam, R., Pasman, W., & Verhoef, P. (2004). Effects of Coffee Consumption on Fasting Blood Glucose and Insulin Concentrations: Randomized controlled trials in healthy volunteers. Diabetes Care, 27(12), 2990-2992. doi:10.2337/diacare.27.12.2990
I think the problem w/ large amounts of caffeine is the effect it has on catecholamines and the 'chemical stimulation' of fight/flight response. It's ultimately inflammatory and there was a recent headline/paper that said ~5 cups of coffee a day worsened Alzheimer's symptoms.https://www.medicalnewstoday.com/articles/321406.php
I've not read that paper.
My guess is there probably is some kind of U-shaped response where 1-2 cups is probably fine, depending on whether or not you have the gene for fast/slow metabolizer of coffee. If you are a fast metabolizer, then more is probably OK.
I think green tea is preferred over coffee.